Historical seismometers #2 - Galitzin

This is the second post in a series on my favorite seismometers on display at the Seismology Museum in Strasbourg. After the Weichert seismometers, let's look at something smaller, but no less spectacular: the Galitzin vertical and horizontal instruments (1910).

Built in St Petersburg in the early 20th century by Boris Galitzin, an inventor and prince of the Russian Empire, these instruments are the first to be based on the principles of electromagnetic induction.  The photographs below show first the vertical, then the horizontal instruments in the museum.  [Photos by Michel Dufloux]



The important innovation in these instruments compared to purely mechanical seismometers resides in the coil placed at the far end of the pendulum's rod. This coil oscillates in a magnetic field and by its displacement creates an electric induction current. A copper plate, fixed to the same rod as the coil, oscillates in the field of a second magnet and allows for electromagnetic damping. The induction current from the coil is transmitted to a galvanometer equipped with a mobile frame and a mirror. A beam of light shed on the mirror records the deflected beam on light-sensitive paper. You can find schematics of the horizontal Galitzin on this Seismology Museum page and also on this IRIS page.

The two instruments in the photographs were made in Saint-Petersburg, and were in use in the Strasbourg seismic observatory from 1910 to 1975. The masses are 10kg and 7kg respectively for the vertical and horizontal components, with natural periods of 24 and 12 seconds respectively. Comparing this with the characteristics of the Wiechert seismometers (1000kg, 8s period) shows that the Galitzins are lighter than their ancestors by a factor of 100!

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Peer review icon contest

Ten days ago I wrote about an initiative to standardize and aggregate posting on peer reviewed research in all subjects. This initiative has now developed into a fledgling organization called BPR3 - Bloggers for Peer Review Research Reporting.

There has been a lot of activity over at BPR3, discussing working definitions of peer-review, the requirements for an icon to specifically indicate that a post is about peer-reviewed research, the practicalities of aggregation of such posts.

Now for the latest: the BPR3 Icon Contest :

Bloggers for Peer-Reviewed Research Reporting is pleased to announce its contest for designing the icon that will represent the organization and its mission on academic blogs world-wide.

Contest participants will design a universal icon that everyone can use on their blog posts whenever the post is a serious commentary about a paper published in a peer-reviewed journal, and not just a link to a press release or media commentary.

Eventually these posts will be collected on BPR3.org, so anyone can find the most thoughtful blog posts on the internet, discussing serious research, not just media hype.

The deadline for submissions is September 10th. All submissions are welcome, but please read the icon specifications and contest rules on this post before rushing off to your design table.

Expedition planning #4 - Pinching pennies and time contraction

It has been a while since my last expedition planning post, a rant on the purchasing jigsaw. The reasons are that plans were up in the air for some time, as important variables kept changing. Now things have settled down enough for me to attempt to fill you in.

First off, funding: in a previous post, in which I enthused about the CASE-IPY project being selected for funding, I wrote that we did not as yet know what level that funding would take. We now know that we have been allocated 80% of what we asked for from the ANR (Agence Nationale de la Recherche).

We have been spending the last week or so trying to figure out how to get the project done with a 20% cut in budget. Never have I appreciated more the usefulness of spread-sheets. I had always been skeptical about their real place in science. In my opinion, complex math should be done by writing code, and data should be kept and analysed using proper databases. That left little space for the spreadsheet. However I have been forced to concede that OpenOfficeCalc is the tool of choice when it comes to dealing with budgets.

One week of turning the numbers all possible ways has led us to drop one proposed station out of the eight we were planning to purchase with the ANR money. This allowed us to reduce the logistical cost of the operation a little. We have also had to remove all IT equipment from the budget, as well as all publication costs. We will be walking on a tightrope for the next three years, but at least we can go out there and do this thing!

This summer's campaign is starting to come into focus a little more, now. We had already shipped a case-load of batteries out there, and at the beginning of August we shipped out insulated boxes of our own design, more space-filling insulation, insulation for cables, and of course the solar panels that will be our energy source for the duration of the Antarctic summer. We have shipped enough to set up three test stations. We will be monitoring their performance remotely, and will use the information we get back to improve the station design for the full deployment which will happen next year.

