Highly Allochthonous Archive

My blog lives up to its name

2007-03-01T18:18:00.001Z

Further update: Highly Allochthonous is now found at:

http://all-geo.org/highlyallochthonous.

I am beginning to theorise that this is a cast iron example of nominative determinism.

When I started blogging, I had no real idea where it would lead. I didn’t know whether I would, or could, produce regular content; or whether anyone else would read it if I did. After a sluggish start, I found that the answer to the first question was yes. As for the second, the number of visitors to this site has been slowly but surely increasing, especially over the last few months; I could hardly claim to be setting the blogosphere alight, but I was reasonably content with progress.

But then, in a rather bewildering fortnight at the end of January, not only do I get the Naturejobs gig, but an e-mail arrives out of the blue from Scienceblogs, inviting me to the top table. And, as such, Highly Allochthonous is on the move; please click through to its shiny new home at http://scienceblogs.com/highlyallochthonous/.

To be honest, I’m still not sure whether I’ll be able to hack it with the big boys (I certainly won’t be able to match the prodigious output that some of them achieve), but it’s an exciting opportunity to get a wider audience. Of course, I’m hoping everyone who has already discovered me will drop in every so often, if only to brag that you read me “in the glory days, man, before he decided to play it safe and post nothing but pretty pictures!”

The bureaucratic run-around

2007-02-27T14:53:00.000Z

This morning, armed with my contract and my passport, I set out to register at my new academic home. I was told that I needed to go the International Office, which proved to be the starting point of a rather long and convoluted morning of being shunted around campus:

The staff at the International Office tell me I need a student number from Biographics department.

I head downstairs to the Biographics department, who tell me that before they can give me a student number I need to go to the Science Faculty Office to get the relevant form.

Across campus at the Science Faculty Office, after some confusion I get given a form, which seems more like a student degree application form than anything else, and get told that at some point I will need to pay a fee to ‘unblock’ my registration.

Back at the Geology department, after checking that I’m not literally on a wild goose-chase, I fill in the sections of the form which actually seem relevant.

Back to Biographics, who tell me that the form needs to be stamped by the International Office.

Upstairs at the International Office, they stamp my form, but tell me that my account must be unblocked my paying the fee at the Finance Office.

I venture the other way across campus to the Finance Office, where I queue for 20 minutes or so to pay the fee.

Back in once more to Biographics and finally get my student number.

Return in triumph to the International Office – they give me yet another form to take back to Finance (I’m starting to think that my first visit – and payment – was unnecessary, but no-one seems sure).

After shuttling between a couple of people in the Finance Office, they tell me I am now ok to register at the Science Faculty Office.

I return to the Science Faculty Office, where they discover my account is still blocked. After 10 minutes of phoning around (what a novel concept!) I finally get registered.

I was an undergraduate at a University that has had eight centuries to perfect its administrative opacity, but I have to admit, I’m thoroughly impressed. At least I can say that I got some exercise this morning, and got a lot of practice in finding my way around the campus.

If at first you don't get published in Nature, cheat

2007-02-26T09:00:00.000Z

Just a quick plug whilst I settle in down here in Jo'burg...

Actually, I've never even tried to get properly published in Nature - I've yet to stray into fields of study that are 'sexy' enough. Nonetheless, thanks to the mysteriously vanished Postblogger's heads-up, I'm getting the chance to sneak a few words of wisdom into print, as one of this years' four Postdoc Journal keepers. 200-250 words a month might not seem like very much wisdom, but I know some very long words...

My first entry was published the Thursday before last. Quite why I was deemed worthy is uncertain - I suspect that my exotic post-doc destination probably helped matters, but I suspect that all the writing practice I've had on these pages in recent months probably helped too.

In transit

2007-02-22T19:33:00.000Z

The last week or so has been... intense. The speed at which moving to another country went from a theoretical possibility to imminent reality caught me completely unawares, and I suddenly had a million things to do and too little time to do them in. Somehow I got most things organised, I suspect more due to luck than judgement, and now - with a few hitches - I'm on my way.

What's weird is that not only do I not know what to expect when I arrive in Johannesburg, but I've been so focussed on the departure date that I haven't even thought about it until now. A 12-hour flight lies between me and finding out.

Valentine’s Day Massacre

2007-02-15T23:24:00.000Z

Other people may have received cards telling them how wonderful they were yesterday – but not me. Instead, I got a nice long e-mail from JGR regarding two papers I submitted way back in June (which I have alluded to previously) which was about as far from ‘roses are red…’ territory as you could get.

I haven’t really talked about the research behind these papers on this blog (I guess I didn’t want to pre-empt publication, somewhat ironically), but they were basically presenting the major conclusions of my PhD project – a study of the tectonic evolution of New Zealand in the last 20 million years, using paleomagnetic measurements to look at crustal rotations. My first paper presented my dataset, which took a lot of work to amass, and the second was my attempt to construct a model of deformation to explain these data.

I’m still chewing over the reviews (they’ve hardly arrived at a convenient time!), but the basic gist seems to be that they don’t like my data - although they couldn’t really find much wrong with it – and they really don’t like my model. They were very keen to point out to me that accommodating the large and fast crustal rotations my data seem to indicate (much larger and faster than has previously been suggested) is not easy, and my suggestions for how it has happened are a little bit at odds with the well-established picture. Never… anyway, there’s a lot to filter and think about, which obviously I don’t have time to do at the moment, so for now I’m just going to have to go:

AAAAARRRRRRRRRRGGGGGGGGGGGHHHHHHHHHHHH!!!!!!

instead.

How to waste even more time with Google Earth

2007-02-13T18:05:00.000Z

I dare you to visit this rather funky map quiz and not get addicted.

My only complaint is that the pictures containing nothing but ocean floor are a little bit too difficult...

(thanks to Ron).

Wasting your life, creationist style

2007-02-12T23:32:00.000Z

I suppose as a geologist I should feel angry and aggrieved about this newly minted PhD student:

…Dr. Ross is hardly a conventional paleontologist. He is a “young earth creationist” — he believes that the Bible is a literally true account of the creation of the universe, and that the earth is at most 10,000 years old.

For him, Dr. Ross said, the methods and theories of paleontology are one “paradigm” for studying the past, and Scripture is another. In the paleontological paradigm, he said, the dates in his dissertation are entirely appropriate. The fact that as a young earth creationist he has a different view just means, he said, “that I am separating the different paradigms.”

Later in the article is becomes fairly clear that his motivation for getting his doctorate is to use “the fact that he has a Ph.D. from a legitimate science department as a springboard [for pushing a literalist viewpoint].”

I can’t bring myself to be angry about this, though (even though I can understand why others might). Instead, I find it sad; a waste of half a decade or more of someone’s life. Getting through a PhD is no picnic at the best of times; in my experience it’s only your fundamental enthusiasm and interest in your subject that gets you through. Forcing yourself through the whole traumatic process when you believe, deep down, that every word you write, every measurement you make, and every conclusion you draw is fundamentally mistaken – well, let’s just say that I can’t see it doing wonders for your mental well-being.

Over at PZ’s (where this story came to my attention - see also Chad's take), a large proportion of the comments are debating whether the University of Rhode Island would be justified in withdrawing his doctorate - or even, given that they knew about his young-earth beliefs before he applied, whether he should have been admitted to the PhD programme in the first place. I’d have to unequivocally answer no, and yes, respectively. In the context of a PhD you can only be judged on what you have submitted, and his supervisor tells us all we need to know:

His subject was the abundance and spread of mosasaurs, marine reptiles that, as he wrote, vanished at the end of the Cretaceous era about 65 million years ago. The work is “impeccable,” said David E. Fastovsky, a paleontologist and professor of geosciences at the university who was Dr. Ross’s dissertation adviser. “He was working within a strictly scientific framework, a conventional scientific framework.”
…
“We are not here to certify his religious beliefs,” he said. “All I can tell you is he came here and did science that was completely defensible.”

Presuming that this is an accurate representation of his dissertation, it’s a no-brainer: he came, he followed the rules, and he advanced his field: so he earned his doctorate, however galling it may be that he has proceeded to use his qualification in the manner that he has – to add a veneer of scientific authority to flawed creationist arguments.

Besides, there’s something else interesting about this story: the fact that when push came to shove, to get his qualification he had to follow the ground rules of science. And when he did that, what happened to all those big, obvious, gaping holes in the scientific picture of an old earth and common descent that we hear so much about? Did he try, even slightly, to cast some light on those holes with his research? It doesn’t look like it to me. Rather than a bold assault on the evil Darwinian empire, we get some meandering about “working within a particular paradigm of earth history”. Likewise, despite his self-declared mission to destroy Darwinism, it seems that Johnathan Wells kept his powder dry during his time at Berkeley. In both cases, the choice to use the PhD qualification as a rhetorical weapon, rather than the PhD research, pretty much tells you all you need to know.

Contestants, raise your hammers...

2007-02-10T17:42:00.000Z

From the Berkeley Geological Association blog (with some snipping):

Geolympics is the ultimate in field geologist competition. This yearly event should put to the test all the field practices geologist's are trained to perform with accuracy and time contraints as parameters of success.

1) The Brunton: Imagine 5 or so rocks with varying strikes, dips, slickenlines, etc. that need measuring whilst being timed.

2) Rock Demolition: Imagine a line of geologists armed with a basketball size chunk of granite and their favorite rock hammer. They are timed to see who can smash their rocks into chunks no bigger than a baseball.

3) Twisted Map Folding: Imagine a new crisp map completly unfolded and a geologist blind folded who must then, by feel alone, fold the map into its original orientation while being timed.

4) Gear Up Gear Down: Imagine a geologist pulling up his/her truck when the clock starts and they must exit the vehicle and gear up with boots, hand lens, brunton, hammer with loop, acid bottle, map, rain gear, the works then when complete screaming ROCK IT! and then undressing again into street clothes, packing away the gear and firing up the truck again.

A few more potential events occur to me:

Contact free running: A test of mapping skill and athleticism. Contestants have to precisely follow a contact between two formations, across hill, dale, ravine, cliff face, river, bracken, and bog. Points for speed, accuracy and style.
Drilling time trial: One for the paleomagicians amongst us. Contestants are given an hour to drill, orient and extract as many core samples as they can. Scoring is based on the length of the cores as well as the number (i.e. an 8cm core which yields 3 standard paleomagnetic samples scores the same as three cores which yield only one each). Solo and pair events.
Geo-orienteering: Like orienteering, except you have a geological map and specified rock samples must be gathered from each control point.

I'm sure you guys can come up with some more events...

Reality intrudes on blogging

2007-02-09T16:26:00.000Z

You might have noticed that things fell silent here only two days into my promised seven-day epic. As it has turned out, the reasons I prevaricated about signing up to the Just Science challenge in the first place have defeated me: exam marking to get through, a couple of presentations to give, and, due to the fact that next week is my last week here in Southampton, lots of departmental loose ends to tie up. As if that weren’t enough, just when I’d figured that the South African Consulate were going to tell me to get lost, on Wednesday my passport came back with a nice visa stuck in it. It’s really happening – in two weeks, I shall be arriving in South Africa to start my new job. Which means that I have quite a lot to get done between now and then...

Anyway, although I had a number of half-completed posts lying around, and I believed that I would have enough time to polish and post one up every day, I have ended up being too busy, or too tired, to really give them they attention they deserve. And, if I’m honest, my motivation was also sapped by the realisation that for some reason, my posts were appearing in the Just Science aggregator dated as 1969 or something, and were not appearing in the RSS feed either.

However, whilst I have failed miserably, at least one geoblogger is making a good fist of it: Brian is going from strength to strength with a great series of posts on sedimentary geology. I particularly liked Wednesday’s post about the modelling of depositional systems in big tanks.

Stalagmite records individual storms and intensities

2007-02-06T22:28:00.000Z

In last months’ post about climate records from stalagmites and other speleothems, I concentrated on their potential for giving us detailed regional climate information over long time periods: 10s, and even 100s, of thousands of years. However, this article at Mongabay.com highlights some research concerned with records preserving climatic variations over much shorter timescales, and one of the more contentious issues in modern climate research: how the frequency and intensity of hurricanes is affected by our warming climate.

It seems that the towering storm clouds and humid atmosphere associated with hurricanes and other tropical cyclones produce rainwater which is extremely light isotopically (it has &delta¹⁸O 6 per mil more negative than normal precipitation), and a lot of it falls in a short time when a storm hits land. Amy Frappier and her colleagues decided to test if this pulse of storm water could affect the &delta¹⁸O of the groundwater enough to leave a signal in speleothems growing in underlying caves.

We used a computer-controlled dental drill to carefully mill off layers of powder from a fast-growing stalagmite [from Actun Tunichil Muknal caves, Belize], where each sample reflects cave drip water over periods of a week to a month. Analyzing these rock powders using standard techniques, we were able to detect brief spikes from recent hurricanes and tropical storms that produced rain over the cave - even when those storms struck only weeks apart!"

The effect is clearly illustrated by this figure from a paper Frappier et al. have just published in Geology [1]. Tropical cyclones which have hit Belize in the last 30 years (A) correlate well with short negative excursions in &delta¹⁸O (B). These excursions are superimposed on a longer-term pattern related to the El Nino Southern Oscillation (the 15 month offset with the El Nino record in C represents the time it takes rainwater to percolate from the surface to the cave). The accompanying carbon isotope record also shows the El Nino variation, probably due to changes in soil respiration rates, but not the storm events, showing that they are due to a separate forcing (heavy storm precipation).

The final subfigure D is interesting, as it indicates that stronger storms (plotted in A) seem to produce larger excursions. Going back to the Mongabay piece:

"We also found that the relative size of spikes that we measured was related to the intensity of the storm, which is encouraging for the prospect of reconstructing the intensities of pre-historic landfalling storms.."

There’s currently a lot of debate over possible changes in storm numbers and/or intensity as a result of anthropogenic climate change (RealClimate has a good summary of the science) – some people claim there is already a clear signal, but others say that the historical data just isn’t good enough. Speleothem records can’t help resolve one of the major issues, the detection of non-landfalling storms, but it seems that they can potentially give us a much longer term record of trends in tropical cyclone intensity than is currently available; and a better idea of how much natural variability there was in the past can only help.

[1] Geology 35, p111-114 (doi).

This post was published on Day 2 of the Just Science challenge – a full week of science and only science. You can subscribe to the RSS feed at http://www.justscience.net/?feed=rss2.
All my posts for this week

Spot the planetary difference

2007-02-05T18:18:00.000Z

There are many differences between Titan’s atmosphere and Earth’s, in terms of temperature (a couple of hundred degrees lower) and composition (no oxygen, more methane), but the cloud formation recently snapped above Titan’s north pole by Cassini, shown in the top image above, doesn’t look too dissimilar from storms snapped from our own planet’s orbit, as the lower image (source) illustrates. At 2400 km in diameter, it is quite a whopper - it would fill most of the North Atlantic.

It’s not that clouds haven’t been imaged on Titan before; we managed that even before Cassini arrived in Saturnian orbit, and Cassini itself has imaged some before now as well. But those previously observed cloud systems were mainly located around the south pole of Titan; what’s interesting about this one is that it is in the opposite hemisphere, directly above the lakes which have caused so much excitement. This makes it extremely tempting to link the two phenomena. The northern hemisphere of Titan is now entering its spring after a seven-year winter, so evaporation from these lakes in the rising temperatures could easily have contributed to the formation of clouds.

The key question, though, is what happens then: do significant amounts of hydrocarbons rain back out of the atmosphere to complete the “methanological cycle”? Is this precipitation intense enough be actively eroding out the landscapes imaged by the Huygens lander on its descent, and produce standing bodies of hydrocarbons in depressed topography? Or, rather than being refilled from above, are lakes on the surface more to do with hydrocarbon release from either subsurface “methanifers”, or cryovolcanic venting?

Some of these questions are still open. During Huygen’s descent, it measured variations in atmospheric methane concentration and temperature which, when examined in detail, indicated the presence of thin methane clouds capable of generating a persistent light drizzle [1]. Such weather makes the surface of Titan the natural location for any British extraterrestrial colony, but it is not really energetic enough to carve new drainage channels or any other new topography. And although attempts to model Titan’s atmosphere do suggest that strong storms can occur [2], how common or important they are in reality is unclear. Effectively, what we need is more observation time. Just like continuous observations of Mars over several years have revealed changing features which might indicate actively flowing water, if Cassini is able to observe Titan for long enough, we might not only see a few storms but also be able to assess their effect on the landscape.

[1] Tokano et al., 2006. Nature, 442, 432-435, [doi].

[2] Hueso and Sánchez-Lavega, 2006. Nature, 442, 428-431, [doi].

This post was published on Day 1 of the Just Science challenge – a full week of science and only science. You can subscribe to the RSS feed at http://www.justscience.net/?feed=rss2.
All my posts for this week

Prepare for 7 days of pure science

2007-02-04T22:39:00.000Z

After a lot of dithering, I've signed myself up for the Just Science Challenge:

we would like to propose a Week of Science, to begin on Monday, February 5, and end on Sunday, February 11. During that time each blogger should post about science only, with at least one post per day. Furthermore, issues which are favored by anti-scientific groups (creationism, global warming, etc.) should be either avoided, or discussed without reference to anti-scientific positions.

I like to think I am fairly science-focused anyway, or at least that my digressions into other realms do not overwhelm the geology. But I like the idea of having a week where we don't let creationists, denialists and the other forces of antiscience dictate any of our output. Besides, it's always nice to stretch myself, and a post a day is enough of an increase in my average output to be a nice challenge, even if I've cheated a little by putting in a fair amount of preliminary groundwork.

A day in the life

2007-02-02T17:54:00.000Z

Lab Lemming wants to know what I do in a typical day. I’m not sure I have a “typical day”, but today is as good as any other I suppose.

Job title: Paleomagnetism technician (bear this in mind for what follows)
Insitution: School of Ocean and Earth Sciences, National Oceanography Centre, Southampton.
Date: Friday 2nd February, 2007

Prevailing conditions:

The deadline for handing in the third year mapping projects is Monday
Semester 1 exams have just finished
Our cryogenic magnetometer is not being used this week because we need a helium refill (which was going to be done this morning but has been put back to Monday).

8:30-8:45: Walk into work
8:50: Switch on my computer and open exam paper to mark.
8:55: Computer beeps – student has e-mailed wanting me to check their map before they print it
8:55-9:15: In computer room consulting with stressed and sleep-deprived student.
9:20: Get back to my office to find another pile of exam scripts on my chair. This lot really liked my question, it seems.
9:20-10:00: Marking
10:00-10:15: Another student wanting help with his cross-sections
10:30-10:45: Yet another student; this one wants his report abstract checked, and reassurance regarding the word limit.
11:00-11:20: In lab to show a fourth year undergraduate how to do susceptibility measurements (for their dissertation project).
11:30-11:45: Get fed up with constant interruptions and go and have coffee.
11:50-12:00: Dragged back to the lab by panicky student who thinks she’s broken the computer. She hasn’t, it’s just so old (DOS, no less) that she doesn’t really get how it works.
12:00-12:45: Marking.
(12:25: Course co-ordinator pops in to check that I have got the latest batch of exam scripts. He’d like them back early next week (!) )
12:45-12:50: Some more students, this time people doing 4th year dissertation who want to book some lab time.
12:50-1:30 pm: Lunch.
1:30-2:45: Finally get a moment of quiet to get through some marking. Promisingly, most appear to be written in a language resembling English.
2:45-3:00: Start sending out e-mails about laboratory schedule for the coming weeks (given that it’s going to be chaos when I leave, I want to make sure everyone has some machine time).
3:00-3:30: Reinvaded by stressed students.
3:30-3:45: A bit more marking.
3:45-4:30: More mapping consulation down in the computer room with even more stressed and sleep-deprived students.
4:30-4:45: Need caffeine.
4:45-5:00: Work on lab schedule for those who have bothered to respond to my e-mails.
5:00-5:30: Finalise marks on first exam question. Two more to go!
5:30-5:45: Tidy stuff up before heading to the pub for a well-earned pint or three.

It’s not like this every day – Thursday was spent mainly trying to sort out someone’s misorientated sample data, Monday will mainly be spent sorting out the helium refill. The common theme, perhaps, is that of me doing a lot running about on other peoples’ behalf.

I’m passing this on to Transient Reporter (assuming that he’s not snowed under changing nappies, I don’t really want to hear about that) and Thermochronic, but everyone should pile in. Now, where's that pint...

Linking up

2007-02-02T10:28:00.000Z

Philosophia Naturalis #6 is up at Science and Reason. Lots of physical science goodness, but scandalously no geology - which is at least partly my fault for not getting around to submitting any suggestions. Perhaps our growing band of geobloggers should fortify ourselves with gin and tonic and gatecrash next months edition at Geek Counterpoint.

On that subject, you may or may not have noticed the new occupant of my sidebar - an amalgamated feed of recent posts from all the geobloggers I'm aware of, created using Google Reader's nifty 'share' function. I thought it was a convenient way of making all (any) of my readers aware of what everyone else in the geoblogosphere is up to. At the rate it's been ticking over in the last week, quite a lot.

Anyone is welcome to hijack the feed (if you can't find the relevant script in my source page, let me know and I'll send it to you) - the more cross-linking the better for all of us, I reckon. And if you write (or know of) a geoblog I've yet to include, drop me an e-mail.

Lusi – the man-made mud volcano

2007-02-01T13:49:00.003Z

The latest from Lusi

In May 2006, an exploratory gas well being drilled in eastern Java hit a limestone aquifer. Because the lower part of the well had not yet been ‘cased’ - sealed off from the surrounding rock - a surge of overpressured water was released into the mudstones higher in the borehole, fracturing them and mixing them into a hot mud which eventually made its way to the surface near the drilling rig.

Since then, since then, 7,000-150,000 cubic metres of mud* a day has been disgorged from a vent dubbed ‘Lusi’, burying surrounding villages. I found this video on You Tube showing the encroachment of the mud – a rising tide which shows no sign of stopping.

From a more elevated perspective, here’s a satellite image. I think those huts on the bottom left of the second panel are the ones you see at the end of the video

This is from a recent GSA Today paper by Davies et al.[doi], which confirmed that the drilling into the aquifer was probably responsible for the eruption; the company operating the well (understandably) tried to implicate an earthquake which occurred two days beforehand, but any seismogenic effects should have been immediate (and detectable as a pressure change in the borehole), and ‘liquefaction’ tends to affect less cohesive sands more than mud.

You can read more on this at PhysOrg. Then read how they’re planning to put a stop to it:

Indonesian geophysicists hope to stem the flow of a destructive mud volcano on East Java by dropping chains of concrete balls into its mouth…

… Last week, the government team tackling the disaster approved a plan that will use 1,000 steel chains to try to slow the flow of mud. Each chain is 1.5 metres long and links together four concrete balls — two that are 40 centimetres across and two that are 20 centimetres across. Each ball and chain set will weigh about 300 kilograms. The balls themselves will be modified to maximize their friction with the mud.

Apparently, they think this will restrict the flow without just causing it to divert somewhere else. I suppose it depends on how fractured the rock is, but I’d say it’s a long shot at best.

Update:And, a month later, this rather bizarre plan swings into action. On Saturday, they only managed to drop one chain because a steel cable on the hoisting mechanism broke. They managed sixteen more on Monday, but then they hit another potential snag when they looked at the telemetry from sensors attached to the chains, as another site has reported under the arresting title ‘Volcano consumes concrete balls’:

The balls slid one kilometre into the crater, roughly twice the depth anticipated, so many more than planned may be required to staunch the mudflow, said the operation's spokesperson Rudi Novrianto.

"Based on our monitoring of Monday's operations, we may later decide to add to the number of ball chains, but the decision will only be made once the initial target of 374 chains have been dropped into the mud hole," he said…

…Basuki Hadimuljono, the head of the team trying to plug the steaming crater, was quoted by the Koran Tempo newspaper as saying that the number of chains required may rise to 1 000 from the initial estimate of 374.

I remain unconvinced that this is going to work, but you can’t fault their perseverance.

(Thanks to Geology News for the heads-up which led to the update).

*In media units, that’s up to 40 olympic swimming pools.

Fiddling while my blog burns

2007-01-31T08:37:00.000Z

I've been putting off the switch to the new blogger template system because, like Propter Doc, I've been having trouble getting the expandable post summaries to work properly. Rewriting the javascript which did the trick on my old template to use the new metadata labels, and get past a seemingly much fussier XML parser, proved to be a long exercise in fiddling, but I've finally managed it. For those who are interested, this is the code I used. You have to be in the HTML view with the widgets expanded to insert it:

<script type='text/javascript'>
var memory = 0;
var number = 0;
</script>

Then scroll way down the page until you find the div for the post-body and insert the stuff in bold:

<div class='post-body'>
<b:if cond='data:blog.pageType == "item"'>
<style>span.fullpost{display:inline;}</style>
<p><data:post.body/></p>
<b:else/>
<style>span.fullpost{display:none;}</style>
<p><data:post.body/></p>
<script type='text/javascript'>
var permlink='<data:post.url/>';
var title='<data:post.title/>';

var spans = document.getElementsByTagName('span');
var number = 0;
for(i=0; i <spans.length; i++){
var c = " " + spans[i].className + " ";
if (c.indexOf("fullpost") != -1) {
number++;
}
}

if(number != memory){document.write('<p><a href=' + permlink + '>"'+ title + '" continues...</a></p>') }
memory = number;
</script>

</b:if>

<div style='clear: both;'/>

The bit in brackets in the document.write statement can be changed if you want it to say something different. Now, when you're writing a post, you just stick the bit you don't want to appear on your front page between <span class="fullpost"> and </span>, and off you go!