The dates for this summer campaign are now much closer to being confirmed as those I originally posted about. However, the 4 weeks of Concordia time we had asked for have been reduced to 3 weeks, for logistical reasons, so we will have to make more efficient use of our time up there.

Summary of the present situation: we've taken a 20% cut in funding and a 25% cut in field time, but we are still going strong.

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Antarctic winter - the end begins

Two weeks ago we started to have sun-up at some coastal Antarctic stations, an event which led to a few posts from Antarctic bloggers summarized in my first and second blog post reviews (you can find the original posts here and here and here).

This week, posting has been rather slow, something I ascribe to the preparations for the end of isolation at the bases. In fact, this week both Scott and McMurdo base have been visited by their first flights of the season. This is an occasion for celebration after 6 months of darkness and isolation.

From the 70South article on Scott Base, it seems fresh food is top of the agenda:

Finally, the six months of isolation have come to an end for the 20 staff who are stationed at New Zealand's Scott Base. After such a long time, the supply of fresh fruit and vegetables have long since been consumed.

However, they will still have to be patient a little bit longer as fruit and vegetables are not due to arrive till Friday. When asked to fill out a wish list, the requests were very varied, from raw carrots to crumpets or melons

At McMurdo too, food and external human contact are top of the agenda, according to 70South.

The scientists and other personnel from the American McMurdo Station have been longing for this. Finally, after five and a half months of isolation during the Antarctic winter, the first plane flew in with fresh supplies and passengers.

[...]

“We bring people down that will begin construction on what is called the annual sea ice runway,” Lt. Col. Jim McGann, 304th Expeditionary Airlift Squadron commander, said in the release.

With all this ado, it is not surprising that writing blog posts is not really the highest priority out there right now. I hope to be able to report about our intrepid bloggers' reactions soon. In the meantime, thoughts and best wishes to all of them, be they out of isolation or still waiting for that first human contact to end the long winter.

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Antarctica - The Global Warning

Antarctica - The Global Warning, a award winning photographic book by Sebastian Copeland, is now available online. The website offers a short video tour of the book with an interview of the author, a photo-gallery, and images you can download for your own desktop.

Here are two of the images you can download:




The book itself, priced at $55.00 on Earth Aware Editions, will be available for purchase starting on September 17th.

Disclaimer: I have no direct or indirect connection with either Sebastian Copeland or Earth Aware Editions. I am plugging this book only because I think the photographs are great.

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Antarctic history revealed by shear wave splitting

Antarctica is a patchwork of different blocs, which have come together and split apart a number of times before forming the continent as we know it today. The history of this coming and going is written in the fabric of the Antarctic lithosphere, and can be read using standard seismological techniques.

One such technique is shear wave splitting, the investigation of shear wave birefringence through the upper mantle that has been rendered anisotropic by the accumulated effect of millions of years of tectonic processes. By measuring the anisotropy via shear wave splitting, we can attempt to unravel this tectonic history.

Bayer et al. (2007) present results of shear wave splitting measurements carried out on permanent and temporary seismic stations in Dronning Maud Land, Antarctica. They show that the anisotropy varies strongly with position, indicating the presence of distinct lithospheric blocs, separated by a suture that probably cuts through the whole lithosphere.

The anisotropy they find is not consistent with current plate motion, but in general follows the strike of magnetic anomalies, indicating that the crust and mantle were strongly coupled during the major tectonic episodes by which the Antarctic continent was assembled.

At near coastal stations this study agrees with previous research in finding evidence for two superposed layers of seismic anisotropy. The upper layer is consistent with local crustal magnetic anomalies. The lower layer is consistent with the first rifting stages of the Gondwana super-continent, when South Africa separated from the Antarctic continent.

In short, the seismic anisotropy found by shear wave splitting in Donning Maud Land strongly supports a succession of continental collisions, lithospheric extension and fragmentation. As the seismic experiments planned for the International Polar Year take place, there will be data from more locations in Antarctica, and more of the jigsaw puzzle of this frozen continent will fall into place.

References

Bayer, B., Muller, C., Eaton, D.W., Jokat, W. (2007). Seismic anisotropy beneath Dronning Maud Land, Antarctica, revealed by shear wave splitting. Geophysical Journal International, 171(1), 339-351. DOI: 10.1111/j.1365-246X.2007.03519.x

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Antarctic blog posts review #2

The topic for this week's Antarctic blog posts review is sun-up. Yep, the sun is now up at most Antarctic bases, really up, visible above the horizon and all...

Returning light
Light is indeed back at Scott Base, but the weather is not being cooperative. They have been hit recently by a spell of Condition 1 weather (i.e. storms that make it dangerous to be outdoors). Apparently, others have been hard hit by the storm too:

Up at McMurdo the blizzard scattered equipment, turned over vehicles and tore a chunk off the edge of one of the accommodation blocks.

Just a reminder that the environment can get harsh out there!

Sun up, getting plastered, Action Film Party
Julius over at Halley is back with a new post about the re-plastering of his broken leg (read about the breaking of said leg in my previous blog posts review), the return of the sun, and an action-film themed birthday party.

Julius seems fine after his leg-breaking adventure, and is working hard. Reading his post, I found out about the Halley sun-up ceremony, in which the youngest person on the base raises a new flag, which will stay up until it is shred to bits by the wind. I wonder what if any sun-up ceremonies are traditional at other bases...

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Sub-Antarctic 2006 : Photo Album

In March - April 2006, I went on a summer campaign to the Sub-Antarctic islands of Kerguelen, Crozet, St Paul and Amsterdam in the southern Indian Ocean. The following is a selection of the photo-album I made during the campaign.

This is an entirely personal view of the OP2006-1 which took me to the French Austral and Antarctic Territories. Many thanks to all those who made this trip possible, and to the travelling companions who made it so pleasant. Pascal, Michel, Lionel, Henri, Nicolas: you will find here a few of your photos to help me tell this story. Alessia

Marion Dufresne II

For a large part of the trip we were on board the Marion Dufresne II, a multi-functional scientific ship operated by the TAAF and by the Paul Emil Victor Institute (IPEV). The Marion was our floating home. A home with a view on the immensity of the ocean, which draws the eye to the distant horizon, and which is populated by strange creatures: black eyebrow albatross, flying fish, killer whales.




Crozet

Our first landfall was Possession Island, a land of wind and rain, where the vegetation clings close to the ground. The sky is the reign of the great albatross and the giant petrel; the waters are the reign of the royal penguin and the killer whale. I spent my only free afternoon at the royal penguin colony, surrounded by the stinking cacophony of many thousands of these strange but elegant creatures.





Kerguelen

An island of magnificent landscapes, Morbihan gulf, Ratmanhoff bay, Mount Ross, Greenland bay, Black Eyebrow canyon, Drumlins plateau and Studer valley, where I went hiking for two days. An island where the weather changes rapidly, where the games of light and shadow are continuous, and where the wind is king. The wind of Kerguelen knows no obstacles, it drives the rain, it stops the waterfalls, it grabs the waters of the rivers and the tiny humans that would cross them making them both fly, it is indisputably the absolute master of this land.







St Paul

A magnificent volcanic crater, a nature preservation, home to jumping penguins and fur seals. No penguins were visible because of the time of year, but there were many seals on the path up to the summit. The IPEV team: Roland, Henri and Nico.





Amsterdam

This is easily the most gentle island, with its moderate temperatures, its long grasses and its trees. One side of the island is a gentle slope marked by many small volcanic craters, with the Amsterdam gardens, the Phylica wood, BMG, Antonelli, Benedict point, the Virgin. The other side is dominated by a magnificent cliff, which has to be rappelled in order to arrive at Entrecasteaux. For fauna, watch out for the fur seals: they are everywhere!