Note that I didn't write the original code - I've just (I think) bodged it to work in the new system. Here's another way to do it, from someone who looks like he might know what he's talking about, although for some reason I couldn't get that to work either.

I'll be fiddling with other bits of the template in the next few days, so apologies in advance for when I break the HTML (Update: ~~which I see is already the case for IE users. Bloody Microsoft!~~ OK, have fixed it (sort of) although all the posts vanish to the bottom of the page if you shrink the window too much. Seriously, people, get a better browser.

New data on the revision habits of the modern student

2007-01-29T23:49:00.000Z

In one of the courses I taught last semester, the exam has asked pretty much the same questions every year for the last five years. This doesn’t exactly reflect well upon those doing the teaching, and this year (my second of covering these lectures) I made a deliberate decision to do something a bit different with the questions from my part of the course. The exam is divided into two sections: a ‘numerical’ part focussed on data manipulation and calculating things, and an ‘essay’ part. For the former, instead of asking the usual question about triple junction stability and migration, I gave them a question where they had to assess the quality of some paleomagnetic data and use them to calculate when a terrane (a highly allochthonous one, no less) collided with a larger continent.

I realised at the time that this alteration could potentially act as a useful survey of the study practices of our undergraduates. The question I set was actually pretty easy – if you’d bothered to revise the part of the course about paleomagnetic field tests and calculation of paleolatitudes (I’d even, after some debate, given them the relevant equation, and therefore wondered if it wasn’t a little too easy). However, students in thrall to the art of ‘question spotting’, who only revised the small bit of the course about triple junctions, might be in a little bit of trouble.

Today I received the scripts from the exam; no-one had answered my numerical question. Not one student.

Although that means I have less marking to do, part of me can’t help but find that a little bit depressing. The weird thing is, plenty of people answered one or both of the essay questions I set – both of which asked about parts of the course which previous years' questions hadn't, and at least one of which requires some knowledge of paleomagnetic techniques to answer properly. Maybe then, this just indicates a degree of mental inflexibility (‘It’s not a triple junction question! Panic!’) rather than damagingly limited revision practices. I suppose I’ll find out when I read the essays…

Update: OK, after a bit of investigation, it seems there are a number of factors at play here:

Of the other two questions in the relevant section, one, on seismic moment and earthquake hazards, has been mixing and matching the same three subsections for at least the last four or five years; the other, on elastic bending of a plate in response to seamount loading, must have been seriously highlighted by the lecturer because I was asked to help with exactly the same question a week before the exams.
I have some testimony to the effect that the students pretty much assumed that ‘my’ question would be of the same type as it had been in previous years (despite the fact that someone else had taught the course for most of those years), and revised (rather selectively) with that assumption in mind.
If I’m scrupulously honest with myself, the way the question was worded might have made it seem that it was a lot more work than it actually was: not every step was explicitly spelt out, and the style (“This is the scenario. This is your data. Calculate stuff” style, rather than “Calculate x. Calculate y. Calcuate z.”) was perhaps a little intimidating. I’m open to the possibility I was also asking to much for a 45 minute question, but sadly I have no data to test that.

So, faced with two other questions they had prepared for, and one which they hadn’t and might have looked like a lot of work, the students opted to shun me. I’m not sure anyone comes out of this particularly well, to be honest. In my own defence, I have a fair number of essay questions to mark, so obviously I wasn’t being a fully bastard examiner from hell.

Milankovitch goes solar?

2007-01-25T23:06:00.000Z

From New Scientist:

Robert Ehrlich of George Mason University in Fairfax, Virginia, modelled the effect of temperature fluctuations in the sun's interior. According to the standard view, the temperature of the sun's core is held constant by the opposing pressures of gravity and nuclear fusion. However, Ehrlich believed that slight variations should be possible [due to instabilities caused by interactions with the Sun’s magnetic field]…

…Ehrlich's model shows that whilst most of these oscillations cancel each other out, some reinforce one another and become long-lived temperature variations. The favoured frequencies allow the sun's core temperature to oscillate around its average temperature of 13.6 million kelvin in cycles lasting either 100,000 or 41,000 years. Ehrlich says that random interactions within the sun's magnetic field could flip the fluctuations from one cycle length to the other.

These two timescales are instantly recognisable to anyone familiar with Earth's ice ages: for the past million years, ice ages have occurred roughly every 100,000 years. Before that, they occurred roughly every 41,000 years.

The paper is up on arXiv, and his model also has an oscillation in the 22,000 year range as well. This strikes me as a mighty big coincidence; it’s not like we’ve pulled the frequencies of variations in the Earth’s orbit - the Milankovitch cycles generally held to control long-term climate fluctuations - out of thin air. One thing I’d really like to know how sensitive the periods of these solar oscillations, if they exist, are to changes in the temperature structure of the sun, which I suspect we haven’t constrained with absolute precision. That said, a solar oscillation in the 100,000 year range might solve the problem of why it’s such a dominant signal in the climate record.

Anyone care to guess how long it will take for someone to claim this somehow has a bearing on the reality of anthropogenic climate change?

Update: Those of you who don't see the disconnect should head over to Open Mind for a clear explanation of why we think that the current short-term warning we're all worried about cannot be attributed to solar variability)

The writing in the cave walls

2007-01-23T23:00:00.000Z

There’s a really nice post up on RealClimate about extracting climate records from stalagmites. Stalagmites and other speleothems form when water, percolating down from the surface and picking up dissolved carbon dioxide and other minerals on the way, penetrates into a cave system. When it reaches the cool, dry air of a cave, the carbon dioxide can escape from solution and carbonate minerals precipitate out. Take a steady drip of water, leave for a few thousand years, and voila:

The exciting part comes when we look at a cross-section through a stalagmite: just like tree rings, chemical changes in the different carbonate layers - particularly changes in the oxygen isotope values – reflect changes in the water falling on the land above the caves when that layer was deposited, and hence potentially give us high-resolution information about climatic variations over tens of thousands of years. Even better, you can determine the age of deposition using uranium-thorium dating; so what we potentially have is a source of climate records comparable to those we can get from ice cores (allowing us to independently check their chronologies), but globally distributed; you get caves on every continent, not just Antarctica and Greenland.

One thing this lets us look at is the variations in the strength of the monsoon through the last few glacial cycles. In the northern hemisphere summer, air rising above the warming land draws in moist air from the oceans to the south. The resulting rain is isotopically light (it has a negative &delta¹⁸O) because it has become fractionated by more evaporation and transport. A longer, wetter, stronger summer monsoon should therefore lead to lighter groundwater &delta¹⁸O than a shorter, drier, weaker, one; and that is exactly what we see in stalactites in the relevant regions. Here’s a record for most of the Holocene from Oman [1], showing both long term (over thousands of years) and short-term (over decadal and centennial timescales) variations in monsoon strength:

And here’s a longer term record, going back through a number of 21,000 year precessionary cycles, compiled from three overlapping stalagmite records from the Hulu Caves in China [2]. This second figure also plots the average summer insolation (black curve), and the Greenland ice core &delta¹⁸O (which tracks temperature – blue curve). The correlation is very good (especially if you look at a better version of the figure) – suggesting that the monsoon is stronger when it is warmer in Greenland. Centennial scale variations in Greenland have been linked to changes in the themohaline circulation, so these data give us some indication of the global effects such changes can have.

The variations in the monsoon being studied in these papers is a very strong climate signal, but as measurement and analytical methods get more sensitive and sophisticated (for example, the Hulu record has recently been extended back to 180,000 years ago [3]), tracking smaller regional variations in climate will become much easier. These results clearly show how, as this recent Science editorial [4] argues, “the age of the speleothem” could be upon us.

[1] Fleitmann et al., Science 300, 1737-1739 (2003)
[2] Wang et al/, Science 294, 2345-2348
[3] Hai Cheng et al., Geology 34, 217–220, 2006
[4] Henderson, Science 313, 620-622, 2006

The vacuous quantify the nebulous (again)

2007-01-22T23:11:00.000Z

The news on the radio this morning informed me that today is apparently most depressing day of the year.

Being contrary, I was actually feeling pretty good today. A proper weekend off, visiting some friends in Salisbury and visiting the Avebury stone circle, meant I actually had a fairly productive Monday. So, other than the continuing lack of news on the South African visitor permit front, the only depressing thing about today was the media's insistence on not only running with a supremely silly 'yes kids, in science there really is an equation for everything' story, but also recycling it from previous years.

If taking a few values we can quantify (debt and income levels, time elapsed since Christmas), at least as many which you most certainly can't ('general motivational levels'? 'the need to take action'? Please.) and randomly planting them in a forest of brackets wasn't vacuous enough, both the culprit (a serial offender it seems) and the media seem to have missed the fact that this magic formula was quite comprehensively falsified last year...

Did you know your irony meter could go 'whee'?

2007-01-15T23:46:00.000Z

It seems that the MP-nagging activities of your friendly neighbourhood science bloggers has caught the attention of Truth In Science, although I was a little puzzled that they directed their readers to this post rather than the one with the letter from my MP. The one that quite clearly states that the Truth In Science packs are “not a suitable resource for the science curriculum”.

Ah. That’s because they’re trying to spin the Department of Education’s response. A pinch of selective quoting (‘not an appropriate resource to support the science curriculum.’ becomes ‘not “appropriate…to support the science curriculum.”’), and off we go!

The national curriculum is a minimum standard. It exists to guarantee that every young person receives a basic education. Teachers are free to go teach more than the minimum requirements of the national curriculum. Even if intelligent design is “not included in the science curriculum,” this simply means that it is not compulsory in all schools. It does not constitute a ban.

So a statement that a certain teaching pack can’t be used as part of the science curriculum really means that it’s ok to use it - you just don’t have to. How kind.

But, thanks to this sterling bit of reasoning, today I learnt that my irony meter can go ‘whee’. It’s a whole new setting that I wasn’t even aware of.

Updating the geoblogosphere

2007-01-15T18:28:00.000Z

Those coping with the sad loss of Down to Earth, rejoice - a couple of other new(ish) earth science oriented blogs have been brought to my attention:

Apparent Dip (thanks to Lab Lemming).
...Or Something, which is especially notable for several cool geological photos.
Olelog. Lots of general geological goodness.

Meanwhile, Kevin Vranes is jumping the Scienceblog ship, but thankfully he'll still be treating us to his climate change/policy musings at Prometheus, and going all wildernessy on us at NoSeNada.org.

Finally, if RealClimate doesn't slake your climate blogging thirst, try Open Mind (via Tim Lambert) or Head In a Cloud.

Precambrian black smokers

2007-01-14T18:20:00.001Z

These are pretty cool – some excellently preserved black smoker chimneys from a 1.43 billion year-old massive sulphide body in northern China:

Hydrothermal vents occur at mid-ocean ridges or volcanic hotspots: seawater, permeating down through cracks in the crust, comes into contact with hot rocks above the magma chamber, and reacts with them as they are heated to a couple of hundred degrees C - leaching out metals such as lead, copper, zinc and iron. These hot, buoyant fluids then return to the surface at vent sites, mix with sulphate-rich seawater and rapidly cool, leading to the precipitation of iron sulphides in chimney-like structures. Here’s a more typical view:

Individual vents are generally short-lived, and when the upwelling hot fluids inevitably migrate somewhere else, the fragile spires tend to collapse under their own weight. Massive sulphide bodies – valuable sources of metal ore - are built from the debris of many generations of collapsed smokers in a long-lived vent field. So it’s quite rare to see such well-preserved fragments. I just wish the authors had included some pictures of the things in situ.

Under the microscope, you can even see evidence of fossilised microbes: on the outside of the chimneys are stromatolite-like ‘microbialites’ – layered deposits of sulphides and organic carbon, sometimes containing mineralised filaments similar in morphology to bacteria found in and around modern vents.

Hydrothermal systems - where interesting chemistry is driven by geothermal energy – is considered to be one place on the early Earth where life could have perhaps arisen; those favouring such a scenario (which includes those hoping for extraterrestrial life in places like Europa) will be happy to see evidence of a flourishing ecology in such environments so long ago.

Source: Li and Kusky (2007), Gondwana Research, in press [doi]

Too windy for wind turbines?

2007-01-11T12:17:00.000Z

Certain witty and erudite public figures here in the UK have an annoying habit of making somewhat ignorant pronouncements on anthropogenic climate change, preferring to deny that it's happening at all rather than talk about the more complicated (and valid) issues of how badly it might affect us (or not), or what mixture of adaptation and mitigation would best serve us. Jeremy Clarkson is one such person. The Radio 2 DJ Terry Wogan is another. Despite his form, I was intrigued by one item of discussion (or, more accurately, lengthy mockery) on his breakfast show this morning, namely that in the stormy weather that we're currently enjoying, 'it's too windy for the wind turbines!' Ha ha ha.

It turns out that wind turbines are shut down at wind speeds above about 65 mph, because the faster rotation of the blades at high wind speeds can either overheat the generator, or cause 'overspeed' problems whereby the blade rotation becomes impossible to control or stop (see p20 of this pdf). This is a simple consequence of optimising the turbines to the usual (slower) wind conditions, but it does raise an important issue. Other forms of renewable energy such as wave and solar are also compromised by stormy weather, meaning that during a serious storm, even without damage to the distribution system a renewables-heavy generation mix could well leave a lot of us without power.

To avoid such problems, you either need enough non-renewable (nuclear, gas, coal) capacity to act as a backup, which places fundamental (low) limits on renewable generation, or you need to somehow store the energy produced by the renewables in better weather. The latter is currently impractical at a large scale, which is one argument in favour of distributed generation (where batteries and heat sinks can be used). However, it seems that people are experimenting with using wind generators to produce hydrogen fuel. Using renewable power to produce energy-rich chemicals would be an interesting way of getting round the problem; in pure speculation mode, I wonder if you could use wind turbines to turn atmospheric CO2 back into hydrocarbons?

Feel free to say hola

2007-01-11T11:51:00.000Z

Higher powers inform me that this week has been declared as Delurking Week. An invitation to any normally mute, semi-regular browsers to say hello, say them; a cunning use of emotional blackmail to garner praise and validation, say I.

Still, self-assessment is a difficult thing, so in addition to random hellos, I would be interested to hear any comments, impressions, or suggestions on possible topics you might have.

Westminster: bastion of scientific illiteracy

2007-01-10T19:15:00.000Z

Miss Prism’s MP favours ”a balanced approach to the various theories of origin." in secondary school science classes. Odd, I thought we were talking about evolution, not the origin of life.

So far, 2 out of the 7 MPs that are known to have been contacted about the Truth in Science packs appear to be comfortable with mixing up empirical science and religious faith. This is admittedly a small sample size, but taken with the fact that more MPs felt moved last November to rejoice about 100 years of Rugby League than register their support for the Early Day Motion about Truth In Science, it doesn’t exactly instil great confidence in our elected representatives. At least the Department of Education were prompted to action, making a strong statement which my MP gave me a preview of (update: and people coming here via the Truth In Science should definitely read). And heartening scepticism of the commentators on this short article by Truth In Science member Richard Buggs is a nice contrast to the norm, too.

Best endorsement ever?

2007-01-08T10:49:00.000Z

Apparently Highly Allochthonous is 'harder to pronounce than "Pharyngula" '. It's almost tempting to change my tagline...

Titanian shores

2007-01-06T14:30:00.000Z

Details of the proposed polar lakes on Titan first announced in July, have been published in Nature by Stofan et al. (see also the accompanying News and Views article). The “lakes” are found in topographic depressions, and are thought to be filled with liquid based on their very low radar backscatter, which means whatever is in them is very smooth and reflective. This might seem counter-intuitive until you realise the radar beam is being sent towards to surface at an angle, rather than just straight down. A smooth surface therefore acts as a tilted mirror, reflecting energy away at the incident angle rather than back towards Cassini; a rough surface will contain parts with the correct orientation to return radar energy.

These features are by far the smoothest and most reflective found on Titan, and the contrast with the surrounding regions is quite sharp, as the figure below shows: the top row are false colour radar data with and without noise correction, and the bottom row are horizontal and vertical profiles of the normalised radar cross section (NCRS – a measure of the returned radar energy) along the white lines shown in b. -25 dB is about the level of instrument noise.

What’s also clear in the radar images is a very lake-like morphology, with irregular edges and what look like channels draining into the main body. The similarity is really brought home by this lovely image from the JPL press release:

It’s important to note that radar can’t tell us for sure that what we are seeing here are liquid hydrocarbons, although it does indicate a material with a low dielectric constant (i.e. it’s not a polar liquid, like water), as you’d expect. The authors also note:

Our inference that the northern-hemisphere lakes discovered by Cassini radar are at least partly liquid methane is consistent with various other considerations. If such lakes cover at least 0.2–4% of Titan's surface … they will buffer the atmospheric methane's relative humidity at its observed value, removing the requirement for a putative steady drizzle at the equator. If the abundance of lakes seen in [these] data are typical of their coverage poleward of about 70° in both hemispheres, then the fraction of Titan's surface covered by lakes is within this range. More recent polar radar data from Cassini support this assertion.

It is also unclear how these lakes are filled: is it by methane rain, or do the depressions cut into a subsurface methane aquifer? If the former, you would expect seasonal variations in how large and full the lakes are. Hopefully Cassini will keep collecting data long enough for us to observe, or rule out, such variations.

Philosophia Naturalis #5: Some sciblogging New Year’s Resolutions

2007-01-04T10:30:00.000Z

The New Year may merely represent an arbitrary point in the Earth’s orbit with no intrinsic significance, but the flipping over of the digits on the calendar seems to have a real psychological effect, compelling us to dream up grandiose promises to improve ourselves and our lives. Of course, we then spectacularly fail to keep most of them, but this month’s edition of Philosophia Naturalis attempts to mirror this spirit of self-improvement by asking: what makes science blogging good science blogging? A trawl through the past month’s activity in the science and technology blogosphere suggests that, at their best, scibloggers perform a number of vital functions, which we can all try to emulate:

To augment the media coverage of science

It’s an unfortunate fact that you don’t have to know anything about science to be a science correspondent for a major newspaper or news channel – if anything, having a science degree probably counts against you. The very best people overcome this, of course, but a lot of mainstream science reporting seems to consist of slightly rewritten departmental press releases (which may also have been ‘rewritten for clarity’ by non-scientists). If you want nuance and context, science bloggers are on hand to pick up those vaguely explained findings in the mainstream media – be it reports of running water on Mars, the latest results from the Stardust probe, the origin of weird gamma ray bursts, the topology of the Universe, or the year’s top 5 nanotechnology breakthroughs - and run with them.

To talk about the ‘unsexy’ science the media does not reach

Reports of cutting-edge breakthroughs are all very well, but to really understand what those breakthroughs mean you need to know the basic science as well. Blogging gives us scientists the opportunity to talk about the nuts and bolts of their disciplines, such as how particles detectors work (in the run up to the LHC being switched on next year), or how stars manufacture the elements that form us all. We can also rectify the puzzling lack of media interest in our particular (and, obviously, intensely interesting) subfield by waffling to our heart’s content about strange correlations between the structure of the Cosmic Microwave Background and the orientation of our solar system, or the ‘interpretation question’ in quantum mechanics.

We can also compensate for the media’s notoriously short attention span; the results being breathlessly publicised are only a snapshot of research programmes which can play out over decades, as various hypotheses are proposed, tested, then discarded or modified. For example, there was a lot of excitement a few months back about possible liquid water on Enceladus, but it is interested bloggers who now tell us that this is not the only possible explanation for those geyser-like plumes.

To show that scientists are people too

It’s a sad fact that the common caricatures of scientists – as soulless reductionists with no empathy, social skills, or ethical qualms (with a nice sideline in big frickin’ lasers and maniacal laughter) are not often recognised as exaggerations. Blogging gives scientists a chance to express their real voices and personalities, and show that our lives are in fact, fairly normal: OK, we may talk about methods of solving Rubik’s cubes as well as soap operas, and we may have appalling taste in T-shirts, but our jobs have both good days and bad days. And worse days. And days when our experiments produce stupid results. We make mistakes. And, of course, we have arguments. Big arguments. Over things like whether string theory is the best thing since sliced bread or a half baked blind alley, or whether the entire universe can usefully be described as a computer, or if worries that climate change science is being stretched too far to gain political traction are justified. We find the idea that we're all engaged in a battle to suppress The Truth about global warming, or evolution, or the age of the Earth, rather hilarious - any 'orthodox conspiracy' of more than two scientists would undergo a schism faster than you could say, 'splitters!'

To fight the forces of ignorance and antiscience

There is a lot of silly science out there. The media sometimes shoots itself in the foot by giving silly answers to nonsensical questions, or giving free publicity to pointless mathematical concepts (though we can also be slightly more generous).

But darker forces, which don’t just mindlessly mangle science but actively slander it, are also at work. Defending against these attacks might be like playing whack-a-mole, but it must be done: and it’s nice to see that even if the US National Park Service’s are somewhat coy over the age and geological history of the Grand Canyon, there are science bloggers willing to step into the breach.

To provide the wow factor

Who better than scientists to inspire people with their tales of just how cool the Universe is? Not enough of us take the time, which is why we still miss Carl Sagan ten years after his passing. However, if a picture speaks a thousand words, then Phil has amassed ten thousand spectacular words over at Bad Astronomy (plus a few more of his own), and the HiRise team also do their bit with more stunning images from the Mars Reconnaissance Orbiter. Us geologists produce some very cool pictures too, so maybe I should take this one particularly to heart in the coming year.

Thus concludes this month’s edition of Philosphia Naturalis - may science blogging continue to flourish in 2007. Thanks to you all for reading, and to the contributers (willing and unwilling) for writing. PN #6 will be hosted by Charles Daney at Science and Reason on Thursday, February 1. Send your nominations and suggestions to carnival@scienceandreason.net, as explained here. We’re also looking for bloggers with a physical sciences/technology focus for hosting future editions; more information, and links to past editions, can be found at the Philosophia Naturalis site.

A geo-historical revolution

2007-01-02T16:31:00.000Z

I’m actually in work today, despite the building being Officially Closed: you can still come in, but there’s no heating or canteen staff to provide coffee. However, an opportunity to engage in some warming ROFL’ing is provided by Adamant (via Pharyngula): a merging of the sequence of events in the geological record, scaled according to the biblically-based timescale of Archbishop Ussher, and human history. Here are some highlights which appeal to the paleogeographic nerd in me:

1384 B.C.: Shang Empire scraps compass research when China drifts over south magnetic pole.
1314 B.C.: On his way home from Troy ,Odysseus makes wrong turn into Tethys Ocean ;Homer writes it up.
A.D. 1492: Panama's rise from sea thwarts Columbus's discovery of Japan.
A.D. 1522: Sneak asteroid attack by Hernan Cortez smashes Aztec Empire
A.D. 1588: Spanish Armada frustrated by continuing absence of English Channel.

Of course, the Young Earth Creationists think that most geology was confined to the year of Noah’s Flood, so this parody suffers from being rather less ridiculous than the ideas it is parodying.

Why 2007 might be better than 2006

2007-01-02T15:14:00.000Z

If I was asked to sum up my life last year, the phrase ‘treading water’ would seem appropriate. Although I passed my PhD and had two papers published at the beginning of the year, the work that went into them was mostly done in 2005. Since then, my research output has stalled a little, other than a couple of co-author credits. This hasn’t been helped by two first-authored papers submitted in June being consigned to review purgatory, but the depressing reality was that my position was not designed to help me build my own scientific career, rather to support others’ (my boss, other members of the group). This was far more depressing, and irksome, than the strange disconnect between my position (and salary) and my teaching responsibilities. Worse, my attempts to find a new job (both academic and non) had all fallen flat, so much so that offers from someone I know in the exploration industry to join the Dark Side were starting to seem tempting – a sure sign of dissatisfaction. Some have it much worse than me, of course, but I was starting to feel trapped and seriously demotivated.

Suddenly, though, a change is in the air, with an almost-to-good-to-be-true job offer from a research group in South Africa. They need a postdoctoral paleomagician to work on some really old cratonic sequences, and come February, work permit permitting (I seriously hope I’m not jinxing this by mentioning it), I’m it. Exotic fieldwork? Check. Potentially interesting reseach? You got it. A chance to escape my current not-so-inspiring job? Woohoo!

This move is not without risks, of course. I’ve gone from a permanent, if degrading, job to a fixed term (one or two years, depending on circumstances and progress) postdoc. Although the guys I’ll be working with seem to have a decent output, South Africa is not exactly the centre of the academic universe. And I’ll be living in Johannesburg, which hasn’t exactly acquired a reputation for cosiness in the past few years. However, I feel that if I turned down this opportunity just because I found the idea a bit intimidating, I’d likely spend the next few years, maybe decades, regretting it. Whatever happens, at least for now I have something to look forward to in 2007.

Whenceforth my blogging?

2006-12-31T18:58:00.000Z

‘Tis the season for navel-gazing, and appropriately enough the New Year also marks the end of a full year of blogging for me (although I first posted to Highly Allochthonous in September 2005, it was not until last January that I started putting a sustained effort into it). Now, therefore seems an apt time to assess how my little project has been going, and where I see it going next.

I’ve managed 112 posts this year – just over two a week. As most of them are reasonably substantial affairs - rather than simply links or clips posted without commentary - I’m happy enough with that level of productivity. With the whole of Earth Sciences to choose to write about, it’s time rather than a lack of material which prevents me producing more, and who knows, as I get better at this style of communication, I might even manage it.

Of course, the great thing about blogging is that I can write about whatever interests me. But more important for me personally has been the fact that in order to write a decent post about something, I need to read and think about the subject a bit – sometimes a lot - more than perhaps I would have done pre-blog. And this attitude is permeating my life: nowadays, even if I don’t end up posting something about it, I find myself looking more into things than perhaps I did before. A healthy attitude, methinks; the only risk is that perhaps I spend more time in front of my computer researching blog posts than is strictly healthy.

Furthermore, as reassurance that this is not just a massive exercise in self-indulgent ego-stroking, my readership, whilst not vast, is growing, and as a nice bonus I have recently picked up some semi-regular commentators. I’ve even attracted my first ~~creationist~~ID troll. It’s quite nice to think that what I’m writing is of some interest to other people, as well as being fun for me.

And as for next year – well, some changes are afoot in my life, which are obviously going to have an impact, but hopefully the blogging will continue.

Philosophia Naturalis #5: Call for submissions

2006-12-30T14:24:00.000Z

On January the 4th, this blog will host Philosophia Naturalis, the physical sciences and technology blog carnival. If you've written something good about physics, astronomy, earth sciences, gadgetry or any other relevent topic, send me a link and share your sciblogging wisdom with a wider audience. Also feel free to share any other good stuff you've found in your browsings. My email address (now in the sidebar) is c.j.rowan * at * gmail.com. Send in your nominations before you get yanked away from the internet and forced to interact with your families, so that we all get a nice treat to recover from the trauma in the New Year.

To those of you with your own blogs - given that HA is not (yet) read by everyone on the Internet, I'd appreciate if you'd cross-post this call for submissions to get the word out a bit further. I'll refrain from threatening cephalopod infants this time...

Note:Using the awesome power of Blogger, this will remain the headline post until after Christmas, and new stuff will appear below it. That's the plan, anyway.

Hold your Martian horses

2006-12-07T23:10:00.000Z

I share Emily’s slight disquiet over the spin applied to the latest (and possibly last) results from Mars Global Surveyer. This is not to say that pictures like this (source) don’t get me very excited:

However, let’s be clear on what we can say for sure. The deposit which appears in the later photo on the top right, and is magnified in the bottom right image, has features very suggestive of fluid-like flow: it appears to be diverted around elevated topography, and fans out at the end. And we strongly suspect that any water on Mars will have very high concentrations of mineral salts, meaning that the lighter colour of the new feature might plausibly be explained by these salts being left behind on the surface when flowing water sublimes away in Mars’s puny atmosphere. However, in the absence of spectrometry to analyse the composition, there are still alternatives to water, such as ~~liquid~~ carbon dioxide, or dust flows.

In the midst of all this excitement I wondered whether there was any more data coming in from MARSIS, the radar instrument on Mars Express. It’s been more than a year since I blogged about preliminary indications of subsurface water ice beneath Chryse Planitia (at mid-latitudes, like the crater gulleys being scrutinised by NASA). Very little seems to have been released since; the only reference I found was a throwaway remark in this nice summary article:

"MARSIS has shown that many of the upper layers of Mars contain water ice," says Jeffrey Plaut of the Jet Propulsion Laboratory, Pasadena, who is the co-Principal Investigator on the MARSIS experiment.

Interestingly, most of the article is discussing spectrometry results which show how early standing water on Mars seems to have been fairly quickly locked away in clay minerals, sulphates, and red ferric oxides. But pure water may still be around, in the form of subsurface permafrost which in some places may be quite close to the surface. The Global Surveyor pictures hint that this arrangement may not be completely stable. And dynamic processes, even on a small scale, are exciting; change leads to disturbances from equilibrium, and interesting chemistry, which are the sorts of things that life thrives on.

Either way, results like this show exactly how the decision to send a succession of probes to Mars to place it under close, continuous observation is paying real scientific dividends.

Two carnivals for the price of one!

2006-12-07T21:27:00.000Z

Dan Collins over at Down To Earth has been enthusiastically earning his sciblogging spurs this week, managing to organise not one, but two, blog carnivals. Go join the grand voyage of discovery that is Tangled Bank #68, or read the latest and best musings on physical sciences and technology at Philosophia Naturalis #4. Or both.

The next edition of Philosophia Naturalis will be hosted by this most 'umble blogger on January the 4th. I'll be sorting out an official call for submissions shortly, but anyone who's particularly keen can send suggestions to me at c.j.rowan *at* gmail *dot* com. Alternatively, go here , where you can also volunteer to host. No signing in blood required, I assure you.

Truth In Science on Newsnight

2006-12-07T12:40:00.000Z

Via Richard Dawkin's website, I've been made aware that Truth in Science recently featured on Newsnight. The clip posted there rather annoyingly cuts off before the end of the segment, but I've found another, full version on YouTube:

The report states that 59 secondary schools (out of 4,230) have accepted the Truth in Science packs, although again there is no indication of how this number was arrived at, or what "accepted" means: wrote effusive thank you note? didn't return it or say they'd binned it? The interview at the end involves Paxman, head of Truth in Science Andy Macintosh, and Lewis Wolpert. I'd love to say otherwise, but Wolpert didn't do very well really. There was lots of huffing and puffing about how "it's not science, it's religion"; this is true, of course, but makes him easy to charicature as a "flustered defender of the crumbling Darwinian Orthodoxy". To be effective in such situations, pro-science people need to stay calm, and focus on getting some important points out to the average viewer:

Scientists have no trouble with criticism of evolution, or any theory - that's how science works, and how it progresses. But we'd prefer those criticisms not be ones that have been shown, time and again, to be flawed. For example, any criticism which rails against "random chance" is not a criticism of evolution, because it's ignoring the 'selection' part of natural selection.
Furthermore, to properly interpret criticism you need a firm theoretical understanding of the theory you're criticising. The level of instruction provided by the National Curriculum is scant enough, without muddying the waters further with pseudoscience that the students are ill-equipped to evaluate rigorously.
And let's be clear - "evolution can't explain x, therefore ID" is not an example of the scientific method in action, and "an unspecified intelligence at some point did something to DNA by some unspecified mechanism" is not a scientific hypothesis. When you make some positive hypotheses about the nature of God- sorry, The Designer- and when and how he has done his designing, and show (by experiment, not assertion) that your hypotheses explain the facts better than evolution does, then biologists might start taking ID seriously.
Please, please stop waffling on about information being separate from energy and matter. Information is a property of energy and matter. It's like saying that you can have "chocolate flavour" without the ice cream.

Sadly, in this case I think the only hit was scored by Paxman when he pressed Macintosh on who he thought the Designer was - and got nothing but weasel in reply.

Spotting geologists in the wild

2006-12-06T10:28:00.000Z

Here is a good place to start for pointers (although the socks+sandals thing is a lie perpetuated by people jealous of the ease with which we get other people to pay us to go on holiday):

Geologists are 'scientists' with an unnatural obsession with rocks and alcohol. Often too smart to do boring monotonous sciences like chemistry or physics, geologists devote their time to mud-worrying, volcano spotting and high-risk colouring in.

One of the main difficulties in communicating with geologists is their belief that a million years is a short amount of time. Consequently, such abstract concepts as "Tuesday Morning" and Lunchtime are completely beyond their comprehension.

To spot a geologist in the wild, look for:
Socks worn with sandals, unless the wearer is German.
Hand-lens, compass, pen-knife, handcuffs etc. tied round neck with string.
Ownership of a pet rock (in the case of palaeontologists, this will be their closest friend).
Overenthusiasm on the subject of dinosaurs.
Someone explaining to airport security that a rock hammer isn't really a weapon.
Takes photos, includes people only for scale, and has more pictures of rock hammer and lens cap than of his family.
Someone with collection of beer cans/bottles rivals the size of his rock collection.
Someone who brings beer instead of water when hiking.
Someone with unnatural amounts of facial hair and wears lots of polar fleece.
Someone whose lunch consists of rocks, instead of ordinary bread.
Someone who consumes tonsil-killing chili for dinner every night of the week, and warms it up in a can on the drill rig engine block.
Often has hair in a pony-tail (this applies to male or female geologists).
Someone who considers a "recent event" to be anything that has happened in the last hundred thousand years.
Someone who licks and/or scratches & sniffs rocks.
Someone who eats dirt and claims to be "getting an estimate of grain size"

Follow the link to the Uncyclopedia, Wikipedia's "very special" cousin, for more. It seems that they recognise the importance of us Geologists in the scientific ecosystem, because as yet only the Physicists have had similar treatment (well, Geographers have too, but we all know that they're wannabes).

Point urgently required

2006-12-05T15:41:00.000Z

Clearly I’m having an off week, because I’m having trouble seeing the logic which justifies a couple of recently announced, grandiose projects:

The maintenance and eventual replacement of Trident. It seems that the UK government is convinced of the worth of our ‘independent’ nuclear deterrent (the White Paper can be found here ), which (a) relies on us renting missiles from the US, (b) at best weasels around, and at worst flagrantly breaches, the Nuclear Non-Proliferation Treaty (either way, we look like hypocrites), and (c) seems unlikely to deter (in the government’s own words) fanatical terrorist groups hell-bent on destroying western civilisation; even if they have state sponsors, are we really going to nuke an entire city of people in retaliation for the secret acts of some members of their government? Ye gods, according to Wikipedia, we are. Ulp.

In terms of unforeseen “conventional” threats to deter, when asked point blank on Channel 4 News last night about exactly which countries might pose a strategic nuclear threat in the future, Defence Minister Des Browne replied (being mercifully succinct by his normal standards) that “we all know who they are.” Colour me unenlightened, then, because I can’t see North Korea or Iran wasting what capability they may eventually develop on us when there are much closer and more obvious targets. Likewise, amongst the present nuclear powers, for India, Pakistan and Israel. This leaves Russia and China (who seem unlikely to want to bomb major export customers back into the Stone Age), France, and the US.

This is beside the point anyway: if we don’t want other people threatening us with nuclear weapons, isn’t saying “erm, actually maybe we should hang on to ours”, rather than working towards disarmament, more likely to produce a world where this becomes a danger? The only true advantage that I can see (beyond keeping our shipyards busy) is that it keeps us on the UN Security Council; but has that exalted position garnered us any real benefit in the last 30 years, beyond being able to fool ourselves into thinking we are still a major mover and shaker in world affairs?
NASA’s moonbase. NASA has announced plans to set up a permanent base on the moon. Leaving aside the question is whether the vast sums being diverted to the Moon, Mars, and Beyond Program is worth losing lots of cool robotic missions (which believe, it or not, is a tough one for me - what breathing geologist would not want the opportunity to swing their hammer on Mars?), what is building a lunar base meant to achieve? Technology testing? I’m not sure that the Moon is such a close match to Martian conditions that it is worth the expense and difficulty. To increase the chances of novel scientific output? We could always do with some more lunar rocks, and the astronomers would also be tempted, but forgive me for being cynical. As part of a long-term strategy of establishing a permanent human presence beyond low Earth orbit? Stop laughing. I fear that this will go the way of the ISS: huge amounts of money in, very little tangible out other than the fact that it exists. You can read more commentary on this at Cosmic Variance.

So what is it with government and their agencies? I doubt I could get one of the funding councils to give me a teeny fraction of the billions these projects are going to eat up without being a lot more specific about exactly why it’s worth it.

British Science Blogging

2006-11-30T18:09:00.000Z

What goes around comes around on the shameless blog-whoring front, I reckon. A positive spin-off from the Truth In Science debacle was the happy discovery of a number of excellent UK, or UK-based, science bloggers of whom I was previously unaware. I’m sure there is more excellent stuff out there, and I’d like to know where it is. So if you write about science and are from or are currently based on this side of the Pond (ex-pats also welcome), link to yourself in the comments and I’ll add you to the list below. Everyone else, tell me about the relevant people in your blog-roll.

The List

Bad Science - Ben Goldacre keeps an eye on the relentless ignorance of the British media. Poor man.
Bunsen Burner. Some excellent general science writing (it’s not been active for a couple of months though).
Connaissances. A geologically-inclined poet currently living in France.
Darren Naish: Tetrapod Zoology. A paleontologist who actually gets to study dinosaurs.
Dr Petra Boynton - an evidence-based approach to sex and relationship issues.
dotdotdot - contrary to the tagline, she apparently does now have a PhD.
El Gentraso - Science writer focussing on evolution, ecology and conservation.
Gooseania - surviving a Maths PhD in Manchester.
homunculus - Philip Ball gets people to pay him to write about science. Bastard.
inkyCircus - Still one third British, which is enough to qualify them for our football team (they'd probably be an improvement too).
Leaves on the Line - Andrew Jaffe, an astrophysicist at Imperial College, London.
The Neurophilosopher’s weblog - cognitive science and other things biological.
Postblogger - biochemist/botanist riffing on the traumas of being a post-doc (except on Thursdays).
Post Doc Ergo Propter Doc - chemistry postdoc, and not afraid to complain about it.
Ramblings of a Scientist - of Dr. Jim, to be precise.
Sane Scientist - not so sure of that myself...
The Scientific Activist - an American biologist in Oxford.
A Somewhat Old, But Capacious Handbag - Miss Prism opines on cakes and biology.
Stoat - climate science commentary.
Transient Reporter - survived British bording school, so academia holds no fears for him.
The Unbearable Lightness of Being a Postdoc - Iknownotwhattodo, another biologist stuck in post-doc limbo.

Keep them coming - then who knows? We can coordinate on any more MP nagging, follow up on Postblogger’s suggestion for our very own carnival, and, more importantly, think about getting together in a pub somewhere…

Link to me or the puppy baby squid gets it

2006-11-30T08:56:00.000Z

People are getting much more imaginative when coercing people to link to them. First we get Acephalous garnering plugs by the bucketloads in the name of science (I’m just hoping that he’s done a control experiment he hasn’t told anybody about), now Transient Reporter is not only begging for comments but getting other suckers to do it too.

Clearly, I need to up my game. I was going to get attention by threatening this sweet little fellow with an ugly demise:

But everyone knows that for the big boys, chordates are so last phylum. So I went down to the waterfront* this morning and took another hostage:

I’m not asking for much in return for letting the little guy to swim free, am I?

Mmmm… kraken crackling….

*look, I know the Solent is thoroughly scoured of all interesting animal life, but bear with me, hey?

Phases of belief

2006-11-30T00:16:00.000Z

I’ve been puzzling over why what is a legitimate dispute between members of the pro-science camp, over emphasis and tone in the struggle against the forces of ignorance, always seems to break down into what could charitably be referred to as ‘arguing past each other’ (I’m not implying the coturnix is an offender here, by the way – he’s just got the best link summary).

A common framing of different theological positions is to represent the continuum from theism through agnosticism to atheism as a change in the relative importance of empiricism and faith in a particular person’s worldview. An atheist places a high value on tangible evidence; a theist is more concerned with the greater truths that they feel exist outside of the world we can subject to experimental verification.

I can see some fairly obvious flaws with this representation. Committed empiricists see all the theists, fundamentalist and moderate, lumped together at the far end of the spectrum, which can make them highly suspicious of someone like Ken Miller, who is clearly a man of deep religious conviction even though he just as clearly values science. Furthermore, as we’ve been so recently reminded, at that empirical end of the spectrum you find people who have little time for faith themselves but will tolerate it in others (provided that religious views are not being foisted too egreriously on the unwilling) jostling for space for people who argue that all faith is silly and even dangerous. The fact that a single axis does not usefully capture the range of viewpoints and how they relate to each other seems to make it all too easy to misunderstand other peoples’ positions.

Because of this, I think a third factor needs to be considered, which for want of a better word I’m referring to as ‘zeal’ (I also considered ‘passion’, which might be a less inflammatory choice). This is a measure of commitment to a particular worldview; how much do you care about it being true? Does it bother you that others don’t share it? Inspired by a recent treatise on ‘thermopienamics’, I’ve tried to map different theological outlooks onto a ternary diagram, with Empiricism, Faith and Zeal as the vertices. The advantage of this representation is that it (hopefully) emphasises that I’m not talking about absolute quantities here, but a relative measure of which attributes most control someone’s positioning in the theological menagerie: someone who plots near the faith vertex is not necessarily antiscientific per se, it is just that faith is far more important to them than empiricism.

In this representation, the Faith/Empiricism side of the triangle is dominated by agnosticism, because they generally don’t particularly care one way or the other about such matters (or at least aren’t too bothered by others disagreeing with them). The boundary between the theist and agnostic sectors reflects the fact that people who are more passionate about their religion can maintain their faith even when they have an appreciable regard for science and empirical reason, whereas less passionate theists are more likely to drift into agnosticism. Likewise, if you tend toward empiricism, the more you care about the existence or non-existence of God(s), the more likely you are to drift over into the realm of the actively disbelieving atheist. I’ve reserved the high end of the zeal realm for cranks and conspiracy theorists, whose passion is tempered by neither faith nor empiricism.

In the next figure, I’ve tried to plot the positions of significant religious denominations and the major players in the recent spat (apologies to anyone who feels misrepresented).

Does this help us any? In my mind, it gives us a new perspective on some recurring problems. For example, the suspicion moderate agnostics seem to have of some of their atheist brethren can be understood to stem from their suspicion of too much zeal for any particular worldview; they feel it is divisive and polarizing. Both fundamentalist theists and the more vocal atheists lie in the same direction in this regard, even though the focus of their zeal is entirely different. This confusion between faith and passion may also be behind the theists’ “atheism is a religious belief too” argument.

Likewise, the snide remarks which sometimes get directed towards “timid” agnostics by atheists also reflects a misunderstanding – if you don’t personally find the existence (or not) of God particularly important, you are probably happy to stick to the more technically correct position with regard to non-corporeal entities that exist outside of space and time: “there almost certainly is no God, but we can never be 100% certain”, to adapt Dawkins slightly. The mainstream Anglican Church - which places great value on thoughtful, less boisterous faith, and is looked on with some contempt by the evangelical wing for just that reason - is more than happy to stick God into that gap, which science may make smaller but can never completely close (listen to the Archbishop of Canterbury talking to John Humphrys, for example). This is as close as you get to the ‘non-overlapping magisteria’ idea in the real world: there is still some overlap, but in practical terms it is very small, and allows people (if they wish) to reconcile their faith with the empirical world. This includes people like Ken Miller (who is, of course a Catholic, but the idea is the same). In contrast, for fundamentalists the magisteria overlap almost completely; because they regard revelation and scripture much more highly than science, in their minds science loses and is denied.

Another interesting feature of this representation is that it suggests that the more zealous theists, if something causes them to doubt their faith, may be more likely to move directly into the atheist camp without any intermediate stops in agnosticism. I think this is interesting in light of the widespread anger amongst the “deconverted” which surprised Dawkins so much on his recent US tour. Perhaps the more zealous Christians are more likely to feel betrayed or lied to if they lose their faith than the former Anglicans who Dawkins would more commonly encounter in the UK, which makes them a bit more passionate in their atheism. And, somewhat heretically, it might suggest that atheists can have a uniquely effective role in the conversation – in supporting and encouraging these refugees.

The other sector I’ve tentatively identified in the middle of the triangle is the realm of the ‘Einsteinian religion’ which Dawkins discusses in The God Delusion - where effectively, ‘God’ is the universe revealed by science, capable of inspiring wonder and awe but not so keen on the smiting or prying into peoples’ personal lives. I’m wondering if this is the true middle ground we should be aiming for – the triple point of the theological system. But for now, if you’re picking sides, by my reckoning I’m fairly sure that a lot of us can pick both (Update: i.e., this whole notion of "teams" is meaningless, there is just a slight difference in the theological outlooks that people are comfortable with - in this particular case I see Ed as uncomfortable with the overly zealous, and PZ as uncomfortable with the overly credulous):

All we need to do is get the moderates to see that a little bit of passion is not always a bad thing, and perhaps get the hardcore atheists to concede that people are always going to believe silly things, but some silly things are more harmful than others, and then we can all be one big happy creationist-bashing family again. Until Christmas, anyway.

Student incoherence

2006-11-28T18:20:00.000Z

I’ve just finished marking some assessed practicals. Personally, I’ve yet to be convinced that formally assessing an exercise where they have three hours to wheedle the answers out of you has much educational value – I’d much rather use the class time to properly consolidate important concepts and then test it with an out-of-class exercise - but hey, I’m not in charge of teaching.

The good news for this year is that, on the whole, the marks were pretty good. Whether this is due to (a) smarter students, (b) A clearer idea of the set task (I’d rewritten the rather opaque set of instructions I inherited last year) or (c) I’d confused them less in lectures, is unclear, but hopefully I can justifiably take some of the credit.

However, a couple of things perplexed or annoyed me. Firstly, the Oceanography students (whose reasons for doing a tectonics course somewhat escape me) scored significantly higher than the Geology/Geophysics students. Perhaps my suspicion that the more sensible geology students prefer to go to proper geology departments has some merit. Secondly, the most annoying aspect of marking this year was the complete disorganisation of the submitted work. Almost universally, the relevant discussion and working for the individual questions were not collated in a sensible order, but scattered randomly throughout the submissions, making it very easy to miss things. It’s a good thing for the students that I was conscientious about checking through a second time when adding up the marks.

I didn’t actually penalise anyone for this, and I’m thinking that maybe I should have –being able to properly articulate your answers is almost as important as being able to produce them in the first place. My worry is that this work was produced under no time constraint, which doesn’t auger well for the exams after Christmas.

Return of the Megatsunami

2006-11-25T17:00:00.002Z

Update: Further developments in this story can be found here.

It seems like megatsunamis are back in vogue, but this time a different culprit is in the frame. Around the turn of the millennium a lot of publicity was given to the suggestion that a 200 cubic kilometre-sized chunk of the western flank of Cumbre Vieja, an active volcano on La Palma in the Canary Islands, was poised to fall into the sea in a future eruption. Modelling suggested such a collapse would send a gigantic tsunami racing westward across the Atlantic, and the eastern seaboard of the US would be assaulted by 50 m high waves that would penetrate up to 20 km inland (for comparison, the Boxing Day 2004 tsunami produced waves 20-30 m high which penetrated 2-3 km inland on the Sumatran coast, a mere 160 km away from the epicentre).

This apocalyptic scenario was put forward by Bill McGuire and his colleagues at the Benfield Hazard Research Centre. McGuire has become the go-to guy when you want a geological scare-quote for your breathless documentary about how we’re all doomed, whether by megatsunami, supervolcano, or some other hyperbolically titled geological phenomenon. Here in Southampton, some people who have studied past collapse events in the Canaries think that the risk is being a tad…overhyped (see also here for the Benfield team’s counterargument, because you seem to get a series of much smaller landslides rather than one big one which will wipe out the whole of Western Civilisation.

Now Phil calls our attention to an article in the New York Times (free registration required) which highlights another potential source for really big waves - oceanic asteroid impacts, which a group of scientists led by Dallas Abbott have proposed as the source of some interesting wedge-shaped deposits, referred to as ‘chevrons’, you find on some shorelines, particularly around the Indian Ocean. Firing up Google Earth, we can find them on the West Australian coast (the line on this and the following images is 5 km long:

and here are the stars of the NY Times article, in Fenabosy bay, Madagascar:

and some similar structures I’ve spotted on the east coast of South Africa:

From a distance the chevrons resemble large dunes, but when you look closer things don’t fit. Studies of the Australian chevrons (see here and here) reveal that although they’re largely made up of sand, they also contain shell debris and cobbles (clasts of rock about 10-20cm in diameter), and sometimes are associated with much larger boulders, which appear to have been transported a considerable distance.

These observations are consistent with the chevrons being formed by a violent surge of water – a storm surge or a tsunami – sweeping the shells and other marine material inland. The strength of current required to transport the large boulders, and the distances inland (several km) and height above present sea level (10s of m) this material now crops out, have led some people to favour a tsunami origin.

So where do the asteroids come in? Look at this animation of the propagation of the Boxing Day 2004 tsunami (for those with lots of bandwidth, go here for the high resolution Quicktime version), and compare the wave directions radiating away from the Sunda Trench with the orientation of the chevrons found around the Indian Ocean. It’s clear that the former cannot cause the latter, so the chevron-causing tsunamis were not generated by subduction zone earthquakes (all of the other plate boundaries in the Indian Ocean are spreading ridges). Even if the orientation wasn’t wrong, the size of wave required to form structures on the scale of the chevrons dwarfs even the tsunami generated by the magnitude 9.2 earthquake two years ago.

Hence we need another source, and Abbott and the other members of the ‘Holocene Impact Working Group’ reckon that source is an asteroid impact, specifically the one which formed the 18-mile wide Burckle Crater, located in the centre of the Indian Ocean (31°S, 61°E). To support this hypothesis, they cite analysis of some of the marine fossils found in the Madagascar chevrons, which are fused with metallic flecks enriched with elements common in chondritic asteroids but rare in the Earth’s crust (as Lab Lemming explains rather better than the NY Times article).