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Overwintering in Antarctica - good for one's health?

It has always seemed to me that overwintering in Antarctica would be a fascinating experience, albeit not one I would engage in lightly if at all. I would not consider myself psychologically stable enough to endure the isolation. In any case, I would never have thought it could be beneficial to one's psychological health.

This article in Le Figaro online (which I only found thanks to a reference in a mountaineering blog of all places) refers to a recent article in The Lancet (Palinkas & Suedfeld, 2007) on the subject of the consequences of living for long periods of time in the polar regions.

It seems from this study, which includes amongst other measures of "health" the examination of diaries or logs written by the overwintering team themselves, that the physiological and psychological reactions to the environment are by no means only detrimental.

Of course there is an increased risk of accidents tied the the climactic conditions, and also some derailment of thyroid function and of the internal body clock. These last tend to cause perturbed sleep patterns, a loss of intellectual prowess and memory, and increased irritability that can lead to tensions and conflicts, all of which can cause depression.

However, the authors of the study underline that there are also positive side effects, notably the joy and self confidence that are a direct consequence of living in these difficult conditions and surmounting the difficulties as they come. The authors also found in the diaries many references to the beauty and grandeur of the environment, to the camaraderie and support of the entire team, and to the strong emotions generated by facing and surmounting the challenges the environment brings. It is also significant that many of those who overwinter once in Antarctica, apply to do so again.

All this rings true to me, although I have not, and probably never will, overwinter anywhere. Not only because I have been reading a number of web-logs of current and past overwinterers, but also because I have felt the same emotions myself, the same camaraderie, joy and self confidence, during summer campaigns in the sub-Antarctic. There is a saying in our group at the lab :

"The more difficult the campaign is, the better the memories when you surmount the difficulties, and the sooner you want to go back!."

References

L. Palinkas & P. Suedfeld, 2007. Psychological effects of polar expeditions, The Lancet, DOI:10.1016/S0140-6736(07)61056-3

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Featured earthquakes #3 : Peru

M8.0 Near the Coast of Central Peru.

This large earthquake occurred on Wednesday, August 15, 2007 at 23:40:56 UTC, at 30.2 km depth. It was 45 km (25 miles) WNW of Chincha Alta, Peru and 150 km (95 miles) SSE of LIMA, Peru.

At the time of this writing, the earthquake is known to have claimed some 330 lives, and have injured over 1300 people. You can read more up-to-date news agency reports about this earthquake: Reuters, BBC, CNN.


Here is the USGS ShakeMap for this event. It shows the intensity of shaking induced by the earthquake. It reaches very strong / severe level near the fault plane (which is shown by a black rectangle).
This earthquake occurred in a region known for its large magnitude events. The tectonic information that follows comes directly from the USGS web-page on this event.

The August 15 shock originated near the source of two earthquakes, both in the magnitude 8 range, that occurred in 1908 and 1974. This earthquake is south of the source of a magnitude 8.2 earthquake that occurred in northern Peru in 1966 and it is north of the magnitude 8.3 earthquake that occurred in 2001 near Arequipa, Peru.

The largest earthquake along the coast of Peru is the magnitude 9 that occurred in 1868. The 1868 earthquake produced a tsunami that killed several thousand people along the South American coast and also caused damage in Hawaii.

For those of you who like to look at seismograms, here are some of the records for this event taken from Rapid Earthquake View.



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Featured earthquakes #2 : Kerguelen

As promised in this post a while back, here is a short post about the M5.2 event that occurred on the island of Kerguelen at the end of July.

Kerguelen is a volcanic island in the Southern Pacific ocean. Its "known" seismicity is very low. However, as it is in a region with very few seismic stations, "low seismicity" may also mean low-level seismicity that is too small to be recorded on a sensible number of stations.

The M5.2 Kerguelen Island event was recorded on many seismographs of the global network, and is therefore reasonably well located. One of the stations that recorded the event is PAF (Port aux Francais) which is located on Kerguelen itself.