This is not the only recent large impact Abbott and her colleagues have proposed – you can find chevrons on the eastern coast of Australia and southern New Zealand which they’ve linked to a crater on the New Zealand continental shelf. That’s at least two major impacts in the last 10,000 years, which is a bit at odds with the current estimated frequency calculated from astronomical surveys of near-earth asteroids.

In the midst of this contradiction, then, it is worth noting that the evidence is still slightly ambiguous. From the information I can find online there is reasonable evidence that at least some of the chevrons are caused by tsunamis, but the orientation of many of the Australian chevrons seems a little too north-south to be obviously traced back to Burckle Crater, which is almost directly to the east; and in the second of the two papers I linked to above, carbon dating of coral and shell debris in the chevrons suggests that together they record at least three events, roughly 700, 2000 and 6000 years ago - Burckle Crater is thought to be about 5000 years old - rather than one big event, although this may be complicated by reworking of older debris. Perhaps, then, we are looking at evidence for a number of smaller impacts, perhaps mixed in with submarine landslides, rather than a single big one forming all the chevrons. Such an interpretation would probably be more consistent with the astronomical data – there’s probably more uncertainty in impact rates of smaller asteroids, as they’re harder to spot (while we’re on that subject, it seems that estimates of the size of tsunami generated by an impact of a given size vary widely, which introduces additional uncertainties) . However, only time, and some careful dating work, will tell.

Scientific writing for beginners

2006-11-22T09:33:00.000Z

A letter at the core of a recent bruhaha at MIT, where a prospective hire was caught in the cross-fire of egos higher up the academic food chain (see Adventures and Ethics in science for analysis and links to more), has been brilliantly dissected by wildtype over at Transient Reporter. It's all good, but this bit is a particular favorite with me:

I am most happy to support you if you and I are going to work with some distance between us.
Stay where you are and I won’t cut your grant proposals down during study sessions, or hold up your manuscripts.

because it is a prefect illustration of scientific writing, where withering intellectual assaults (as well as speculative handwaving) are deeply buried beneath a veneer of understatement and superficial politeness. As a semi-homage, I thought I'd reproduce a handy translation guide for certain key phrases in scientific papers, which I originally put up on my now defunct pre-blog website. It dates from those heady undergraduate days when I read many more papers than I have time to now.

A novice or outsider might expect the average scientific paper to be a clear and coherent document. Far from it. Little research produces clear-cut or easily understandable results (it would be quite dull if it did), but a combination of ego and desire for further funding means that few scientists will readily admit this. Fortunately for them, the somewhat formal prose traditionally used in a publication provides many opportunities for deliberate obfuscation (as well as the lobbing of a few choice insults at people who happen to disagree with you).

The list below exposes and translates some of the more common phrases you're likely to find.

"It has long been known"	I didn't look up the original reference.
"A definite trend is evident"	These data are practically meaningless, even when you squint.
"Whilst it has not been possible to provide definite answers"	An unsuccessful experiment, but I still hope to get it published.
"Three of the samples were chosen for detailed study"	The other results didn't make any sense.
"Typical results are shown"	These are the only results which prove my theory.
"These results will be in a subsequent report"	I might get around to this sometime, if pushed/funded.
"In my experience"	Once.
"In case after case"	Twice.
"In a series of cases"	Thrice.
"It is believed that"	I think.
"It is generally believed that"	A couple of others think so, too.
"Correct within an order of magnitude"	Wrong, but I'm not going to admit it.
"According to statistical analysis"	Rumor has it.
"A statistically-oriented projection of these findings"	A wild guess.
"A careful analysis of obtainable data"	Three pages of notes were obliterated when I knocked over a glass of beer.
"It is clear that much additional work will be required before there is a complete understanding of this phenomenon"	I don't understand it. AND/OR Give me more money.
"After additional study by my colleagues"	They don't understand it either.
"Thanks to Joe Bloggs for assistance with the experiment and to Cindy Adams for valuable discussions"	Mr. Bloggs did all the work, and Ms. Adams explained to me what it meant.
"Contrary to the interpretation of Jones (1997)"	Jones is an ignorant fool.
"A highly significant area for exploratory study"	A totally useless topic selected by my committee.
"It is hoped that this study will stimulate further investigation in this field"	I quit.

Of course, these rules sometimes break down - in print, most often in the 'Comment and Reply' section. This is one of the more formal ways that peer review continues long after publication - people who disagree with you, or want to engage in a bit more cite-napping (I do like that term), can submit a short rebuttal to the publishing journal, which is published together with any response (re-rebuttal?) you might have. Outbreaks of 'contrary to the interpretation of' are common, but I am especially reminded of a particular response, which pretty much dropped all pretense at politeness:

Westaway [2004] adds details on the deformation rates in the eastern Mediterranean that do not affect the results of our paper, and need no further comment. He is wrong in saying we suggest no surface uplift of the Turkish-Iranian plateau or Greater Caucasus since 12 Ma, and we refer readers to sections 4 and 11 of our paper for the details [Allen et al., 2004]. We do not cite Westaway's papers on lower crustal flow because we do not believe them and see no need to refer to them: He suggests crustal flow from areas of thin crust to thick crust, against the gravitational buoyancy forces. Our reply is brief because we do not think this was a constructive comment on our paper, and not worth a response on the same scale.

Ouch.

My democratic experiment concludes

2006-11-21T22:49:00.000Z

...and, I have to say, the result is surprisingly positive. As promised in his last response, I received a follow-up letter from my MP John Denham, which I reproduce below. Bolded words were underlined in pen in the original.

Thank you for contacting me regarding the "Truth In Science" resource packs.

Neither the Department for Skills and Education nor the Qualifications and Curriculum Authority (QCA) have been involved in the development or distribution of the "Truth In Science" resource packs to schools.

It is up to schools to decide what teaching resources they need to help them deliver the national curriculum. However the Minister agrees with you that the "Truth In Science" information is not a suitable resource for the science curriculum.

The programme of study sets out the legal requirements of the national curriculum. There are two programmes currently operating in key stage 4 sciences:

Pupils in year 11 are following the 2000 programme of study
Pupils in year 10 are following the 2006 programme of study

Both programmes include a focus on the nature of science as a subject discipline including what constitutes scientific evidence and how this is established by experimentation. Pupils also learn about scientific theories with extensive supporting evidence from established bodies of scientific knowledge.

The Minister would like to assure you that he is working with the QCA to find a suitable way of communicating to schools that the "Truth In Science" is not part of the science national curriculum.

Yours sincerely,

For non-Brits, Year 11 are 15/16 year-olds (the last year of compulsory education, at the end of which the students sit GCSE exams), Year 10 are 14/15 year-olds. Follow the links to compare the relevent parts of the 2000 programme of study, and the 2006 version. The troubling section 1 b) is being changed significantly in the newer standards, which is in itself somewhat reassuring.

When I started this little experiment I was not exactly optimistic about a positive outcome - but I have been very pleasantly surprised. Not only did my MP acknowledge my communications, but he actually took action based on my concerns. Even better, it seems that those in a position to actually do something are aware of and concerned about the actions of Truth In Science (lets just hope that they don't have to run it past the PM first). This is more due to the efforts of others, I suspect, but every little helps, and this whole episode demonstrates that, through tools like writetothem, it isn't hard to supply that little.

Although the experiences of others show that I may be quite lucky to have a conscientious and savvy MP (he's even started a blog specifically to get feedback from his constituents), I find myself in the happy position of having had a cynical prediction - about politics, no less - proved wrong. In my next post: gravity defying pigs.

Update: Unbearable Lightness has also got a positive response; postblogger is still drumming his fingers, and has finally named and shamed his rather up-of-himself MP.

Ego boost

2006-11-21T22:12:00.000Z

A recurring referral in my sitemeter log indicates that I've been nominated for an award. I'm flattered to find myself in some pretty distinguished company, which means that I've not a hope in hell of winning even if the nomination goes forward - unless PZ and Phil really go at it in a tentacles vs telescopes deathmatch...

Real peer review

2006-11-15T23:29:00.000Z

Peer review is the sacred core of the self-correcting machinery of science. Before it can be published, a new paper must pass muster with qualified experts in the field it covers, ensuring that dodgy results and poorly supported conclusions do not make it out into the literature to impede the grand progress of the scientific enterprise.

Well, that’s the theory – but what’s it like in practice?

A source of constant amusement (and some trepidation) to me is the way that some of the most vital jobs in your academic career seem to be just dropped into your lap: you are asked, told, expected to do them and do them well, but no-one thinks to provide much in the way of guidance, or even check that you’re vaguely competent, before gladly dumping the workload in your lap*. That’s certainly been the case for lecturing (for instance, no-one on the teaching staff has ever bothered to sit in on one of my lectures to see if they are actually coherent), and my introduction to the ‘review’ bit of the peer review process has been suspiciously similar. My two helpings of review fodder to date, the second of which I polished off yesterday, have both come to me in the same way - the editors sent a paper to my supervisor/boss and he fobbed them off in my direction (so that’s exactly like the teaching then...). Whether their eagerness to do so was confidence in his opinion (scary) or desperation (scarier) is hard to tell.

That’s the first dose of reality – willingness to review other papers is a grudging quid pro pro for other people reviewing yours, and the abstract realisation that we have to do it to make the system work isn’t much of an incentive when you have other, more concrete, demands on your time. This is especially true for the people most frequently solicited for reviews - prominent scientists at the forefront of their field, who want to spend their time staying at the forefront rather than carefully checking the work of current or potential competitors. Hence, with one important exception, one of three things will happen:

They review it by skimming the paper and banging off a few line which quote your abstract back at you, and say its all fine. A nice ego boost, but hardly constructive.
They stick it in their in-tray and leave it there for 5 months**.
They offload the task onto a lesser minion (sometimes promptly, sometimes only after nagging by the journal editor, if they are still too busy to bang out the cheap and cheerful review described in (1)).

The second dose of reality comes when considering the exception, which is when the submitted paper treads on the toes of one of the reviewer’s pet theories, or (worse) pre-empts something that he is working on himself. Whilst such situations can motivate a prompt review, they can also lead to the concept of objective assessment getting a little…strained, meaning that such a review is going to have a strong focus on the negatives. Common examples: a minor problem is talked up as a fundamental flaw, or an unrealistic amount of extra analysis is demanded (a hostile reviewer for one of my papers suggested that to properly establish one of my ‘assumptions’ – in reality the major conclusion to the paper - I would need to undertake elemental analysis of every Miocene outcrop in New Zealand). And as Lab Lemming astutely reminds us in the comments, even where your reviewer is managing to quell the urge to trash your work, you're still liable to an unhealthy dose of cite-napping: it seems that somehow you've missed the key contribution of every paper they've written since 1977, and it's their duty to point this out to you.

In the former case this can be annoying, but is to a certain extent healthy – who better to test your ideas to destruction than someone not inclined to believe them? The problem is that papers within a given subfield tend to always get sent to the same people, meaning that if they are hostile to certain ideas or interpretations, it can be very difficult to get them published in a top journal. However, even if publication is slowed by such antics, good science will generally out in the end. The latter case is more difficult, because it is not altogether unheard of for someone to hold up someone’s paper while manoeuvring to scoop it, especially in competitive fields like paleoclimatology***. And then, basically, you’re shafted.

All things considered then, since anyone more than a year into their PhD should have had a healthy amount of practice at critically assessing the scientific merit of a paper (I’ve been scribbling sarcastic comments in the margins since my undergrad days), delegation is perhaps the best outcome; indeed, for lesser lights such as myself the novelty value of actually being asked for my opinion probably motivates us to be more conscientious, compensating for our relative lack of experience (I may generalise too much here, given that my pedantic nature forces me in that direction anyway). Now, however, the problem is reversed, because the reviewer finds himself in the position of passing judgement on the work of people who are far more important than he is. A glorious victory for egalitarianism, to be sure, but should you identify any serious flaws you have to bear in mind that in the small world of academia, just because the review process is supposedly anonymous doesn’t mean they won’t find out it was you who trashed their precious paper. You have to choose your words carefully, and even then some people may not be too happy with you, should they find out who you are.

Hopefully, it won’t come as too much of a surprise that scientists are human beings, and thus the peer review process is witness to as much sloth, incompetence and back-stabbing as any other human activity. The question is, how much does it matter? The trumping issue aside, not as much as some people think. The ‘official’ peer review process is really just a preliminary; the real peer review occurs after publication, when everyone gets to see your opus, read it, write sarcastic comments in the margin, and (if it’s any good) use and cite it in their own work. This is something that ID ‘theorists’ and other pseudoscientists constantly misunderstand: somehow getting a paper ‘peer reviewed’ and published does not automatically convert bad science to good. It might make scientists pay some attention to your ideas, but it doesn’t require them to agree that they are valid; and if they don’t think they are, they will say so. Good ideas are good ideas and bad ideas are bad ideas, whether they’re ‘peer reviewed’ or not, and will gain traction – or not - accordingly. However scientific publishing adapts to the internet age, whether with “open reviews” or some other system, that will always remain the real test

*This is my experience, anyway – I’d be interested to whether this is actually fairly common, or my department’s unique approach to training is shining through.
** Yes, I’m talking to you, the JGR reviewers who have been sitting on a couple of my papers since June…
*** Which might explain why so many of the paleoclimatologists I’ve met are constantly in a bad mood.

Where have all my pictures gone?

2006-11-13T18:26:00.000Z

I've just realised that one of the webhosts I use to host some of the images used on this blog (I don't host them on Blogger much because (a) you can't list them and (b) it converts everything to crappy jpegs) has seen fit to erase everything from my account space. Without warning. I don't know how long its been since this happened, so apologies to anyone who's been image-less (although it's partly your fault for not telling me).

I've restored all of the broken images I've found bar one (the Java strain partitioning figure, which I'm going to have to redraw). Let me know if you find any more. I'm off to find an e-mail address which I can impotently express my displeasure at.

Earth – dwarf planet

2006-11-13T17:27:00.000Z

I’m somewhat chagrined than I didn’t pick up on this myself, but I’m amazed that no-one else did: in all the furore over whether Pluto was a planet or merely a borrowed geological term, no-one stopped to think of the nominative consequences for our own fair sphere. Anjana Ahuja reports in The Times on the views of the editor of Sky and Telescope magazine, Richard Fienberg:

According to the IAU’s General Assembly, which met in Prague this year, a celestial body can be called a planet only if a) it is in orbit around the Sun; b) it is round (in other words, is massive enough to be shaped into a ball by its own gravity); and c) it has cleared the neighbourhood around its own orbit.

It is c) that has proved awkward. The IAU meant that planets should orbit the Sun in isolation, rather than whizzing around with other bodies, such as asteroids. This clause did for Pluto, because it resides in the Kuiper Belt, a girdle of icy bodies that lies beyond Neptune.

But, Fienberg points out: “Our own world is threatened by . . . a host of other near-Earth asteroids whose paths around the Sun intersect ours. By strict application of the IAU’s new rules, this means Earth is no longer a planet either. Ditto for Mars, Jupiter and Neptune, all of which are accompanied in orbit by little asteroids. Ridiculous!”

Special plead your way out of that one, IAU. I confidently predict the appearance of a modified sub-clause which defines 'cleared' as 'not having any other bodies above a certain percentage of the size of the candidate planet' – if there isn’t one already. It’s not so much I’m convinced by this argument, but it just shows how easy it is to tie yourself in knots when you start preferring semantics to science. And this closing line is priceless:

Fienberg has come up with a fresh mnemonic, forged in pure bitterness, to describe the new Pluto-less planetary octet: Many Very Egotistical Malcontents Just Screwed Up Nomenclature.

Carnival(s)!

2006-11-10T11:37:00.000Z

Edition #3 of the physical sciences carnival Philosophia Naturalis is up at Geek Counterpoint. Lots of interesting stuff there - and I'm not just saying that because my Hawaii earthquake post is included.
The new installment of the more venerable Tangled Bank is also up over at Easternblot.
And it seems there's enough cool anthropology stuff out there in the blogosphere to merit a dedicated carnival - The Four Stone Hearth - three stones of which are currently piled up at Afarenis.

Nuclear seismology

2006-11-09T14:30:00.000Z

A barely remembered anecdote, the recent talk of detecting nuclear explosions, and a Web of Knowledge search combined to bring this paper up on my screen:

Seismic tomographic inversion of Russian PNE data along profile Kraton [1]

The acronym ‘PNE’ is made more explicit in the next result:

Origin of upper-mantle seismic scattering – evidence from Russian peaceful nuclear explosion data [2]

That’s right – PNE stands for ‘peaceful nuclear explosion’, a phrase from a simpler time when people seriously advocated using nuclear explosives to dam rivers, create new anchorages, and release gas from underground reservoirs (which, shockingly, turned out to be radioactive). Both the USA and USSR engaged in this interesting pastime, but the Soviets detonated 239 PNEs against the Americans’ 28, a disparity that is probably due more to the relative power of each country’s citizenry (I suspect even in those days. if given the choice very few people would fancy a close-up view of mushroom clouds) than a difference in official enthusiasm.

Anyway, it seems some Russian geologists had the bright idea of using PNEs to undertake controlled source, wide-angle seismology on a scale not achieved before or since. They arranged to have a series of nuclear explosions set off along a number of lines (with names like 'Quartz' and 'Kraton') stretching several thousand kilometres across the USSR, along which they also deployed seismometers. Unlike reflection seismology, where only the reflected seismic energy coming directly upwards from buried discontinuities such as boundaries and faults is collected, wide-angle seismology deploys seismometers a long way from the source in order to pick up refracted seismic energy; because the speed of sound generally increases with greater depth (and pressure) in the Earth, due to Snell’s Law of Refraction downward-travelling waves eventually curve back upwards towards the surface. If you get far enough from the source, not only will a seismometer pick up these deep-diving waves when they reach the surface, but because of their higher average speed these waves will actually reach that seismometer before ones that have travelled at shallower depths. The distance from the source at which the ‘first arrivals’ from different depths first appear provides a great deal of information about the velocity structure, and hence the physical structure, of the subsurface rocks along the survey line (simply put, earlier appearance of deep waves=faster velocities – although obviously it’s a bit more complicated than that, especially when you factor in the presences of sharp discontinuities in wave-speed across lithological boundaries).

Methodology wise, there is quite a large overlap between these wide-angle techniques and earthquake seismology. However, because the source in this case is man-made, you minimize some of the major uncertainties which limit resolution when your source is a natural earthquake: the exact time and location that the source wave was generated, and the nature of the original signal (as I’ve discussed in the context of the North Korean test, man-made seismic signals are generally much shorter and simpler than an earthquake signal). The frequency of the signal is generally higher, too, which also improves resolution. There is however, one major drawback: the airguns (or less commonly nowadays, conventional explosives) used in seismic experiments produce orders of magnitude less energy than an earthquake does, meaning that pretty much all of the waves penetrating below the crust-mantle boundary (Moho) –about 35-40 km below the surface in normal continental crust - dissipate before they can get back up to the surface. The figure below shows the inferred paths of seismic waves picked up along a wide-angle survey line in the Aleutian Islands (the source is located in the centre, the scales are in km) [3].

Whatever your feelings about the rationality of using nuclear bombs in this way, you can’t deny that they’re going to generate a hell of a lot more energy, allowing signals from deep in the mantle to be received back at the surface. Here’s a similar figure for the ‘Kraton’ PNE seismic line (from [1]. Note the change in horizontal as well as vertical scale: whereas seismometers 2500 km away from the source are fairly pointless for normal wide-angle surveys, for a PNE shot this is about the point that first arrivals from the 660 km discontinuity start arriving. Which I can’t help being a little bit impressed by.

The second of the two papers I’ve cited concentrates on the uppermost mantle, 100-200 km beneath the Earth’s surface. The waves travelling through this region appear to be travelling slower than in the overlying rock, and are also being scattered a lot, resulting in noisy first-arrivals data (the relationship between the arrival time and the distance from the explosion is not linear). The authors propose that this is because the mantle at this depth is partially molten. It seems that the unique data generated by these 30-40 year-old experiments is still reaping dividends, now that scientists worldwide can access them and apply the latest processing tricks.

References
[1] L Neilson et al., Geophysical Research Letters 26(22), p 3413-16, 1999.
[2] L. Neilson et al., Geophysical Journal International154, p 196-204, 2003.
[3] D Shillington et al., Geochemistry Geophysics Geosystems 5, Q10006, 2004 [doi]

Lego weapons redux

2006-11-07T10:25:00.000Z

This must be a real pain to reload...

My democratic experiment continues

2006-11-06T10:09:00.000Z

In slightly more encouraging news, I received a response to my e-mail to John Denham about the activities of Truth In Science. I reproduce it below:

Thank you for your email asking me to sign EDM 2708.

Although Early Day Motions can be a helpful expression of back bench parliamentary opinion, I feel that they are somewhat over used and their impact somewhat diluted. For this reason I only very occasionally add my name to EDM's.

Nonetheless your letter has prompted me to consider the issues you have raised carefully and I have therefore written to the relevent ministers on your behalf.

I will contact you as soon as I receive a detailed reply,

Yours sincerely

JOHN DENHAM MP
SOUTHAMPTON ITCHEN

Well, it's slightly up on 'John thanks you for your interest and will take the matter under consideration', but it still has a slight form letter quality to it, doesn't it? It's a little disappointing that he won't sign the EDM, but the fact that he has forwarded my concerns up the chain of command means that my letter pretty much had the desired effect. Besides, I can see his point - EDM 2708 has collected 39 signatures so far, which isn't nearly enough to make it stand out from the crowd, and his spell as a government minister (before resigning over the Iraq War) has possibly given him some insight into how ~~much~~little EDMs actually register at the highest levels of government.

So, a cautious thumbs up to my local MP; it will be interesting to see what, if any, response will be forthcoming from 'the relevent ministers'.

Update: I’m not the only one who’s been writing to their MPs about this, and via Pharyngula, I see that Postblogger is currently leading the ‘most unhelpful response’ category: his un-named (Tory?) MP responded with

I would be very happy to act on this matter as soon as you can prove beyond all reasonable doubt that Creationism is not true, and I look forward to hearing from you as soon as possible.

Two apparent successes though: Mark Frank’s MP Sandra Gidley, a Liberal Democrat, told him she was signing up (although she’s yet to appear on the on-line list of signatories), and outeast seems have had a hand in getting Liam Fox to sign (as he’s the Shadow Defence Secretary, we can safely say that not all Tories are with the forces of ignorance on this one). I’d be interested to hear of any other successes or failures, which I'll add below

Sharon Hodgson (Labour) at prompting of Jim Windram.

Tony Blair likes science, but he doesn’t understand it

2006-11-04T10:43:00.000Z

Not, at least, if this interview with New Scientist is anything to go by (there’s even a podcast if you want to hear everything, and discussion continues at the New Scientist newsblog). The interview starts with Mr Blair telling us that he was ‘very poor at science at school’, and has only really started to appreciate its importance after he became leader of the Labour Party and PM. Sadly, it quickly becomes apparent that this appreciation is limited to the economic benefits. In a series of questions, the interviewer, New Scientist Editor Jeremy Webb, gives Blair numerous opportunities to exhibit some understanding of science as a process of discovery, but he doesn’t get very far. Here’s the best we get:

How do you bridge the gap between science as an academic interest-discovering more about the universe-and science as an commercial enterprise?

You need a certain amount of pure research, and the excitement and creativity of scientific discovery. But if you also have universities and research centres sufficiently in tune to what is going on in the private sector, then hopefully discoveries will be made that have a real utility.

I actually have few problems with a political leader wanting to maximise the practical and economic benefits of cutting-edge research; what does concern me about this exchange is the Prime Minister’s apparent conception of ‘pure research’ as a nice add-on to the scientific enterprise, rather than its foundation; the most novel, and therefore valuable, innovations are generally unexpected spin-offs from untargeted research into general problems. As an example, who would have thought that studying bacteria which live in hot springs would eventually lead to PCR?

Far more disturbing, however, are the later parts of the interview, which show that this misunderstanding is merely an expression of a much deeper malaise: Blair doesn’t get science as a way of thinking. Take this suggestion that scientists should pick and choose their interventions:

My advice for the scientific community would be, fight the battles you need to fight. I wouldn’t bother fighting a great battle over, say, homeopathy. It’s not going to determine the future of the world.

That’s right: we should just ignore the fact that homeopathy is rubbish. We should stay quiet while practitioners both cynical and deluded convince people to accept comforting myths (you don’t need nasty drugs to get better, just specially treated water!) in preference to reality, promote anecdotal and testimonial evidence over properly controlled experiments, and assert unopposed that the products of modern science are ‘unnatural’, and that its practitioners are either blinkered or corrupt. And then we should wonder why they don’t accept our arguments that the MMR vaccine doesn’t cause autism, that GM food is safe to eat, and that we are going to have to seriously change our lifestyles to prevent catastrophic climate change.

Despite his assertion to the contrary, I think Tony Blair still sees science as ‘something that the “boffins” do’. It’s not. In the modern world everyone needs the informed scepticism of scientific thinking in their mental toolkit. People need to be encouraged to rigorously test their opinions against the ultimate arbiter, reality, and be open to refining them when the facts require it; to not take assertions at face value, no matter how charismatic or authoritative the proponent; and to be aware of the biases and prejudices which can cloud their perceptions. Believing that homeopathy is a valid ‘alternative’ to modern medicine is anathema to this kind of thinking, an indicator that people have, at best, a poor grasp of science, and are therefore unlikely to come to informed and rational opinions on other scientific issues; at worst, they are suspicious of and even openly hostile to phrases like ‘scientific consensus’. How can we not fight to correct that?

Blair expresses a similar attitude with regards to the teaching of creationism, it’s not a problem really, not a battle we need to fight:

This can be hugely exaggerated. I’ve visited one of the schools in question and as far as I’m aware they are teaching the curriculum in a normal way. If I notice creationism become the mainstream of the education system in this country then that’s the time to start worrying.

Sorry, but this is weasel. I don’t care if they’re being subtle about it, I don’t care if it’s just a few faith schools or academies: anywhere where creationism is taught in science class, you mangle whatever meagre understanding of science, and scientific thinking, that person might have got out of our education system. The present situation is worrying; when it becomes mainstream, that’s when you emigrate, because (as others have rightly opined) it’s too late.

I’m sure it’s completely coincidental that these comments come in the face of heavy criticism of the government’s recently implemented policy of labelling homeopathic treatments as if they’re real medicines (which is rather handily smacked down by Sarah over at Bunsen Burner), and their current evangelism for faith schools and letting suspected creationists fund new academies. And that Blair’s suggestions of important issues where he thinks scientists should engage the public – climate change and genetics – are the ones where scientific opinion tends to chime with government policy. The Prime Mininster is betraying his legal background: contrary to his enthusiastic noises, he does not seem to want a electorate that is truly scientifically literate, but one that will accept scientific authorities as expert witnesses in support of government policy.

Sadly, he doesn’t seem to realise the inherent danger in the idea that you can selectively use science to support the ideas that you agree with, and ignore it when it conflicts with them; if you pick and choose, what’s to stop other people doing the same – and choosing differently? That, Prime Minister, is the essence of antiscience.

THC not as weak as we thought (most of the time)

2006-11-02T00:02:00.000Z

Following up from last month, the first results from the real-time monitoring of the thermohaline circulation were presented by Harry Bryden at the RAPID conference in Birmingham last week. I wasn’t there, so you should go to RealClimate and read Gavin’s analysis, as he was. This quote sums up the major news:

There were two key observations: first, that the approximations that had been used in the Bryden et al study were actually valid, and secondly, that the variations day by day varied by around 5 Sv (1 Sv is about 10 times the flow of the Amazon). The mean over the year for the MOC was 18 Sv.

It seems that over timescales of a few days there are fairly sizeable shifts in the amount of North Atlantic Deep Water (NADW) crossing the 25^oN transect. These results pretty much destroy any hope of extracting any meaningful long-term trend from the existing data set of decadally spaced, one-time snapshots of the circulation; the ‘weakening’ from 23 to 15 Sv since 1957 proposed in Bryden et al.’s Nature paper last year is very close in magnitude to the observed natural variability (and their 2004 hydrographic section underestimated the average strength of the present circulation by 2 Sv). In an interview with the BBC, Bryden still seems fairly convinced there is some weakening of the circulation (by 10% in the last 25 years rather than 30%), but I think the jury’s out on even that at this stage.

I’m wondering whether Nature is going to follow up on the fact that one of their headline papers was a little premature (no luck so far...), but as Gavin points out, the media seem to have missed the down-sized estimate in their excitement over the curious 10 day period in November 2004 when the southwards flow of NADW was weak to non-existent (see here, for example). According to someone else I know who attended the talk, Harry Bryden ‘just dropped this in’, and it’s certainly not in his abstract. Why? Because at the moment no-one really has any idea how this could happen. To understand the confusion we need to look a little further north. NADW is principally formed by cold saline water sinking in the Norwegian Sea, but as the figures below shows, the route south is not simple, because it’s path is along the seabed is blocked by the Greenland-Scotland Ridge (GSR), part of the volcanic edifice which Iceland sits atop of. The top figure[1] shows how the GSR acts as a sort of dam, with three or four ‘sills’ at bathymetric lows acting as spillways which spilt the NADW into different currents. The bottom figure [2] shows how these currents all join back together at the southern end of Greenland and head south as one big water mass.

Why is this important? It means that the apparent shut down of the THC is not because there was a temporary hiatus in NADW production (due to, say, freshening of the surface waters due to particularly strong seasonal melting in the Artic). The different routes taken by the NADW over the GSR all take different times, so any cessation in downwelling would not simultaneously cut off all the currents coalescing south of Greenland. There will always be some water. So, if this is a real signal, the whole water mass seems to have somehow been held up in the northern Atlantic somewhere, which seems a little weird. We scientists like weird, or course, but at this stage we need more data: how often do these ‘mini-shutdowns’ happen? Are they seasonal/cyclical or random? I think much more interesting stuff is going to come out of this array over the next few years – not least a robust estimate of the longer term trends in the circulation.

Newer developments:
The Case of the THC "Shutdown"

[1] From Wright & Miller (1995), Paleoceanography 11(2), p157-170.
[2] From Dickson & Brown (1994), JGR 99(C6), p12319-41.

Glass house shatters due to mass casting of stones, more at 11

2006-10-27T12:22:00.000Z

I’ve been meaning to mention the report released last week by the Environmental Change Institute, which argues that the government’s policies for the expansion of air travel rather get in the way of their attempts to seriously curtail CO2 emissions (click here for pdf). However, the lack of any substantive response from the government (at least, I didn’t see one) meant that beyond agreeing that all the sound and fury about nuclear generation (or not) is beside the point if we don’t hit the other areas of our energy use – a point that I’ve made myself before – I didn’t have much to add.

However, I think another story, which has been gathering momentum in the media over the last few days, gives us all something to consider. It involves my place of work. From here:

The National Oceanography Centre in Southampton is home to a £20 million research program on the dangers of rapid climate change. It also houses the southern office of the Tyndall Centre for Climate Change Research. But while its staff are investigating the impact of carbon emissions on our climate, their bosses enjoyed a trip to America with their wives last weekend on a private jet.

Ed Hill (Director of the Centre), Andrew Roberts (Head of the University of Southampton School of Ocean and Earth Sciences) and Bill Wakeham (Vice-Chancellor of the University) flew from Southampton to North Carolina with various other hangers-on. Their private jet was provided by an American businessman that they were courting (and presumably they did not want to offend this would-be philanthropist by insisting on taking scheduled flights) [this is incorrect –see below]. As a result, their journey put several times more carbon per passenger into the upper atmosphere than using a regular airline.

Several staff that I have spoken to from the Centre who are working on the dangers of climate change feel betrayed by this affair. The "do as I say, not do as I do" example of the their bosses undermines their credibility when highlighting the need to reduce carbon emissions. It also hands ammunition to those denying climate change and suggests that the principles of those involved are for sale to anyone who offers to write a cheque.

Indymedia also has an update to this story – surprisingly, I can’t find much else online, although there is a discussion at Stoat.

In public relations terms, this is a complete own-goal, and it’s very easy to take the self-righteous line being adopted by most of the reports I’ve seen or heard about (the second Indymedia link being a good sampling of the general tone). I’m hoping some of them at least got the facts straight - the purpose of the trip was to set up a long-term ~~research~~ teaching collaboration with the University of North Carolina, and the use of the jet was offered by an existing benefactor. So it was a serious visit with a serious purpose. That doesn’t automatically make it all ok. But imagine: you have to go to an important one-day meeting in America. To get to the place it’s being held at, you have the option of paying to go on scheduled flights, with at least one tedious change (and US Immigration, Customs, and Security doing their darnedest to make you miss your connection), or basically going straight there for free on a private jet. Which would you choose?

More prosaically: you have to go to Edinburgh for a couple of days next month. You look up train fares from Southampton, and find a return costs £114.00. You can fly from Southampton airport, in far less time, for £65 (I’ve just looked up these prices). Which would you choose?

In the context of this post, most people would probably plump for the more environmentally friendly options, but I’m honest enough to admit that if I didn’t think anyone was looking, I’d be sorely tempted by the option that got me there cheaper and faster. I would definitely feel bad about it at some level, but that might not stop me doing it. And herein lies the problem we face. The Environmental Change Institute’s report highlights but one facet of what is a pervasive feature of modern life: the environmentally ‘bad’ options are the easy and/or convenient and/or accepted ones. Absurd as it seems, you can get around the UK fastest and most cheaply by flying; imported vegetables in Tescos are cheaper than the ones grown locally; you can have a cheaper (and sunnier, probably) holiday by flying to Spain, or further, than you can in the UK; and, in most places, it is easier and cheaper to drive to work than get the bus. Those who try hardest to reduce their environmental impact – by not owning a car, not going abroad for their holidays - are also viewed as slight eccentrics. It is only when these circumstances, and attitudes, begin to change that we have a hope of getting a grip on our greenhouse gas problem.

Returning to the NOC story, then, the question here is not about private jets, but whether a face-to-face meeting was required in the first place. And if the current furore was not being fuelled as much by reverse snobbery and envy as real environmental concern, that is the question that people would be asking.

Back on the hamster wheel again

2006-10-24T14:47:00.000Z

Last week, everything suddenly went mad as the new semester swung into gear. Current things on my plate:

I’m currently occupying two double lecture slots on Monday and Tuesday mornings. This means preparation is eating my weekends, and I don’t feel good for much mid-week. My view of my performance thus far: ‘not great, but better than last year’. I’d probably be quite negative if I didn’t have last years’ for a reference point, but my pacing is much better this time round, and I feel that most of the time I’m being more coherent (though that remains to be proven…). I am, however, rueing the fact that my original plan to do some serious reading and rewriting over the summer fell by the wayside.
Last week also saw the first arrival of mapping projects on my desk, as the efforts of the 3rd years I went out to Spain in July with were handed to me for preliminary marking. There’s not as many as last summer (thank goodness), and it was only field slips and notebooks at this stage. So, was any of the advice I’d given them was taken on board? Not as wholeheartedly as I would have liked – for example, while everyone had drawn boundaries on this year, a slight lack of thinking was indicated by the fact that they weren’t always sensible boundaries. Oh well, it’s a start; I’m meant to be supervising the write-up too, although if last year is anything to go by my services will only be called upon the day before the hand-in date, when it’s too late to help them.
Somehow, despite not actually volunteering my services, I’ve found myself co-supervising a number of undergraduates whose research projects involve heavy use of the magnetometer, and consequently hand-holding by me. Since things I never agreed to do materialise on my desk with depressing frequency, I’m not overly bothered – I’ll save that for when I have to explain data analysis for the 27th time without any indication that the previous 26 attempts even registered.

Hmm, remind me again – I’m being employed as a technician, right?

A little experiment in democracy

2006-10-19T21:45:00.000Z

Via Pharyngula, I've learnt that an Early Day Motion regarding the activities of Truth In Science has been tabled in Parliament:

That this House shares the concerns of the British Centre for Science Education that the literature being sent to every school in the United Kingdom by the creationist religious group Truth in Science is full of scientific mistakes and fails to disclose the group's creationist beliefs and objectives; and urges all schools to treat this literature with extreme caution.

It seems that the British Centre For Science Education was involved in the tabling of this motion; as they caution when talking about this on their website, no matter how many MPs sign up, it is unlikely to trigger a full Parliamentary debate; but a large number of signatories may allow an EDM 'to impinge on Cabinet conciousness'. So, following the example and suggestions of some of the Pharyngula commentators, I went to writetothem.com and sent the following to my local (Labour) MP:

Dear John Denham,

I was wondering if you are aware of the activities of a creationist group going by the name of 'Truth in Science', which recently mass-mailed "resource packs" to UK secondary schools. Whilst ostensibly encouraging biology teachers to address the 'controversies' in evolutionary theory, these packs offer nothing but a mish-mash of bad and extensively debunked arguments intended to confuse students about the current status of biological science, and suggest a false scientific equivalence between the theory of evolution and more literalist interpretations of the Bible (currently hiding behind the phrase 'Intelligent Design'). The extensive scientific inaccuracies contained in Truth in Science's literature, and the strong creationist links of its principal members, are well documented by the British Centre For Science Education (http://www.bcseweb.org.uk/index.php).

Your colleague Graham Stringer has submitted an early day motion (EDM 2708)which repudiates the approach of this group and advises schools to treat this material with caution. Quite aside from the fact that this group is encouraging the teaching of bad science, muddying the boundaries between science and peoples' different religious views is inherently dangerous, particularly in the current climate (and in the view of the present vogue for faith schools). I hope that you will consider supporting this motion.

Yours sincerely,

I'm somewhat cynical about whether this e-mail just won't be junked by a secretary somewhere, but it's worth a go. I'll keep you posted on whether I get a response, and (more imporatantly) whether I get him to sign up.

What caused the Hawaiian earthquake?

2006-10-16T15:13:00.000Z

Far be it for me to refuse a request. In the comments to my last post:

I can't find an email address for you or a more appropriate place to post a question. I'm looking for someone, anyone, who has any ideas about the cause of Sunday's Hawaiian earthquake. I've posted the question on my blog at ElementList [where there is a very cool photo of a rockfall triggered by the quake]. The quake was very deep (~38 km) and was strike-slip. This seems like an odd place for that kind of quake. Any ideas?

This is an interesting one – I should warn that most of what follows will be speculation (informed speculation, perhaps…). First, lets have a look at the USGS moment tensor solution:

Note that the depth is now being reported as 28 km, which is deeper than a lot of the normal seismicity, but not unusually so. However, the size and the location of this earthquake are both unusual. For comparison, here’s a map of seismicity on the Big Island for the year 2000 (from the Hawaii Volcano Observatory).

As you can see, earthquakes are hardly rare on Hawaii; the emptying and filling of magma chambers, and molten rock moving to the surface, all produce stresses which result in earthquakes. However, they are pretty much all less than magnitude 4, more than 400 times less powerful than today’s 6.6. Also noteworthy is that a lot of the seismicity is concentrated underneath the volcanoes, as you would expect if it is associated with magma movement; in contrast, today’s quake and aftershocks, as shown in the figure below (source) were located off the NW coast of the Big Island.

All of this suggests that this earthquake is not associated with the volcanism. So what is the cause? Two possibilities spring to mind:

The Hawaian islands are 5 km-high piles of basalt that represent a very large load on the oceanic crust and lithosphere beneath them, causing it to bend downwards around the bases of the seamounts. The earthquake could be releasing some of the stress building up as the islands continue to grow.

The problem with this is the focal mechanism, which is almost pure strike-slip (horizontal displacement only); you'd expect at least some vertical (extensional) motion if gravitational collapse was involved (much like these, in fact)*. Which leaves option two:

Although most deformation on the Earth occurs at plate boundaries, some stresses are still transmitted to the interior of plates, where they cause intra-plate earthquakes at weak points. It could be that the crust around Hawaii is such a weak point. My first thought that this was an effect of the hotspot volcanism (lots of cracks for magma migration, etc.). But then another thought occurred. Here’s a bathymetric map of the Northern Pacific:

See those long, linear features? They’re oceanic fracture zones, the inactive parts of the transform faults which separate the spreading centres of mid-ocean ridges (these Pacific ones eventually join the East Pacific Rise just off the west coast of the Americas). And one of these fracture zones, the Molokai Fracture Zone (rather bizarrely abbreviated as OFZ in this particular image) just happens to intersect with the Hawaian Islands. It’s quite common for inter-plate earthquakes to occur on old faults, as they’re much weaker than surrounding rock, and the focal plane solution is consistent with an E-W trending structure.

So that’s my guess: this earthquake is accommodating large-scale, intra-plate strains in the Pacific plate (shifting up into really speculative, I’ll note the nice correlation to the ~NW absolute motion of the Pacific plate - see here for example), and may be due to reactivation of an old fracture zone, or a structure associated with it. More knowledgeable heads are free to weigh in and correct me...

[Update: Western Geologist has a good post up pointing out that there's a big difference between the USGS focal mechanism given above and the Havard CMT solution, the latter indicating an oblique extensional fault - more consistent with the quake being a response to plate loading - rather than strike slip and suggesting that the focal planes may not be well constrained. He's also dug out the locations and mechanisms of other large (non-volcanism related) quakes in the last 20 years, and discusses how they relate to this weeks'.]

Some updates

2006-10-12T14:27:00.001Z

More info on the North Korean nuclear test (or ‘tesr’, as it was in my title for a couple of days): Jake points to CNN report that it was supposed to be a 4 kiloton device - that’s what the Chinese were told by North Korean officials before the test, anyway. If a 10-15 kT device generates a magnitude 5, magnitude 4.2 would represent a yield of 1.6-2.4 kT (very rough calculation – it’s a logarithmic scale, and the starting figure isn’t exactly precise), so it’s a little on the low side, indicating something didn’t go right (it’s not completely impossible that some bizarre combination of large cavity size and local geology led to very inefficient conversion into seismic waves, but that would be mighty convenient). Arms Control Wonk has some speculations on what - plutonium is much more tricky than uranium, it seems. Meanwhile, the Lab Lemming takes the time to debunk the hysteria over a possible second test (quite how a subduction zone earthquake off the Japanese coast got mixed up with a shallow explosion on the Korean Penisula is beyond me - when I first heard this rumour I just looked up the USGS map of recent activity - which clearly just shows Monday's event - and that was that).

Further to my rant about Truth in Science, I was glad to discover that there’s more than a few of us who aren’t going to let their false appeal to ‘balance’ fool anyone. The British Centre For Science Education have a whole section devoted to Truth in Science, and they’ve dug up some interesting facts about the clear creationist roots of the major players in this organisation as well as joining in the debunk-fest. Science, Just Science are also on the case, with a whole topic in their discussion forums. It’s nice to know I’m not the only one worrying about this; although we may not be quite as infected with the creationism meme over here, we don’t have that pesky separation of church and state thing either.

North Korean nuclear test

2006-10-10T16:17:00.000Z

See also my update

Lab Lemming asks whether seismology can say anything useful regarding North Korea’s nuclear test. You’d certainly hope so, as monitoring of the Comprehensive Test Ban treaty relies upon it. An earthquake, where rock slides along a fault plane, generates both compressional (P) and shear (S) waves (but generally more of the latter), and patterns of compressional and dilational first motions in the P waves (which are the basis of the beach ball-like focal mechanisms I’ve discussed previously). Explosions basically just push the rock outwards in all directions, producing lots of P waves, not many S waves and a focal mechanism which looks like a big solid circle.

The USGS has confirmed that they detected a seismic event, magnitude 4.2 , which appears to correspond to the test, but they have yet to generate a focal solution (they don’t usually bother for events smaller than about magnitude 5, probably because the signal received at distant stations is too weak to reliably measure first motions). However, the Western Geologist has dug up some seismograph data from here, which I’m just going to lazily reproduce: the first graph is the North Korea event, the second is a recent earthquake for comparison (each line represents one station, which are different distances away, hence the time difference).

P waves are faster than S-waves, so will be the first to reach the station. It seems that for the North Korea event, a lot of the seismic energy received is in the first 10-15 seconds, and the signal dies out quite quickly after that. In contrast, the signal for the Japanese earthquake is received for more than 2 minutes, and the first peak is much less pronounced, suggesting that more energy is arriving in the form of slower S waves, and significant (above background) vibrations are received for a much longer period.

So, it seems likely that this is indeed an explosion, although that says nothing about whether the device actually worked; that would depend on knowing what the intended yield was, and even then it’s tricky, because not all of the energy released will be converted to seismic waves. This uncertainty may be behind the large discrepencies between the various estimates of the size of the explosion reported by New Scientist (see also the discussion at No Se Nada), which has led to speculation that the bomb might have ‘fizzled’. For what it’s worth, one of the textbooks on my desk says that a Hiroshima-size device (10-15 kT TNT equivalent) should generate a magnitude 5 quake, so if it didn’t fizzle, it seems to have been quite a small nuke.

UK successfully clones Discovery Institute

2006-10-09T14:14:00.000Z

See also my update

I had this weekend all planned out: chill out for a bit, play around with next week’s lectures, maybe even finally sort out how to migrate everything over to Blogger Beta without destroying my layout. Unfortunately, the letters page of Saturday’s Times has sent me off on a slightly depressing tangent. Three letters were part of a continuing discussion about a story in the Times Education Supplement a week or two ago, about the recent activities of a group called Truth In Science.

Every secondary school in the UK has been targeted in a new campaign promoting the teaching of creationism in science lessons. Heads of science at 5,000 schools have been sent teaching materials casting doubt on Darwin’s theory of evolution and encouraging children to consider alternative interpretations of life on earth. A booklet and two DVDs, created by Truth In Science, an influential group of academics and clergymen advocating more “balance” in GCSE and A-level science, were mailed to private and state schools this week.

The discussion has led one of the members of the ‘scientific panel’ of Truth in Science to write in:

Truth in Science is seeking to enable school science students to follow the evidence for and against evolution wherever it leads.

We are committed to truthfulness and good science, and invite our critics to identify the alleged “scientific errors” of our website. Where convinced they occur, we will correct them.

Okay then.

I’ll ignore the fact that members of a group calling itself ‘Truth In Science’ have rather obviously failed to grasp the rather fundamental point that science is not engaged in a search for Truth, but models which have predictive and explanatory power. I’ll also pass over the fact that the first thing on their website (I’m not linking to it, but it's truthinscience.org.uk if you’re interested) is exactly the sort of weasel-like interpretation of a statement in the National Curriculum I feared when I first saw it (sometimes I hate it when I’m right). I’ll even be charitable and give them a pass on the fact that, for all their talk of misrepresentation of alternatives to evolutionary theory, there’s nary a mention of what they might be in their non-misrepresented form. Let’s instead examine a few items on the laundry-list rather bizarrely entitled ‘Evidence for Evolution’, which I suppose is trying to imply that it represents the best modern science has got.

Antibiotic resistance:

Most types of antibiotic resistance were already in existence before antibiotics were discovered and used extensively to treat infectious diseases.

‘Most’ is pure weasel, hedging bets against the obvious rebuttals that antibiotic resistance does evolve. Of course, that’s only “microevolution” because “they’re still bacteria”. Clearly these guys haven’t seen that when it comes to diversity, bacteria beat us hands down – it’s just all at the biochemical level.
Comparative Genetics and Biochemistry

There is, of course, much dissimilarity between living organisms, some of these at a very fundamental level. For example, the standard system of genetic code used by humans is not universal. Eighteen different genetic codes have been found in various species. Many scientists see this as evidence that all life does not come from a single common ancestor.

Name some, please (biochemists, preferably). It’s true that some variations in the standard genetic code have been discovered, only a few of the 64 codons are different in any of these variants. Look, for example, at the mitochondrial genetic code; and here’s a full list of known variations and their taxonomic ranges. Note that most are found in bacteria and other single celled-organisms, which are merely microevolving so don’t count anyway. Yes, that was sarcasm.
The Fossil Record

The key problem is this: Darwin’s theory relies on minute changes in organisms which slowly accumulate, gradually changing the organism until it eventually becomes a new species. If this is correct, then the fossil record should contain many fossils with forms intermediate between different species. This is not what the fossil record shows.

One word: Tiktaalik (see also here. Or how about when whales went back the other way? Or the increasing cranial capacity of hominids?.

About half of the major animal groups appear, fully formed, in the Cambrian strata of rocks, with out any fossilised ancestors.

Wrong, unless you think tens of millions of years is ‘sudden’. And, at the time, all the major animal groups were ‘variations on a theme of worm’, anyway. There were no mammals, reptiles, birds, even insects, as we know them.

Well that wasn’t hard, and I could go on, but when I saw them harping on about Peppered Moths and Haeckel’s embryos, it became clear that this is just Jonathan Wells’ Icons of Evolution, redux, and that has been pretty finely shredded by people far more qualified than me - as has it’s new, unimproved incarnation.

Besides, I don’t want to rot my brain too much. I’m meant to be teaching actual science tomorrow.

Worship the awesome geo-nerd!

2006-10-06T09:02:00.000Z

So says Kevin Vranes over at No Se Nada (OK, so I paraphrase a little...). Anyway, welcome to those who have got here from there - the highlights of my last year's ramblings are handily summarised here.

If you haven't, go and read his account of an interesting new paper by Latif et al., which tries to estimate the amount of multidecadal variability in the meridional overturning circulation (MOC). This is poorly known, which makes interpreting the results of Bryden et al.'s Nature paper rather difficult (Kevin's just reposted his take on this, which is similar to mine).

Their estimate is indirect: they've taken the fact that in climate models changes in the MOC are expressed as specific changes in sea surface temperature (SST) patterns, looked for this signal in actual SST records, and used that to estimate that the strength of the MOC might vary by 1.5–3 Sv (10⁶ m³/s) over multi-decadal timescales. For reference, the reduction estimated by Bryden et al. was about 8 +/- 6 Sv.

What I'm still waiting for is the results from the moorings Harry Bryden deployed in 2004, which have been recording real-time data on the short-term (annual, monthly, daily?) variability of the MOC. As I commented over at No Se Nada, I've heard rumours that they've found some and it's significant; I'll revisit the issue when this paper is published (thanks to Steve Bloom for knowing his way around the NOC webpages better than me).

Mountain musings 2: What’s God got to do with it?

2006-10-05T20:23:00.000Z

“Don’t these mountains make you think of God?”

I was asked this question by one of my walking companions as we lunched in front of a particularly awe-inspiring Alpine vista, on my recent excursion in the Vanoise National Park.

I paused, considering the most appropriate way to respond, before deciding that honesty was the best policy.

“Not really, no.”

My inquisitive companion is a good friend of mine from University, and an evangelical Christian. He was also, by way of a somewhat heated discussion on the virtues of radiometric dating on an earlier walking holiday, one of the people who first made me aware of the widespread sympathy for literalist biblical creationism amongst even moderate-seeming evangelicals. Fortunately, this conversation petered out good-naturedly (I don’t always pick fights for the sake of it), but it bothered me, I think because in some ways it encapsulates the tension between science and (some) religion.

As I was looking at those mountains, I was thinking of how millions of years ago, the limestone I was sitting on was slowly being formed in a shallow, long-vanished sea, before the ongoing collision between Africa and Europe forced it a mile up into the air, scrunching the beds up into crazy folds. I was taking in the myriad signs that the glaciers currently confined to the very highest peaks once carved out all the valleys we were looking upon, evidence of the waxing and waning of Quaternary glaciation. I was considering how, over millions of years, all of those peaks and cliffs would be ground back down to sea-level, just by the action of ice and water.

Purple prose aside, all this has a tendency to overwhelm thoughts like, “What pretty mountains God has made for me!” For a start, I know enough to be aware of the overbearing hubris in the notion that The Alps were put there for my benefit. They were here before our great-times-10 000-grandparents had sorted out bipedalism; they will still be here uncounted generations after we, and possibly our entire species, are dead. Yet despite that vast lifespan, the entire cycle of the birth and death of a mountain range represents only a tiny fraction of the history of our planet. That’s enough to prick anyone’s pretensions of grand cosmic importance, even without considering our decidedly non-privileged status in the Universe at large.

And herein lies the problem for many people. They don’t like to feel small and insignificant, and they certainly don’t like the theological implications of being such a tiny part of a universe so mind-bogglingly old and large and alien: namely, that if there is a God that set the whole thing in motion, it is just as mind-bogglingly vast and alien – and it may not consider us to be particularly important. For many people of faith, and evangelical Christians especially, the idea of a personal relationship with God is central to their lives; how can they feel close to such a distant and incomprehensible being?

(The ironic paradox, of course, is that this is exactly the fall-back excuse for the whole theodicy problem – bad things happen to good people because ‘God moves in mysterious ways’).

I wonder if this tension is the root cause of many of the characteristics of the modern evangelical: the suspicion or even outright denial of science, particularly evolution and geology; the biblical literalism (God is hardly detached and aloof in the Old Testament, is he?); and the readiness to see the presence of God in every innocent mountain (whilst pitying people like me, who don't).

Fortunately, the mountain doesn't care. It just is.

My academic life

2006-10-04T09:31:00.000Z

Jorge Cham nails it as always, but this one has a particular resonance for me right now.

Of course, unlike Mike, I might actually leave someday.

One year on

2006-10-01T18:16:00.000Z

A small problem with my new flat's electrics prevented me from exactly marking the anniversary of the post that started my little blog. After a shaky start, I have been much better in recent months at producing posts semi-regularly - at least, when I haven't been gallivanting off to some internet-deprived corner of Europe.

As befits my blog’s name, I’ve drifted a bit about through the many different disciplines which fall under the aegis of Earth Sciences. My interest in planetary geology has led to discussions of possible subsurface water on Mars, the past geological history of Titan, and, during the Pluto controversy this summer, how Ceres might be a worthy planet after all (sadly the IAU didn’t agree).

Back on Planet Earth, I’ve looked at the uncertainties behind the doom and gloom headlines about the collapse of the thermohaline circulation, and how even if it happened it wouldn’t be the Day After Tomorrow. I’ve also fixated a bit on the poor understanding of the science, and particularly the limits of earthquake and volcano prediction, one of the items in my list of annoying misconceptions in Geology leading to posts on a rather odd proposed earthquake precursor, the blend of luck and expertise whichled to an apparently accurate earthquake alert in China, and seasonal variations in the frequency of volcanic eruptions. And, in the run up to the UK government releasing a new, improved energy review, I took a skeptical look at their new-found enthusiasm for nuclear power, one of the valid objections to which isn’t that we’re running out of uranium.

Another thing I have noticed is that other than a short introduction to my own subdiscipline, paleomagnetism, I haven’t really talked about my own research, which is definitely something I want to rectify in a few months.

Whilst waiting around in Southampton to defend my PhD thesis, I’ve also been employed as lab-skivvy and teaching cover for my supervisor. It’s not always been easy, especially when I’ve been marking some rather poor exams, but it’s given me some important insights into the art of teaching science. And despite the odd moan, my position has had its compensations - a field trip or two, for example.

And, like most scientists nowadays, I’ve fretted over the rise of irrational thinking, particularly in the form of ‘Intelligent Design’, creationism with added nudges and winks. It seems the UK is not immune; but despite the warning signs, it appears that things are not as bad as they are across the Atlantic.

Of course, the fact I've been writing stuff says nothing about whether it's worth reading. That judgement, of course, is out of my hands.

Mountain musings 1: The hard climb of science

2006-09-27T23:15:00.000Z

I’ve just spent a week hiking in the Vanoise National Park; we did a five day loop around the main glacial massif. On the whole, it was a thoroughly enjoyable experience; after an unpromising start the weather was fabulous, the scenery fantastic (I took an old film camera so no photos to show off as yet) and I had the unforgettable experience of a golden eagle flying 10 feet above my head, close enough to pick out individual feathers on his underbelly. I’m glad I didn’t look like lunch, although his long stare indicated he was thinking about it.

The hike was no without it’s challenges, however, and the second day was particularly hard work. On paper, it was difficult enough; 1200 m of ascent, including a stiff climb to 2916 m to get across the Col d’Aussois. In reality, we proceeded to make it even tougher for ourselves by getting un peu perdu. As we approached the Col, we lost the trail, but we could see a track going up the hillside across the river and decided that must be the route. We persevered with this belief even after we discovered that the bridge promised in our guidebook had apparently vanished; it was only when we’d spent an hour struggling up it - and reached a much lower col on the wrong side of some rather hefty mountains – that we realised that we’d gone a bit wrong. When we looked back into the valley, we could see the actual track, heading upwards into the next valley. Merde.

Fortunately, our elevated perspective also showed us that we didn’t have to completely retrace our steps, an option almost as unpalatable as heading on and trying to find another route across the ridge; instead, we just had to descend enough to contour around into the next valley, and then re-ascend to rejoin the trail up to the Col d’Aussois after it crossed the river (on a very existent bridge). Despite this short cut we lost almost two hours, and fretting over time combined with tiredness from our abortive first ascent, the altitude, and an unrelentingly steep path to make the ascent to the top of the proper col one of the toughest things I’ve done in quite a while. My world contracted in on itself; the track was reasonably well marked by cairns, and rather than focussing on the distance to the summit, my mind was fixated on driving myself onward to the next cairn, and then the next one, and then the next one… all the time my breath was getting shorter, my rucksack was getting apparently heavier, and lifting my feet was becoming ever more difficult. And then, just when I thought I’d reached the top, I struggled over the break in slope to discover yet more up. By this stage, it’s only slightly melodramatic to claim that the point of the ascent was only a dim recollection in the back of my mind; pretty much the only thought in my head was, “I’m not going to let this bloody hill beat me!”

By 7.30, we’d all got to the top. Unfortunately, that was not the end; we now had to descend down to the refuge on the other side of the col. Down was good (although gravity can be a fickle friend when you’re knackered), but we had the small problem of about 90 minutes’ walking and half an hour of daylight left to do it in. Fortunately, thanks to one of my companion’s inspired twilight route-finding, we only needed our torches for the last 20 minutes, but even so we almost overshot our destination.

In the end, what should have been an eight hour trek had taken almost 12. However, although negotiating mountain trails in the dark is hardly recommended, we were never really in serious trouble; as a tale of danger and fortitude, this is hardly Touching the Void territory. However, looking back as the hike continued, I found myself thinking back to a post I started writing a few weeks back, discussing the vast gulf between the public perception of science and the process of actually doing science*, and I couldn’t help drawing parallels between that the physical ordeal of that day and the mental struggle of a PhD, or any research project. You start at the bottom of a big hill, and despite previous research as a guide the way forward is not clear (especially if you don’t find the key publication, as we neglected to properly consult the map). When a route does present itself, it may not be the correct one, and it may take you considerable time and effort to discover this. Your wrong paths may not be a complete dead end; a negative result can still constrain the problem, or (as happened during my PhD), the result which undermines a key assumption may finally reveal the true path to understanding. It’s disturbingly easy to get so lost in the day-to-day grind of generating and processing data, that you almost lose sight of the reasons you were interested in the first place. Just when you think you’ve got there, you discover a new complication with your data. And, of course, it takes much longer than it was supposed to.

If I really wanted to get lost in the metaphor, I could run with the whole “standing on the shoulders of giants” angle by musing that the hard day’s climbing gave us access to some spectacular mountain scenery in the following days. That, however, is somewhat immaterial to my point. I’ve often thought that a shortcoming of most science reporting, centred as it is around (if we’re lucky, informed) regurgitation of Nature press releases, is that it is exclusively concerned with the outcomes: the exciting results and nifty new hypotheses. Results are important, of course, but I sometimes think that focussing only on the final part of the scientific process means that many people do not realise exactly how many years’ graft has gone into attracting the public attention for that fleeting second (if it ever does). A scientist’s week does not consist of thinking up a nifty idea on Monday, running down to the lab and testing it on Tuesday and Wednesday, writing it up on Thursday and getting the plaudits on Friday. The view is great from the top - but it takes a whole lot of climbing to get there.

*Yes, I was thinking about blogging. But a nice walk has always provided good thinking time for me, so it’s not quite as sad as it might appear. Honest.

Gone roamin'

2006-09-16T06:39:00.000Z

It's been a busy few days, as I've been trying to get stuff finished before I head off to do some walking in the French Alps. Lets hope the weather smiles on me.

Those needing their fix of top-notch writing can do worse than head over to the first edition of Philosophia Naturalis, the long-awaited physical sciences carnival now up over at Science and Reason. Tell them I sent you.

The curse of the nerd

2006-09-13T22:43:00.000Z

There’s a lot of posturing at the moment over at Scienceblogs (follow the links here, for example) over who is the nerdiest of them all. In some ways, this is an encouraging affirmation of the universal characteristics of human nature. Change a few key terms, ‘slide rule’ to ‘alloys’, for example and you could be in the streets of Essex listening to teenagers showing off their latest set of wheels. We just can’t resist the urge to shout about what hot stuff we are, even if the requirements within different social groups are somewhat different.

Over at Cosmic Variance, where Sean has an interesting take on the whole exercise:

I’m all in favor of celebrating nerdliness. But for me it’s very much a part of what should be a general appreciation for intellectual endeavor, whether technically oriented or not. And as a matter of personal experience, I’ve found science and engineering types to be at least as anti-intellectual as the average person on the street, when it comes to non-technical kinds of scholarship.

What is worse, there’s a certain point of view… that actually celebrates social awkwardness for its own sake... And that’s just wrong. I’m not talking about principled eccentricity, letting your freak flag fly — nothing wrong with that, in fact it’s admirable in its own way. Nor am I saying that everyone should be scouring the latest issues of GQ and Vogue for fashion tips; superficiality is just as bad as nerdliness. And laughing at our high-school (and college) selves is always fun and healthy. All I’m saying is that there is much to be valued in an ability to relate to other kinds of people in a disparate set of circumstances, take care of your appearance, and function effectively in a wider social context. These are skills we should try to cultivate, not disparage.

How true. One of the more unpleasant aspects of working in academia is that bullying, petulance and general obnoxiousness is an accepted (or, at best, tolerated) way of progressing in your field. In my department, I find myself in the odd and entirely undeserved position of being at the high end of the social skills spectrum, which even my best friends in the real world would tell you is a little frightening.

But why is this? I think this actually does link back to the somewhat negative stereotypes at large in general society: scientists as bumbling, socially inept and desperately uncool loners; science students as all of the above with added spots, crooked teeth and thick glasses. This is not an image your average teenager, highly susceptible to the ebb and flow of peer approval, wants associated with them, thanks very much. Hence even if there is a genuine interest, many do not persist in science (or, more accurately, put in enough work to leave the option open). Those who do are either comfortable enough with themselves to follow their interests despite peer pressure, or lack the social awareness to perceive or care about it*. I would submit that the latter group is by far the larger.

So it’s all a bit circular really – through this process of self-selection, those on the path towards a scientific or technical career are on average more socially inept than the general population. Within the group poor social skills are the norm, so they persist, reinforcing the general cultural stereotype and keeping scientists 'uncool'. Additionally, within the group there is also a backlash against other parts of culture, seemingly the preserve of people who look down on the science geek; hence the apparently contradictory anti-intellectualism that Sean notes. Breaking that circle is not an easy thing.

*Or you're such a well-known swot that you can choose to do what you like, in the certain knowledge that nothing you do will change people's perceptions of you.

Waking up

2006-09-11T23:45:00.000Z

I must have been one of the last people to fly in that innocent age when thoughts of disaster tended more towards mechanical failure than being used as a missile. Early on the morning (UK time) of 11th September 2001, my long-haul flight from Singapore was flying in over the centre of London to land at Heathrow. I had just spent the summer travelling around the world as a post-graduation present to myself. I arrived back home in the early afternoon, and switched on the TV. I can't swear that my memories have not been melodramatised over time, but this was at about the time that the second plane hit the World Trade Centre. The next few hours seem unreal even now, with my jet-lagged brain recoiling from the sheer nightmarish horror of what unfolded.

Cut to five years later, and in a very real sense the dust from that day has yet to settle. Like many others, I'm not sure I'm liking the shapes of the new world which are starting to poke through the haze, partly a result of our leaders' delusion that you can declare war on, and beat, a noun (and an illegitimate proper noun to boot - I know what 'terror' is, but 'Terror'?). But given that more than enough is being written about the (mis)deeds of Bush and Blair, I find myself instead wanting to consider a slightly different notion: the idea of 9/11 as a 'wake-up call'. I am wondering, what exactly should it have woken us up to?

The obvious answer is the one our leaders give, and our media amplify: that there are scary people out there who want nothing less than the destruction of our entire way of life, and are willing to murder thousands of innocents to achieve it. This is true, but amoral sociopaths existed before five years ago. A more chilling realisation is the fact that in certain parts of the world, these peoples enjoy an alarming degree of support in the general populace, to the extent that the attacks on New York and the Pentagon were, and are, celebrated as the acts of heroic martyrs. That is dwelt upon, but perhaps less than it should, because it is a step on the slippery slope to thinking about the causes of that hatred.

I should probably add at this point that I utterly deplore any act which deliberately leads to the loss of innocent life - to discuss the causes of something is not to condone it. However, the necessity of that disclaimer is telling; it says that we are uncomfortable with questioning our unpopularity in the Middle East, and elsewhere. We would prefer to think of it as unreasoning and baseless. We're the good guys, surely? Our societies are free and tolerant and peaceful. No one could have any rational reason to hate us.

Unfortunately, our ignorance does not mean that such reasons do not exist. The advantages of liberal democracy, our freedom to live our lives the way we see fit, relatively free from disease and poverty, do not come without costs. The problem is that in our increasingly connected world, we are increasingly able to export those costs to the fringes. We have laws regulating working hours and the minimum wage, but we buy cheap clothes and trainers from countries that do not. Our supermarkets stock affordable fruit and vegetables imported from all corners of the earth, but those that grow it are not always given a fair price. Much of our meddling in the Middle East is linked to our need to secure cheap energy.

It is easy to ignore what we are not forced to see. We are vaguely aware of these issues, but being insulated from them we see the postive aspects of our society much more clearly. To those on the outside, however, where the negatives can impinge much more directly on peoples' daily lives, it is no suprise that their views are somewhat more ambivalent. If they feel that they are suffering to support our priviliged lifestyles, and if our immigration controls and trade protectionism appear to be preventing them from joining the party, then it is only a small step to the conviction that it is all intentional, that we are out to destroy them. And you can always find people - fanatics, power-hungry manipulators, weak despots - willing to help others make that step. Perhaps what we should have woken up to five years ago is that we have helped, however inadvertantly to make it a disturbingly small step for a disturbingly large number of people. Instead, by buying wholeheartedly into the 'Us versus Them' framing of Al-Quada, we have if anything made that step even smaller.

Lego Weapons of Mass Destruction

2006-09-04T16:27:00.000Z

Remind yourself of the awesomeness of LEGO. Coincidentally, I'm moving flat at the moment and the junk under my bed includes a shoebox-full of the stuff. The urge to play is strong...

Via Kevin Beck.

The long road to ozone hole recovery

2006-09-01T14:50:00.000Z

I'm somewhat late commenting on the story that the Antarctic ozone hole appears to have stopped growing, but I put together this figure last week by pulling images off the NASA Ozone Hole Watch website (click here for the latest image from this year), and it seems a shame to waste it. It depicts how the springtime concentration of ozone over the south pole has varied since 1979. Blue and purple indicate low ozone concentrations, green and yellow high concentrations.

This figure provides a qualitative impression - that the area of ozone depletion in the 2005 season was not enormously bigger or deeper than in 1999, and in fact appeared to recover a little earlier. This impression is confirmed by the more rigorous (but less pretty) figure below, which shows the annual variation in the size of the ozone hole since 1979 - click on it for the original (and clearer) version at this NASA site, where you can also see how the severity of ozone depletion has varied.

So it seems that in fact things have been stabilising for a while now - the sudden media interest can be traced to a NOAA press release to mark the 20 year anniversary of the study that confirmed that chlorine, released when CFCs are broken down by ultraviolet radiation, was the cause of ozone depletion above Antarctica. This work combined with a rare outbreak of non-partisan international cooperation to produce the Montreal Protocol. Even more remarkably, the agreement was actually pretty effective at curtailing the production of CFCs and other ozone-damaging chemicals:

(source)

However, the important thing to notice is that the thinning of the ozone layer above Antartica continued throughout the 1990s; although we cut the production of ozone-destroying chemicals, the molecules of those we have already released are persistant beasties, surviving in the atmosphere for anything up to 100 years. Indeed, as the graph here shows, the atmospheric concentration of flourocarbons has merely stablised in the last decade. Until it begins to fall, springtime ozone depletion above the Antarctic will continue (the latest research estimates full recovery in about 2065). The fact that our atmosphere is still suffering the consequences of CFC emitted two decades ago is a warning about the consequences of the other changes we have wrought on atmospheric chemisty. Even if we can agree to seriously cut the emission of greenhouse gases in the next decade or two, the full effect of what we've already emitted, and are currently emitting, will not play out for a long time afterwards (especially since climate change affects the ocean, which responds over timescales of centuries, not decades). More people need to realise that emissions cuts will not put the brakes on climate change; it is more akin to taking your foot off the accelerator.

Two degrees of under-valuation

2006-08-30T16:18:00.000Z

This week has not been a good one for a postdoc working in my lab, who has now managed to break two pieces of our equipment on consecutive days. This guy is from the 'be absurdly deferential to your superiors, trample on the dignity of your inferiors' school of academia, so both times I have been treated to barely civil demands to drop whatever it is I'm doing and get on with fixing them for him. No apologies were offered for his clumsiness, of course, which have sadly (for him) caused damage beyond my ability to repair.

I'm bristling somewhat at his brusqueness, but part of the problem is my stupid employment situation; when you're employed as a technician (even one who just happens to spend much of his time lecturing, marking, and teaching on field trips) it should hardly come as a surprise when I'm treated like one (not that such treatment is justified in any circumstances, but this person certainly wouldn't have treated me in that way if I was academic staff). However, this sort of thing actually happens so rarely that I was more than a little annoyed. I'm lucky in that most people around here react to what I do rather than my job title. They generally think that I should make more of a fuss about my current situation, but unfortunately until I get some leverage (a good job offer from somewhere else, for example) the Powers That Be merely brush off my complaints.

On a slightly more surreal note, my confused status in the building is further complicated by the fact that the computer system still thinks I'm a PhD student. This has suddenly become more than a mild annoyance (mainly because I get all the bureau-spam for the post-grads in addition to the technical and academic stuff) with the rebuilding of the departmental webpages. We're all getting a personal page, and on the draft version I'm currently listed under PhD students rather than staff. What's amusing is that my title is 'Dr.' Clearly I'm a glutton for punishment.

Pluto, king of the dwarfs

2006-08-24T20:13:00.000Z

Did the IAU actually do anything useful at their General Assembly? I sincerely hope they didn’t waste the whole of their time in Prague arguing about Pluto – that would be a tragic waste with so much fine beer to be sampled.

Anyway, as Nature’s woman in the trenches reports, after a few days of wrangling and counterarguments to the original proposal, the whole thing came down to a few rounds of waving yellow cards in the air. Roundness is still a criterion, but to make it into the big league you also have to have cleared your orbit of other major bodies – if you haven’t then you’re merely a 'dwarf planet'. See the bottom of this press release for the full text of the resolutions. Phil has more at Bad Astronomy, and thinks it’s still a bit arbitrary. Josh is happy. My opinion remains unchanged.

The difference between cynicism and skepticism

2006-08-23T21:48:00.000Z

I watched an interesting, if disturbing, documentary on BBC2 last night, about the case of an alleged child abuse ring in the Orkney Isles. This case highlights the problems that arise when people refuse to question their assumptions, but also illuminates a key difference between the often confused concepts of cynicism and skepticism.

The facts are provided by an accompanying article for the program on the BBC website:

In 1991, five boys and four girls, aged between eight and 15, were taken from their homes on South Ronaldsay.

The children, who could not be identified at the time, returned to their homes two months later when legal action was thrown out by a sheriff…

…The raid was organised after social workers questioned members of another family - the W family - whose father had been jailed for sexual abuse.

They became fearful there was a child sex ring and ritual abuse taking place on South Ronaldsay.

The documentary interviewed some of the children, their parents, and other Orkney locals who were involved in a public campaign for the return of the children, as well as some of the people working for the social services at the time. The behaviour of this latter group during the incident was, to say the least, somewhat questionable. Dramatised transcripts of the interviews they had with the children showed that they placed intense pressure on them, pushing the subjects to ‘remember’ abuse even in the face of strong denials that anything had happened.

The whole thing was a giant trap of self reinforcing credulity. A real case of abuse – the father of the W family – was suspected of being only the tip of the iceburg, thanks to the belief (freshly imported from America) that a large proportion of childrens’ behavioural problems had their roots in unreported physical and sexual abuse. The social workers believed that more people were involved. If the children denied it, they were just repressing the horrible memories, and needed to be pushed to remember them. If the parents denied it, well of course that’s what they’d say! At no stage was the possibility that there was, actually, nothing to uncover even briefly entertained. Even now, after the allegations were dismissed and they were strongly criticised for their handling of the case, the social workers are struggling to accept that they got it wrong. Some are even struggling to get that far: one is as fervent in her beliefs now as she ever was, saying:

"But people saying things didn't happen doesn't affect me in the slightest.

"Because that's my experience of what people always say. I'd be very surprised if they said it did."

One thing that struck me about this case was that the social workers appeared to have a very dim view of human nature, perfectly prepared to believe that large numbers of people were involved in the abuse of children. This is interesting, because a common accusation levelled at skeptics who question the effectiveness of homeopathic remedies, astrology, psychics and other woo is that we only reject these ideas because we have such a negative and suspicious worldview. ‘It’s easy for you to pick holes,’ they say, ‘why can’t you open your mind and give it a chance?’

In Orkney social services, however, we had an environment where there were suspicions of widespread abuse, and the lack of skeptical thinking meant that the optimistic scenario – that there was none – was not given air. This highlights an important point: skepticism is not negative thinking, it’s critical thinking - the rigorous examination of all ideas, particularly ideas you are predisposed to believe. Whether these ideas are positive (‘Some people can read minds’) or negative (‘most parents abuse their children’), the important question for the skeptic is always: based on the evidence, am I justified in believing that?

In fact, I’d argue that skeptical thinking is as much a guard against kneejerk cynicism as it is against unreasoning credulity. Look at my reaction to the recent terrorist arrests. My cynicism leads me to suspect some political theatre, but fortunately my skepticism prevents me from treading too far down the road of the conspiracy theorists; people who are so convinced of the murky agendas of the US that they’re prepared to believe they fabricated the whole thing (see some of the comments here, for example). Caught in a pincer movement between the cynics and the credulous, villified by both, the skeptic can only hope that one day, everyone will have read The Demon Haunted World, and joined us in the reality-based community.

Ceres – not just a ball of rock

2006-08-21T15:33:00.000Z

Lab Lemming, who commented on my post about Pluto, has his own thoughts on the issue. I liked his conclusion:

If a second-grader asks if they are really planets, instead of boring him with committee recommendations and pedantic debate points, we give him a scientific answer: “We don’t know yet; we need to send a spacecraft there in order to find out.” Our planetary system deserves nothing less.

Hear, hear. Also interesting was his mention of recent research which suggested that Ceres is in fact differentiated, and therefore possibly worthy of planetary status (another interesting fact: Ceres comprises 25 percent of the asteroid belt's total mass). Hubble observations published in Nature last year [doi] by Thomas et al. indicate that Ceres is a flattened spheroid. As we all know by now, Ceres is large enough to be compressed into a spherical shape by its own gravity; however, its rotation will result in an equatorial bulge, meaning that the diameter measured across the equator is larger than the diameter measured from pole to pole. Thomas et al. measured the difference as about 32 km; however, if Ceres was a homogeneous body, we’d expect a body with its average density to have a difference closer to 40 km (just for reference, the average diameter is about 950 km). This discrepancy can be explained if Ceres is not homogeneous, but is instead differentiated with high density material (rock) concentrated at the core and lower density material (ice) on the surface. Depending on what density is assumed for the core material, modelling indicates that an icy ‘mantle’ of the order of 100 km thick would fit the observations.

These results were a rapid confirmation of a hypothesis published earlier last year by Thomas McCord and Christophe Sotin in Geophysical Research Letters [doi]. They tried to model the thermal evolution of Ceres since it formed (similar to the modelling done for Titan I’ve talked about in the past) and found that given its size and likely composition, internal heating due to radioactive decay was overwhelmingly likely to cause differentiation. They also commented that the best estimates of flattening at the time (which Thomas et al. refined but did not radically revise – it seems a little unfair that a later and less comprehensive paper probably got more publicity just because it was published in Nature) were consistent with a differentiated internal structure. They even remembered to throw in the obligatory reaction to the presence of liquid water (in the past, at least):

This suggests that chemical reactions could have existed and formed molecules of interest to exobiology studies.

More background is available here. Ceres is potentially quite interesting, people – good thing NASA decided to undo their decision to cancel the probe they’d already largely paid for; Dawn is off to visit it next year, arriving at Ceres in 2015.

Of planets and plutons

2006-08-18T10:15:00.000Z

The furore over the status of Pluto – planet, “pluton”, or whatever they’ve decided to refer to it as now - is really missing the point. I can’t believe that the International Astronomical Union is wasting it’s time discussing the exact descriptive boundaries of a noun which has always been scientifically useless.

Ok, that’s a little extreme – back when ancient astronomers were restricted to observing the heavens with the naked eye, it made sense to subdivide all the points of light into those which appeared fixed relative to each other (the stars) and those which moved about (the planets). The planets move (we know now) because they’re part of our solar system, so are much closer to us than the stars are. Therefore, if we’re going by the original sense of the word, any visible body which orbits the Sun is a planet. If the Greeks had been able to observe Pluto, they would unquestionably have said that it was a planet.

We now know a lot more about those little points in the sky – enough to know that they are not at all alike. Any category that encompasses everything from little balls of silicate to gas giants is not really telling you a hell of a lot about its members beyond very broad generalities - it’s kind of like saying you can say something meaningful about life on Earth by referring to everything as a “self-replicating life-form’. For example, one thing all of these bodies do have in common is that they all coalesced out of the same gas cloud. So did Pluto, but then so did and all the other Kuiper Belt objects, and all the asteroids... forming a continuum of objects all the way from dust particles to (as our current census of extra-solar planets illustrates) virtual stars.

Let’s face it, this argument is purely aesthetic and, to a certain extent, nostalgic. People want to give the ‘classical planets’ some sort of elevated status, and are performing all sorts of descriptive gymnastics so we can include Pluto (whose discovery, thanks to one committed astronomer, was probably a few decades before its time). As a scientist, I don’t care whether it’s a planet or not, I want to know things like:

What’s its composition? Silicates? Ice? Gases?
Is it differentiated? Beyond a certain size, internal heating is enough to cause melting, causing heavier elements to separate out and migrate to the core, as iron has in our own planet. If you want to have a lower size limit, this would be my personal candidate; anything which has a clearly delineated crust, mantle and core is in. Perhaps that’s a little too difficult to definitively establish though.
Does it have an atmosphere? What’s it made of? Is it just a leftover or actively maintained?
Is it geologically active (well, it had to get in there somewhere didn’t it)?

Those are some of the interesting questions. Note that “is it large enough for its gravity to squash it into a sphere?” is not among them. Channelling my inner Trekkie, I think that eventually we’re going to have to come up with a slightly more useful classification system (not that this is in any way ideal, but conceptually it’s a good notion), especially as we discover more extrasolar planets. In that context, I suppose the proposal to classify transNeptunian objects with irregular orbits as ‘plutons’ is a vague stumble in the right direction, although I’m not a great fan of them appropriating a perfectly good geological word (pluton being the name for a large, subsurface volcanic intrusion) for their new planetary subclass.

Most commentators seem to agree with me over the silliness of the debate and are also less than impressed by the new classifications. Or both. In the long run, though, whatever Pluto is defined as, I’m still going to be waiting eagerly for the data from New Horizons, which will tell us more about what it’s like.

Evolution still OK in the UK

2006-08-11T22:45:00.000Z

People over the pond (see here, here or here) are somewhat distressed by this graph:

It’s from an article in this week’s Science [doi], and combines the results of surveys in the US, 32 EU or soon to be EU countries, and Japan (the latter was in 2001, the others all last year). The participants were asked a straight yes/no/don’t know question about the validity of evolutionary theory. The USA were edged out by Turkey for bottom spot, showing that the Abrahamic faiths can at least agree on one issue.

However, there is good news for us Brits: we might not be as scientifically ignorant as the BBC poll I blogged about earlier in the year suggested. Whereas that poll suggested that only 48% of the population were convinced evolution happened, in this study it’s more like 70-75%. At the time, I hypothesised that the supposed 17% who supported Intelligent Design may have mixed it up with “some sort of ‘guided evolution/God probably had something to do with it somewhere’-type theism”. If this was the case, the two groups would combine in a a less ambiguous poll like this to give us our 70%. A slightly more nuanced 2003 survey in the supplementary material, where more than half of the 69% who err on the side of Darwin only think evolution is ‘probably true’, supports this interpretation. Likewise, only of the 15% who are creationist-leaning only 8% are True Believers. Typical Brit fence- sitting there

So, should I feel smug first, or relieved?

Lots of heat, but as yet little light

2006-08-11T12:45:00.000Z

One of the frustrating things about the media nowadays their tendency, when trying to cover a breaking story in the absence of much concrete information to convey, of filling the ether with uninformed and unsubstantiated speculation, discussion and analysis – so much so that the hard facts of the case are lost in the noise.

So it has been with the current terror alert in Britain. All we really know for sure is that the police have arrested 24 people who they suspected were about to commit acts of mass terrorism; The Times claim that they included “a biochemist [and] a Heathrow airport security worker", but no-one else seems to have picked up on this. Beyond the fact that the plan involved getting explosives onto commercial airliners, most of the rampant gossip about numbers, timing and ‘liquid explosives’ is unlikely to come from reliable sources (the security services are no doubt rightly saying as little as possible about what they know until they’re sure they’ve got all of the people involved). The Independent has a good summary of what led the security services to suspect these people, and caused them to act yesterday morning.

Only a nutcase would conclude that because our leaders are worryingly prone to taking political advantage of these situations – John Reid can be strongly suspected of exploiting his foreknowledge of coming events with this particular speech, for example - that they also went the extra step of fabricating them too. But I’d be being dishonest if I said that I didn’t greet yesterday’s news with a certain amount of cynicism. I find that a distressing state of affairs; if I had trouble taking what seems to have been a credible threat seriously, it’s no surprise there’s a good degree of ambivalence in the Muslim community. Previous overhyped incidents, such as the ricin “plot” and the Forest Gate raid have significantly eroded trust in the police and intelligence services, even for people (like me) who have no reason to feel singled out or stigmatised. Those times, what we were told in the immediate aftermath did not hold up under scrutiny. This time, the claims about the planned scope and magnitude of these attacks will hopefully be promptly backed up with hard evidence.

(We apologise for the politics, your normal scientific service will be resumed shortly...)

External triggering of volcanic eruptions

2006-08-10T22:49:00.000Z

Phil at Bad Astronomy has been suitably mocking about a BBC story discussing the possibility that last night’s full moon would trigger an eruption of Mount Mayon in the Phillipines (he’s now also noted that it didn’t).

We need to be careful about what this story is and isn’t about. What it’s not about is the notion that a completely inactive volcano is suddenly going to be woken up; it’s more about the potential of tidal forces as a trigger for a volcano which is already predisposed to erupt (e.g. has a full magma chamber under pressure). As the earth rotates beneath the Moon, its gravity not only pulls on the water directly beneath it, but also stretches the underlying crust. The effect is small, but it could be enough to destabilise a finely balanced system and cause an eruption.

If this is the case, we’d expect a statistical correlation between the strength of tidal forces and the frequency of volcanic eruptions, with eruptions more likely when those forces are strongest. These variations could potentially be associated with both the twice daily (diurnal) high tide-low tide cycles, and also the monthly spring-neap cycles, which is what the BBC article is referring to: spring tides occur at full and new moons (for completeness, I should point out that this latter cycle is a result of the changing relative position of the sun with respect to the moon; see here).

As Phil points out, for Mount Mayon there is no apparent correlation:

…the BBC report says that the full Moon "coincided with at least three of Mayon’s 47 eruptions, including the two most recent ones in 2000 and 2001".

…Let’s be generous and say that the time period around the full Moon is 2 days: a day before and a day after. The Moon goes through a complete cycle in roughly 29 days, so it’s full for 2/29 = 1/15th of the time. If you then look at 47 eruptions, then [if tidal forces have no effect] you expect to see 47/15 = 3 eruptions near the full Moon. And hey, that’s exactly what the report says!

In the comments someone posted a link to this article which discusses possible evidence for a link elsewhere, particularly in the eruptive pattern of Stromboli. It’s a puff piece for a documentary though, so there’s no hard data (and I can’t find any publications about it). Besides, if we want to rigorously prove a link, we don’t want to look at the eruptive history of individual volcanoes; we want to look at the global eruption record. This was done in a paper published by Mason et al. in the Journal of Geophysical Research in 2004 [doi]. Their analysis:

We found no conclusive evidence for a general correlation between volcanic activity and lunar tidal phase. This result is consistent with recent work which indicates that diurnal and fortnightly tidal stresses may be too short-lived and strain rates too high to effect a significant viscous response in partially molten regions of the Earth’s subsurface.

In other words, it appears the pressure changes induced by tidal forces are not a significant factor in triggering an eruption. However, the authors in this paper did notice a seasonal variation in global eruption rates. Their Figure 1, shown below indicates that slightly more eruptions start between November and April, compared to the period between April and October. The top subfigure is subdivided according to the eruption size according to the Volcanic Explosivity Index.

This variation appears small but is statistically significant; less clear is the mechanism which drives it. The authors suggest seasonal changes in crustal loading due to variations in sea level, atmospheric pressure, ice and snow cover, and other effects of the hydrological cycle.

Seasonality in eruptions is correlated with environmental fluctuations associated with the deformation of the Earth in response to the annual hydrological cycle, including falls in sea level, millimeter-scale motion of the Earth’s crust, and falls in regional atmospheric pressure.

This would fit in with recent speculations about the effect of melting ice sheets and glaciers on volcanic activity (pronouncements of impending doom notwithstanding).

So it seems that external sources may be able to influence the timing of volcanic eruptions; it’s just that the Moon is not one of them. But how about the other obvious potential influence: the effect of a large nearby earthquake? I’ve actually had a post in preparation for some time about this very matter, which hopefully I’ll follow up with shortly.

Crushed dreams of heroism

2006-08-04T11:10:00.000Z

I usually don't bother to post these online quiz things, but I found the result of this one (via Bad Astronomy) rather apposite. We all dream of being heroes, but it seems that even the internet is insightful enough to know that is not my destiny.

Your results:
You are An Expendable Character (Redshirt)

Since your accomplishments are seldom noticed, and you are rarely thought of, you are expendable. That doesn't mean your job isn't important but if you were in Star Trek you would be killed off in the first episode you appeared in.

Breakdown:

An Expendable Character (Redshirt) - 75%
Spock - 74%
Mr. Scott - 65%
Geordi LaForge - 65%
Leonard McCoy (Bones) - 60%
Beverly Crusher - 60%
Data - 58%
Jean-Luc Picard - 50%
Uhura - 45%
Deanna Troi - 45%
Will Riker - 45%
Worf - 40%
Chekov - 35%
Mr. Sulu - 35%
James T. Kirk (Captain) - 35%

Click here to take the Star Trek Personality Test

And in case you're wondering: yes, but not to the extent that I think learning Klingon is a good use of my time; and DS9, by some distance.

A genuine quake prediction, or inspired guesswork?

2006-07-31T17:29:00.000Z

Via geology.com news, I’ve come across an interesting article in Geotimes about a possible case of successful earthquake prediction:

For nearly three decades after Chinese officials predicted the powerful earthquake that hit Haicheng in the north of China on Feb. 4, 1975, details of their prediction process remained closely guarded. But now, after gaining access to formerly classified documents and key people involved with the process, a team of scientists has reconstructed this important event …

…In this month's issue of the Bulletin of the Seismological Society of America, however, Kelin Wang, a senior research scientist at the Geological Survey of Canada in British Columbia, and colleagues say the prediction was legitimate. The Haicheng earthquake is the "first, and so far only, case where a large earthquake was predicted," says Susan Hough, a seismologist with the U.S. Geological Survey in Pasadena, Calif.

Wang's team reviewed relevant documents and interviewed key witnesses in the prediction process to compile a detailed account of the events and decisions that led to the Haicheng prediction and evacuation. The team wrote that the prediction was "a blend of confusion, empirical analysis, intuitive judgment, and good luck."

The empirical analysis part involved the use of data collected about a series of large earthquakes which hit northern China in the 1960s. It appears that Chinese seismologists identified a number of tectonic events which preceded these earthquakes, which they then started to see again:

By June 1974, based on precursory anomalies that included a shift in land levels in the nearby Bohai Sea area, officials issued the first of two "middle-term" predictions that warned of an earthquake within one to two years.

So far, so scientific, but then we get into the intuition and luck:

No official "short-term" predictions — warning of an earthquake within a few months — were made, the team says, but some Chinese officials made "imminent" predictions, based on an increase in foreshock activity in the 24 hours before the main shock.

A large earthquake is usually not an isolated event, but occurs as the biggest ‘mainshock’ in a cluster of earthquakes in the same region. Aftershocks occur as the crust around the main fault rupture adjusts to the sudden displacement, and sometimes (not always) you get foreshocks as well – smaller earthquakes that precede the main event. The problem is that the foreshock-mainshock-aftershock subdivision is based only on the relative magnitude of the earthquakes in the sequence, and can thus only be applied restrospectively; if you show a seismologist the data from just one particular earthquake in isolation, they would not be able to tell you whether it was the foreshock to a larger event, the mainshock itself, or an aftershock. In Haicheng, it seems the officials saw increasing earthquake activity and decided it preceded a larger event, leading to their warning, but there was a lot of luck involved in this particular ‘prediction’. And it’s not clear whether it can entirely take the credit for drastically reducing the death toll anyway.

Although the imminent predictions correctly identified the quake's location, they did not specify a time, and they underestimated the quake's magnitude. Nonetheless, the predictions — along with some actions taken spontaneously by local citizens [due to education programs initiated after the 1960s quakes]— triggered warnings and evacuation orders around the area where the earthquake eventually occurred. According to the team, the evacuations, along with the durable style of housing construction in the area and the time of the main shock — 7:36 p.m., when most people were neither at work nor sleeping — saved thousands of lives.

Nonetheless, we see once again that the problem is not that there aren’t earthquake precursors (although some are more established than others), it’s reliably spotting them before the event, and understanding what (if anything) they are saying about its imminence.

Detecting extra-solar life

2006-07-27T17:04:00.000Z

There's an interesting post at Dynamics of Cats about the difficult task of detecting the signature of life on extra-solar planets:

This is a hard question: for Earth-like carbon base, photosynthesising life on a low mass planet around a main sequence star, we think we have robust biosignatures - we want to see water vapour, oxygen (or ozone as a more easily detected proxy), carbon dioxide and methane.

However, as the post goes on to point out, early life on earth did not generate this signature, with significant atmospheric oxygen possibly only being present from about 1.5 billion years ago (which leaves a good 2-3 billion years with a different, and poorly constrained, atmospheric chemisty). And that's before you consider non-carbon based life.

The obvious limitation on detecting life outside the solar system is that spectroscopy is pretty much our only tool - the hope is that whatever life is out there will generate a 'weird' (out of equilibrium) atmosphere which we can actually detect. But astrobiologists don't need to look so far before they encounter problems. There's still some argument over the results of the Viking Lander experiments, for example (see here or here), not to mention the whole ALH84001 thing. In both cases the cautious consensus is that there is no conclusive evidence of Martian life, but sorting out life from non-life is clearly not trivial even when we can literally get our hands dirty in the search; no wonder trying to make the determination from light years away is 'hard'.

Lakes on Titan

2006-07-26T16:21:00.000Z

Finally, what we've all been waiting for: possible evidence of liquid hydrocarbons on the surface of Titan:

According to the JPL press release linked to above, these images were taken by the Cassini radar in synthetic aperture mode, which means that the dark and light areas on the image correspond to smoother and rougher areas on the surface, respectively. The dark patches on these images are therefore quite smooth, as you'd expect if they represented liquid; their irregular shape is also quite suggestive. Each of these radar images covers and area of about 450 x 150 km, so if they are lakes they're fairly sizeable ones.

These images are from the north polar regions of Titan, which makes sense; it's colder there, so any methane and ethane would evaporate into the atmosphere less quickly. However, it's not completely clear to me why the scientists are so sure that these features represent currently filled lakes rather than dried up ones, as is the case on most of the surface we've studied so far. Perhaps the radar data indicate a particularly high value of smoothness for these features. Insider gossip from Emily Lakdawalla at the Planetary Society Blog indicates that this might be the case:

Cassini RADAR team member Rosaly Lopes [said that t]he lake-like features are "circular or kidney-shaped and very radar-dark -- the darkest things we have seen. Morphologically, they look much like lakes on Earth. There are drainage features around the sides of lakes."

The rest of the article has a very interesting discussion about the possible origin of the topographic lows that these features seem to represent. There's some evidence that they are collapse structures, so may represent cryovolcanic calderas. The evidence for that is presently fairly equivocal, but if that is the case then these would be the Titanian equivalent of lava lakes. How cool is that?

Graduation

2006-07-25T21:04:00.000Z

As of yesterday, I am officially a Doctor. I have the certificate and everything.

I'm still shaking my head with amazement about that gown. As well as being a little confining on what was another very warm day, it makes me look like I'm a member of an ecclesiastical football team (by ironic coincidence, following semi-family tradition I vaguely support West Ham United). Those of you looking for the silly hat, fortunately we didn't have to wear that in the ceremony itself, although to keep Mum happy I wore it for the official photo.

I was discussing the total ridiculousness of this attire with a friend at work today. As well as claiming that I'd got off lightly (I'm hard pressed to see how, mind), she proposed the highly plausible theory that it is just the Universities' way of putting us upstart graduands in our place. As she put it:

"It's like they're saying: you think you're so smart? We can still make you look ridiculous"

So, the final postscript to my PhD? Perhaps, but it left me a bit cold - who cares about a certificate when you have the thesis on your shelf? Curiously though, I found that all of the major events at the end of my tortuous academic journey - submission, viva, final submission - have turned out to be somewhat anticlimatic. I'm not sure why that is. I think part of me feels that despite passing my viva, and even despite having published a large chunk of the work I have done thus far, the verdict on my work is still out - I'll only start to feel happy when I see it being cited by other people. But perhaps part of it is also that like life, the journey - the process of doing a PhD - is more important than the actual destination. Although NERC would add that you still need to get there, within four years if you don't mind very much.

Discrimination!

2006-07-20T22:16:00.000Z

I took a few days off at the end of my Spain trip to visit the Picos de Europa. It seems that they don’t want my sort around:

I’m not sure they need to worry so much – for a start, most of it is limestone, and not particularly fossiliferous limestone at that. Also, the scenery is good enough to pull even my attention away from my feet:

Latest earthquake in Java

2006-07-19T17:00:00.000Z

Monday saw another tsunami hit Indonesia, triggered by an earthquake offshore. But what more can we say about this quake? We can immediately use our knowledge about earthquakes and plate tectonics to make some basic predictions:

The earthquake will probably be due to movement along a thrust fault, probably associated with the Sunda trench. Tsunamis are caused when vertical (up and down) motions of the ocean bottom associated with an earthquake displaces the water above, creating a large wave. Vertical motions occur on contractional (thrust) and extensional (normal) faults. Java is close to a convergent plate boundary, so the earthquake is most likely to be on a thrust fault associated with this subduction zone.

The epicentre will be shallow. In order to cause a tsunami, the fault rupture must have propogated up to the ocean bottom, suggesting that it initiated at a fairly shallow depth.

Here's the USGS moment tensor solution:

Lo and behold, a shallow thrust (6 km may not seem particularly shallow, but at a subduction zone you can get earthquakes down to several hundred km) close to the Sunda Trench. The beachball like focal mechanism shows a thrust, and is very similar to that for the Boxing Day 2004 Earthquake (see also my previous post on seismology in this region).

Thus we have simulataneously demonstrated both the power and the impotence of plate tectonics at present. The fulfilment of my predictions shows that this earthquake fits in well with our overall tectonic picture of the region, but it is only a retrospective understanding; on Sunday, there was no way of predicting that an earthquake of that particular size would occur in that particular location.

Energy review says nothing much

2006-07-18T21:56:00.000Z

Oooh, the government must be afraid of me. Why else would they choose to wait until I was away to release their new, improved energy review? Get the full details here. I neither have the time or the inclination to wade in detail through its entire 218 pages, but I have done more than skim through the executive summary; and, in contrast to the OTT pro-nuclear rumblings being put about by certain people, it does at least have some semblance of balance. In fact, contrary to the ‘back with a vengeance’ rhetoric, I find it a bit wishy-washy and non-committal. For example, the heavily-leaked nuclear stuff: as has been widely expected, the review concludes we need to build some new nuclear power stations, but doesn’t seem anywhere to suggest how many it thinks we might need. This might be why:

It will be for the private sector to initiate, fund, construct and operate new nuclear plants and to cover the full cost of decommissioning and their full share of long-term waste management costs.

Nothing to do with us, high gas prices will mean the private sector will be queuing up, no public money needed, oh no! Whether you think more nuclear is a good idea or not, I think we can all agree that this at best disingenuous. Decommissioning and waste storage issues are also somewhat glossed over (although to be fair, this is no change from the last 60 years or so).

One pleasant surprise is that there’s a whole chapter devoted to distributed energy generation and CHP which is actually reasonably positive, highlighting the potential benefits (which I’ve discussed before) as well as discussing potential downsides (possible loss of economies of scale, problems with fully exploiting offshore wind and other renewable resources). In the end, however, there is a disappointing, but predictable, commitment to not very much at all in this area:

To understand its true long-term potential, and the challenges we face in getting there, we will commission a high-powered investigation of the potential of distributed energy as a long-term alternative or supplement to centralised generation, looking at the full range of scientific, technical, economic and behavioural issues.

In a similar way, domestic energy usage and transport are referred to, but not in a way that lends confidence that the government is going to provide much in the way of leadership in these important areas. Even the warm and pleasing tones about renewables obligations are slightly marred by the fact that whilst wind is mentioned a fair amount (116 times in all compared to 441 for nuclear) solar and tidal energy get hardly a mention (17 and 11 times respectively).

It’s hard (especially in the current heatwave) to get really mad about something so fundamentally unambitious. Climate Change Action summarises some disappointed reactions from the likes of the Sustainable Development Commission and the Tyndall centre (pdf).

Geo-porn blog shocker

2006-07-18T12:29:00.000Z

Now here's something a little disturbing: my blog is first up in Google for the search term 'pictures of scantily clad women'

Don't believe me? See for yourself - this post is first up. I discovered this rather curious fact when looking through my blog referrals in Sitemeter; I somehow don't think that that particular visitor got what he was looking for. I can only assume that this turn of phrase is too subtle for all the real X-rated sites. How quaint I am.

Update: It appears that putting 'porn' into a post title also does wonders for your traffic too (at least by my meagre standards).

Back from Spain...again

2006-07-17T12:20:00.000Z

Yes, it truly is a hard life. No sooner am I back from one trip to sunny Iberia, it seems, than I get sent off on another. This time I was out in the Cantabrians in Northern Spain, to get 2nd going on 3rd years started on their independent mapping. More specifically, we were letting them loose around the towns of Villamanin and La Pola de Gordon, just north of Leon.

Back in my day (which doesn't feel that long ago, until I actually reflect on it and realise it was the end of the last millenium; several of the students are conspiring to make me feel old by having their 20th birthdays whilst out there) I got no such help, but given the complexity of the area, I don't begrudge the students some assistance. The rocks consist of a sequence of sandstones, limestones and shales, ranging in age from the Middle Cambrian (~550 million years ago) to the latest Carboniferous (~280 million years ago – here’s a timescale for your convenience), which were deformed mainly in the Variscan Orogeny (the uppermost units were actually deposited during or after this mountain building event). This has resulted in some quite complex geology. The picture below looks south from one of the highest points in the region:

The high ridges you see extending into the distance are pretty much made up of the same rock unit – the massive Barrios quartz sandstone. The fact that it keeps on appearing indicates the presence of many thrust faults which have caused the same sequence of rock units to repeat itself a number of times. Further to the south ridges of younger limestone also appear repeatedly. This photo is in fact taken across a massive fault: I’m standing on a Carboniferous limestone which is right next to the much older (Ordovician) Barrios, with most of the intervening units missing.

An additional wrinkle is illustrated by a second photo, which shows some very well preserved ripple marks preserved on the steeply-dipping bedding surface of a sandstone. You could find something similar on any beach today – but these ripples formed back before tetrapods were a twinkle in some ancient lobefins’ eye (if that makes no sense, have a read here or here).

But what’s puzzling here is that you’d expect to find these structures on the top surface of a bedding plane, and here they’re on the bottom. The deformation in this area has been so extreme that this bed has been overturned. In fact, in most places where sedimentary structures or burrows are found in this area, they indicate that the units are upside down. That’s some extreme deformation for you.

All of this gives our students plenty to mull over, and is why this region is a popular mapping area for many universities – in the last fortnight we met people from Imperial, Oxford and Dublin also wandering through the area. But given that the area is so sliced up by faults, it seems only fair to make sure the students know what the actual stratigraphic sequence is supposed to be (so they can spot missing and repeated sequences). We did this in a couple of induction days with the whole group, before some more individual tuition: pairs of students are mapping different, and separate, areas (for safety – they have to make their own observations and interpretations), and I went around with each of my groups individually around their area to make sure they had their eye in on the different units, and to check that they understood the process of mapping. It seemed that my efforts to provide some general clues on how to approach things were not entirely in vain - even before we left I saw some field slips with boundaries being drawn on, and many of the students I am supervising at least seemed to be asking the right sort of questions, even if their attempts to answer them were sometimes a little off-base. Of course, this year's lot may just be better than last year's, and it's nothing to do with me whatsoever, but I'll cling to the illusion that I was helping to make a difference. Of course, the real test comes when I see the finished results at the end of the summer...

What's hot in the world of science?

2006-06-27T18:15:00.000Z

I've just discovered the nifty new "Most Popular Now" page on BBC News, which shows you which stories are getting the most attention worldwide, or region by region. You can even check by subject - for example, as I write the top science and nature stories involve a 'chameleon' snake and another depressing set-back for the EU emissions trading scheme (though it's Germany, rather than the UK, in the dock for once).

Wouldn't it be good if instead of the general public, you could discover what was exciting scientists? Nature offer a list of the month's ten most downloaded articles, but sadly (and not surprisingly) biomedical stuff seems to dominate to the exclusion of all else. Better is the Top25 portal at ScienceDirect, where you can search by subcategory and individual journal (I think you can at least access the abstracts of the listed papers without a subscription).

This is a very crude tool, because a better measure of whether a particular paper has excited scientists is how much they use the ideas and results to guide and augment their own work, which is measured by citations. Tracking who is citing whom is a bit more difficult than counting downloads or page hits, so freely available information seems a bit limited: Thomson Scientific runs in-cites, which offers the top three 'hot papers' published in the last two years in various fields, and also a list of 'super-hot' papers which seem to be garnering special attention. However, although this is interesting, I don't know how much use it is for me as a scientist - within my field I can learn a lot more by getting down and dirty at Web of Knowledge, and searching for papers in the Science Citation Index, which cross-links every paper published in the last 25 years to the ones it cites and the ones it is cited by. Having an internet connection on my desk is a mixed blessing, but every minute of my day that is wasted through mindless web-surfing is more than compensated for by access to that sort of information.

How to stop worrying and love your mapping project

2006-06-26T17:40:00.000Z

As I may have mentioned, prior to my holiday my life was taken over by marking and viva-ing a breeding population of undergraduate mapping projects. These projects are a major part of the third year, and are a required component of any certified geology degree, and in a week’s time, I’m heading out to the Cantabrians in northern Spain to get some of next year’s students started on their 30 days in the field. As a preparation for that, I’ve written a list of tips and pointers collated from weaknesses (and strengths) I perceived in the projects I marked; the comments of the external examiners at the exam board meeting I sat in on last week; and reminiscences of my own mapping project, way back in the summer of 1999, which I used to guide my marking (as per usual, the guidance I was given by the department was a little…. sparse). It’s probably not of particular general interest, but you never know.

The aim of mapping

The ultimate aim of the project is not the map. Your goal is to uncover the geological history of the mapping area, principally:

The sequence of deposition of the different formations, and the environmental and tectonic changes which have produced these distinct rock types.

The structures (faults and folds) which have led to the present distribution of the different formations, and the tectonic events which produced them.

A good map is essential for developing this understanding, but if you confine your fieldwork to simply colouring the distribution of outcrop, you’re making it difficult for yourself.

Thinking and hypothesising in the field

There are various scales of observation to consider when you’re recording the geology at a particular locality, from whole outcrop to hand lens. When mapping, you also have to think about the biggest scale of all: regional context. As well as the obvious (e.g., ‘this is 200m downstream from the last locality’), you should always be asking yourself, what’s going on at this locality compared to the last one you saw, and others nearby? Can you explain any changes in rock type, or structure? It is especially important to properly record such observations. If a formation you don’t expect suddenly appears, note down that it’s unexpected. Record and sketch any ideas you might have about what’s going on, and what you might find at the next outcrop if your idea is right. Then go and have a look. Even if you never do field geology again, this is great experience of doing real science.

Field slips as working documents

Field maps are not something to passively colour in outcrop on; you should be trying to infer boundaries, and drawing them on, as early as possible (the same is true of faults, folds etc.), preferably as you are mapping them. Doing this turns your field slips into a powerful tool to guide your mapping, allowing you to visually check, whilst you are still in the field, whether what you are observing makes geological sense, and highlighting areas that you will need to concentrate on to sort out what’s going on. It’s far easier to do something about problems and missing data out there, than months later back home.

Annotation of your field slips is also important – if you’re inferring a boundary due to a break in slope, or a change in vegetation, then record this on your field slip. If you have observed a good exposure of a fault plane, or an unconformity, highlight it. All of this tells a marker that you are doing geology, rather than colouring in.

Don’t be a slave to the literature

In your final project, you will be expected to justify all of your conclusions and interpretations in terms of what you have actually observed in the field. It's fine to compare what you have seen to what is stated in the literature, but published research is not a substitute for your own observations – even (especially!) if they disagree. Like any geologist, the authors of papers about your mapping area have pieced together the history of the area from incomplete information, inferring boundaries and structures where there was no exposure. What is more, their research usually encompasses a much larger area in far less detail, meaning that the observant undergraduate might well see features, structures, and even outcrop that they did not. This new information might change your interpretation completely, indicating that in your area at least, things were different from the published interpretation (you should also bear in mind that general conclusions for a larger region may not be a good fit for your specific area).*

Observation and interpretation in your notebooks

Third year students shouldn’t need reminding about separating interpretation from observation, but they do need to be aware of the biggest enemy they will face in their 30 days in the field – boredom, the effect of which is to make people forget about the observing part and move straight on to the interpretation.

Day 28, and you come across an outcropping of limestone. It looks like a formation you’ve seen a hundred times by now, it’s about where you expect it to be. You write in your notebook, “Locality 278. Exposure of Intractable Limestone Formation,” record any structural information, and move on. The only problem is, assigning a formation is an interpretation, and it has been written down without recording the lithology, fossil content, and other observations which explain why you think it is that formation. Months later, you start to suspect that at that outcrop it was the Inscrutable Limestone instead of the Intractable Limestone. If you have recorded your primary observations, you can check this – you may see that at this particular outcrop you didn’t see the fossils characteristic of the Intractable, making it possible you misidentified it. If you just have a formation name, you’re stuck.

So work hard to maintain the quality of your notebook. After 30 days, you can’t possibly remember everything you’ve seen in your area; you will need to have it all written down so you can refer back to it.

What you should (and shouldn’t) be doing in your evenings

There is a growing trend for students to put very little on their maps, and sometimes even in their notebooks, in the field, only to waste hours reproducing immaculate versions of what they have seen in the evenings. What you will get for all this effort is suspicious markers, who want to see evidence that the field slips are being used, as I have already discussed. Filling in as much information as possible as you go means that in the evening all you should have to do is make sure that everything is legible and inked in, freeing up time for what you should be doing, namely thinking. Did you understand what you have seen today, or are there still areas you don’t grasp? Does it fit in with your current understanding of the whole area? It goes without saying that you should write down these thoughts in your notebook.

Cross-sections

Ah, the term which strikes fear into the heart of every undergraduate - which is all the the more reason not to leave it until you’re writing up before thinking about them. From the very beginning you should be devoting some of that evening thinking time to sketching cross-sections. Amongst other things, this is another check on whether you’ve mapped things correctly – projecting things into the third dimension can reveal problems which aren’t immediately obvious in plan view.

Although within a week you should have enough information to produce a reasonable first stab at a section through your area, a fully accurate one will require a lot of structural data along the line of section. It is a really great idea to select a sensible cross-section line (or lines) before you finish in the field, then take a day to traverse it (or them), checking that what you see agrees with your map, and that you have enough structural data to properly constrain things. Again, this can reveal problems with your map which are much easier to fix out there than back here.

Sketches or photographs?

Both. If you have a digital camera, it’s very tempting to rely on cold hard optics rather than your own sketches, and it’s certainly true that a photo can record more detail, more accurately, than all but the best of us can manage with a pencil. But there is a lot of interpretation involved in the process of sketching – you are picking out and highlighting the most important features of the outcrop. You can’t do this when taking a photograph, which means that when you look at again it’s very easy to forget what it is supposed to show. A photo cannot replace a sketch, but it does complement it, and vice versa.

Small-scale tells us about large-scale

Because rocks tend to deform at all scales, clues to the overall structural style of an area can often be found by looking at features of smaller scale folds (e.g., shape, vergence) and folds (e.g., orientation, sense of displacement from slickensides). Detailed measurement of these features can be very useful.

So endeth the lesson.

*I didn’t get anywhere with my own mapping in North Wales until I folded up the BGS sheet for the area and put it at the bottom of my bag for the rest of my trip. It just wasn’t at a small enough scale to properly represent all the details I was finding – for example, it had a lot of random faults running through my area, when I thought there was a lot more regularity there. As it turned out, there was.

What makes a good science teacher?

2006-06-25T11:41:00.000Z

Not content with assimilating science-inclined bloggers left, right and centre into the looming Scienceblogs collective, Seed Magazine also regularly demand tribute, asking them all to answer weekly questions in their own idiosyncratic styles (see here for previous examples). This week’s asks, ”What makes a good science teacher? All the responses will be eventually collated here, but as this is a question that I have been struggling with for the last 10 months or so, I thought I’d just point out some common themes in the answers so far, and add my perspective on them.

Corturnix at A Blog Around the Clock says that one of the keys is to know your subject.

Knowing your material inside and out, at least a hundred times better than the students or the textbook - that certainly helps, not just in answering potential questions, but also in the degree of self-confidence one brings to teaching.

This is especially important for me, because I’ve found it almost impossible to use pre-written notes effectively; even if I have them, once I've started talking I forget that they are there. And whilst this potentially leads to a much more flowing lecturing style, it’s also much easier to start rambling if you don’t know the material inside-out.

More importantly, I’ve found that you can understand a concept well enough to use it every day, and that still doesn’t mean you can teach it effectively. Your route to understanding something often involves all sorts of mental short-cuts which make perfect sense to you as a (relative) expert, but will quickly lose a novice. Spotting these is very important; as Jason Rosenhouse at EvolutionBlog puts it:

The key to good teaching is an ability to put yourself in the position of someobody learning the material for the first time.

Mike the Mad Biologist agrees:

A good teacher has to know what students don't know.

Or, as someone told me to my chagrin on a field trip (regarding some lectures I’d done the previous term):

You came across as knowing what you were talking about, but that didn’t mean we always understood it.

Sometimes that isn’t just about poor explanations though, it could be that the students can’t work out what the point is. As the Evil Monkey opines at Neurotopia:

If I had to decide what makes a good science teacher, it would be the ability to demonstrate how experiments fit into the proverbial "scheme of things". Nothing kills interest in science faster than 1. not being able to accurately relay the structure of the big picture and 2. just tossing a bunch of apparently random experiments at the students and expecting them to figure out how the pieces fit together. You wouldn't attempt to put a jigsaw puzzle together in the dark, would you?

Concurrently, at Good Math, Bad Math, MarkCC says (about maths teaching, but I think this is generally applicable to all sciences):

But it's very easy to get caught up in the abstraction, and forget why you're doing it. Good math teaching is a subtle act of balance: you're studying abstractions, but you need to keep the applications of those abstractions in sight in a way that lets your students understand why they should care.

Case studies, drawing examples from published research to show how the concepts you’re talking about are tools, with clear uses, are important in this regard (in geology, I’m helped greatly by the fact that it’s not usually too difficult to link even the most theoretical stuff to the ‘real world’). In lectures, narrative is a great way to hold attention: show a problem which scientists set out to solve, before showing that the concepts you’re teaching about were essential in solving it. Such a structure also naturally incorporates insights into how science works, which Dr. Free Ride at Adventures in Ethics and Science thinks is the most important thing of all:

In the grand scheme of things, the most important knowledge for the science teacher to transmit has to do with methodology rather than a laundry list of facts (especially since lots of the facts get updated). And the methods of scientific inquiry are not completely divorced from common sense. Building on the continuities between the two is a good way to get the kids who may not grow up to be scientists a good appreciation of how science works.

And I’ll give her the last word too, as she admonishes those of use who fall back on the old ‘science is hard’ shctick to compensate for the fact that only the really bright ones seem to follow you.

… if you're a teacher, your goal when you walk into the classroom should be to teach all the students whatever it is you're charged with teaching them. We don't always meet our goals, but dammit, at least try!

*blush*

UK's green credentials questioned again

2006-06-23T08:24:00.000Z

From New Scientist:

MANY governments, including some that claim to be leading the fight against global warming, are harbouring a dirty little secret. These countries are emitting far more greenhouse gas than they say they are, a fact that threatens to undermine not only the shaky Kyoto protocol but also the new multibillion-dollar market in carbon trading.

The article describes some work from the Insitute for Environment and Sustainability at the European Commission Joint Research Centre (Peter Bergamaschi, the lead researcher, has a home page here - although there is no information on this story at either of these links yet). The research is based on direct measurements of atmospheric methane concentrations around the globe, which are then combined with atmospheric modelling.

[Using this technique] scientists say they can calculate a country's emissions independently of government estimates. Bergamaschi's calculations suggest that the UK emitted 4.21 million tonnes of methane in 2004 compared to the 2.19 million tonnes it declared, while France emitted 4.43 million tonnes compared to the 3.01 million tonnes it declared.

Such underestimations are significant in the context of both the Kyoto Protocol and emissions trading schemes:

"Now that money enters the picture, with the Kyoto protocol rules and carbon trading, so also can fraud. There will be an incentive to under-report emissions."

Cynical as I am, I'm ready to give the benefit of the doubt in this instance - estimating emissions is not an easy task, especially for methane where the major sources are landfill sites and peat bogs rather than power stations (although it seems that the government is not exactly jumping over itself to try and improve the monitoring). The real test will come now that these results have been publicised - will the government admit the possible underestimation and revise their figures? I'd also be interested to know whether a study of carbon dioxide would produce similar results.

Are we running out of Uranium?

2006-06-21T16:32:00.001Z

I’ve just seen this post over at Bunsen Burner which discusses the case for new nuclear build, and which I heartily agree with (mainly because I’ve come to the same conclusions, albeit in a less concise manner). Whilst it’s always nice to see people agreeing with me, I was interested by the following sentence:

There is only so much uranium in the world and even with reprocessing this power source will run-out at some point. So wouldn't the money better be spent on something a bit more long term?

Which got this comment in response:

There is a significant body of work that disputes your conclusions about the global uranium supply.

Does this mean that somebody somewhere is seriously arguing that uranium supplies are renewable? Entertaining as that would be, it would seem not. Instead, the the link in the above comment is a post responding to claims (in a Guardian article which I missed) that the uranium supply is already on the verge of being exhausted. So, whilst the comment is a slight over-reaction in the context of this particular post, it does raise an interesting issue. So what are the facts?

Resources:
A recently published IAEA report (home page here - except for the one exception listed below all the figures I use come from here) estimates the known inventory of uranium extractable at current market prices to be about 4.7 million tonnes, and total estimated reserves to be about 35 million tonnes. An estimate from what could be regarded as the other side of the fence is provided by van Leeuwen and Smith, whose work I’ve referred to before, and who estimate 4.3 million tonnes of ‘useful’ reserves with little hope of new major ore bodies being discovered (Chapter 2 from here). So a lower limit of about 4.5 million tonnes seems well-supported; estimating an upper limit is fraught with the usual difficulties you get when guessing how much you haven’t discovered yet, but we could probably take 35 million tonnes as an optimistic upper bound (I’m not sure how these figures would be affected by economic considerations, but it looks like it includes stuff which cannot be profitably extracted at current prices).

Production and Usage:
The IAE report says that mining produced 40 000 tonnes of Uranium in 2004. About 67 000 tonnes was actually used in nuclear power stations, with the shortfall coming from ‘secondary sources’ (stockpiles, reclamation from decommissioned nuclear weapons, some reprocessing). These secondary sources are being depleted, so we’re going to rely more and more on primary production in the future.

Doing the sums, if it’s all coming from primary sources the supply will last 65-500 years at the present rate of consumption. But demand is expected to increase to as much as 100 000 tonnes/year by 2025 (based on proposed new build, which probably doesn’t include any hypothetical new UK stations), reducing the supply lifespan to 45-350 years. That is, if we can actually supply 100 000 tonnes/year; by 2010, up to 30 000 tonnes/year may be added by mines currently being or planned to be developed. This still leaves a bit of a shortfall, but we’d have 15 years to address it.

So, on current trends it would appear that there’s no real supply problem, at least not in the lifetime of the next generation of power stations. But the key phrase is ‘on current trends’, because the whole point is that there’s a lot of debate (and hence uncertainty) over the future of nuclear power. For example, if we embark on a massive nuclear building program to replace fossil fuels, all these sums get skewed towards rather lower supply lifetimes. This would be a concern, but not an insurmountable one; my chief objections have always been, and remain, the questionable effectiveness of the nuclear option in solving the problems of greenhouse gas emissions and energy security.

On hiatus

2006-06-12T08:08:00.000Z

Right, I'm off for a well-deserved break, to enjoy the fabulous geology (sorry, scenery) of the fair Isle of Skye. When I'm back, hopefully my life will be less mad and I can get back to posting more regularly.

Permian crater in Antarctica...maybe

2006-06-12T07:47:00.000Z

I was way too busy last week finishing off marking and vivas to comment on this story about the possible discovery of a 300-mile wide impact crater which seems to be about the right sort of age to have possibly contributed to the Permian extinction, an event 250 million or so years ago which wiped out about 90 % of all species on Earth (see here and here for some discussion and links).

The method is indirect, using the GRACE gravity satellites (which I've mentioned before) to find a positive mass anomaly beneath Antarctica which seems to indicate a massive upwelling of material from deep in the Earth. This has been linked to a ring like structure beneath the ice (pictures here).

Dean Armstrong points to a Nature article which emphasises that there is as yet little direct evidence of this being an impact structure. In particular there is little evidence in Antarctic Permian rocks (at least, those which aren't under lots of ice) for any sort of impact - no ash flows, impact breccias, or megatsunami deposits which can be found around the KT impact site. Which leads to another thought: the researchers tried to make a link between their putatative crater and the mantle upwelling, and the fact that this is close to the rifting event that began the break-up of Gondwana. If there is no crater, this may not be support for the (controversial) idea that large impacts can cause rifting, but instead could be telling us something about the internal processes that triggered that rifting.

Volcanoes from space!

2006-06-05T13:31:00.000Z

Via Bad Astronomy, here's a rather cool picture from low earth orbit of an ash plume erupting from Cleveland volcano (part of the Aleutian arc, and therefore a little bit lost).

This image was released by NASA's Earth Observatory (there's also a high-resolution shot available) and was taken by an astronaut currently on the ISS. As has been observed, this may be one of the more significant scientific contributions made by this $multibillion orbiting albino pachyderm. Yes, it is a pretty cool photo - but we have a lot of satellites out there who do this Earth observation thing full time, rather than just when they get the chance to peer out of a viewport. As an example, here's a couple of satellite images showing similar activity at Mount Merapi, in Java (which has been hitting the headlines recently). The second is a thermal image:

(images from here and here, respectively).

And, now that NASA is introducing software which allows its probes, rovers and satellites to independently direct their instruments towards interesting events (more details here), you can't even say that humans have the monopoly on choosing when to take the cool photos.

Earthquake in Java

2006-05-30T13:28:00.000Z

When they first heard news of Friday's earthquake in Java, many people's first reaction was undoubtedly to wonder if this latest event is in any way related to the Boxing Day 2004 quake. Here's some information on Friday's earthquake, courtesy of the National Earthquake Information Center (more specifically, here):

This image shows both the earthquake's location and a beachball-like symbol, known as a focal mechanism, which indicates the type of fault generating the earthquake. More in this in a minute, but first lets look at the same information for the Boxing Day Earthquake (full summary here).

You should ignore the magnitude, which was actually 9.0 - the automatic system which generates this information estimates magnitudes from the amplitude of seismic waves of a particular type and frequency, which are saturated (can’t get much bigger) for very large earthquakes and hence lead to an under-estimate.

The Boxing Day tsunami was caused by a rupture of the subduction megathrust at the boundary between two tectonic plates, just off the Indonesian coast. This is obvious from the fact that the hypocentre (point of first rupture) is very close to the Sunda trench, which is where the megathrust breaks the surface. It is also obvious from the focal mechanism, which is an idealised plan view of the movement associated with the earthquake, divided into compressional (solid areas of the beachball) or dilational (white) zones. This distribution is constructed by combining the directions of first motion, compared to the direction of the source, received by the global seismometer network; this will vary depending on the relative position of the station. The dividing lines between the solid and white zones represent the two possible fault planes along which this motion occurred - movement along either of these planes can produce the same focal mechanism (for slightly more detail, see here or here). The focal mechanism for the Boxing Day 2004 earthquake is a thrust fault - there is a compressive zone in the centre of the beachball which shows that shortening of the crust is occurring along either a very steep, or very shallow, thrust plane. Because we know it was at a subduction zone, it's probably the latter (the megathrust is normally shallowly dipping - see my previous post on subduction zones).

However, looking back at the information for Friday's earthquake, you can see that it is located much further away from the trench, in the forearc region of the overriding plate. Also, the focal mechanism is completely different; the pattern of compression and dilation implies horizontal strike-slip along a vertical fault plane. This indicates that this earthquake did not occur at the megathrust on the plate boundary.

However, things start to get interesting if we look at the relative motion across this boundary, which, as the figure below indicates, is generally oblique to the trend of the Sunda Trench. In contrast, the motion at the subduction megathrust (as indicated by the Boxing Day focal mechanism, and the focal mechanism of the 28th March earthquake in the adjacent section of the subduction zone) is almost exactly perpendicular to that trend. It seems that motion along the megathrust cannot account for all of the relative plate motion. However, the 'left-over' motion (see inset) can be accommodated by events like Friday's earthquake, if we assume a NW-SE-trending fault.

This phenomenon - different parts of the plate motion being taken up by separate sets of faults - is known as strain partitioning, and is very common in regions of oblique subduction. Thus the two events can be viewed as complementary - the strike slip fault in the forearc region is taking up the component of plate motion that the subduction thrust does not. The Boxing Day earthquake did not directly cause Friday's earthquake, but a study of its focal mechanism clearly requires events like it.

Viva'd out

2006-05-27T23:17:00.000Z

Last week I finally managed to break the back of all my marking and, most importantly, the viva-ing. I've ended up doing much more than I expected, mainly because I rather foolishly agreed to cover for the single person in the department who is taking this whole lecturer strike seriously, more than doubling my workload at a stroke. The powers that be are paying me extra for this, but at several points in the last week or so I've wondered whether it was really worth the lost weekends and evenings.

The vivas themselves were an interesting experience. I have to confess to feeling a slight discomfort with the whole thing; here I was, passing judgement on the efforts of people I don't feel much older than, with my opinion having equal weight to that of the other, much more experienced marker. I did worry that they might chafe a bit at the situation, but that didn't seem to be a problem. For my part, it was interesting to see how the second markers focussed on different things in the vivas themselves. Some concentrated on narrrow technical issues, others on more general interpretation stuff - there was almost as much variety here as in the how the students coped. On that side of things, there was surpises both pleasant and unpleasant: it was great when they came in well-prepared, and showed a much better understanding than you expected, it was less good when they came in and threw random keywords together in the hope that some glimmer of sense would emerge (in much the same manner that many of them seemed to have written their reports).

As well as all of that, I also had to give a double lecture last Friday, ironically to the same third year who I have been viva-ing. It was also the last lecture of the semester for them (and hence for some, their last lecture ever), so there was a definite 'end of term' atmosphere which probably didn't do much for their attention spans. Still, hopefully I did enough to ensure they ended on a medium.

Anyway, I can't complain about not having anything to do at the moment, that's for sure, and my self-indulgent vanity projects (to wit, this blog) have suffered as a result. Hopefully I'll get back to having some spare time soon.