The PAF station also located several aftershocks. You can see the records for these aftershocks in the following images. The seismograms show vertical component of motion, high-pass filtered at 2 seconds.

The first figure shows the main-shock record in red, followed by the aftershocks recorded on the first day in black.

The second shows the main-shock again, followed by the aftershocks recorded on days 2 to 10 after the event.
Note how similar the aftershocks are to each other and to the main-shock.

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What am I reading?

They say one of the ways to understand how a person thinks is to discover what he or she finds interesting. In today's world, with RSS aggregators and the like, this has never been easier.

I have recently started using Google Reader to keep abreast with my online sources of information (other blogs, news websites, the latest contents of scientific journals). Google Reader allows me to easily share my favorite items, which means you yourself can keep up to date with what I find noteworthy and interesting, should you so desire.

You can find links to the latest items I've shared in Alessia's shared items, a panel on the right hand side of this blog (you may have to scroll down a little to reach it). You can read the full list on my shared items page. Or, if you're an RSS person yourself, you can subscribe to my shared items feed.

Some of the items I share will get blog posts written about them when I have time. Others will fall by the wayside. At least by sharing these items through Google Reader, I have some hope that not all that which piques my interest will fade and die...

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Shock Waves - the documentary

Shock Waves, is a 46-minute Emmy nominated documentary film, made to commemorate the centenary of the 1906 San Francisco earthquake. It is available to be viewed online on the USGS website (a decent internet connection is required).

The documentary includes historical footage, computer animations and interviews with earthquake scientists and engineers. It explains how the 1906 event spurred the birth of modern day seismology, and gives details on what we have learned since then, and what we hope to learn from current seismological experiments.

This is one of the best earthquake documentaries I have seen yet. It has received recognition as an outstanding documentary in the 2006 Telly awards.

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Posts on peer-reviewed research

Writing about peer reviewed research is something most reputable scientific bloggers engage in at some time or another. I feel it may be a good way to make rather technical scientific results more palatable to the interested layman, and put more of these results in the public domain.

Other advantages may be to bring more papers to the attention of over-worked colleagues, and provide the blogger with a platform to more or less systematically analyze and summarize the papers he or she is reading.

There is an interesting discussion on this subject at Cognitive Daily. The suggestion is to create a logo or badge that would signify "This post is about peer reviewed research", and also to set up a web-site which references all such peer-review posts. The objectives of this movement seem to be:

1. to create a consistent way to alert readers about the peer-reviewed nature of the subject being covered in the post they are reading;
2. to bring together in a single site references to all these posts;
3. give bloggers kudos for their commitment to high quality science posts.

Personally, I think a peer-reviewed research label is an excellent idea, and would be more than willing (time permitting of course) to write peer-review posts. Writing succinctly and clearly about other people's research will in any case be excellent practice for writing succinctly and clearly about my own!

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Concordia Science #2 - Glaciology

Concordia is not only a great site for Astronomy (see Concordia Science #1 - AstroConcordia), it is also an active site for Glaciology.

EPICA is the European Project for Ice Coring in Antarctica. Ice cores are used to obtain full documentation of the climatic and atmospheric record. This European funded project involved drilling and analyzing two ice cores and comparing these with their Greenland counterparts. One of the two sites chosen in Antarctica is Dome C, where the Concordia base is located. The other site is Kohnen Station, in Dronning Maud Land.

The Concordia ice-core, which was completed in December 2004, reached a depth of 3270.2 m, 5 m above bedrock and extended the record of climate variability to an age estimated to be around 890 000 years old. The ice-core results are being completed by studies on glacier flow, down-hole temperature and surface snow properties to refine climatic interpretations.

In a previous post I wrote about the sub-glacial lake under the Vostok station. There are many such lakes in Antarctica, a number of which are in the Dome C area near Concordia.


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Antarctic blog posts review #1

One of the best ways to learn about what life is like in Antarctica is to regularly browse blogs written by those who are currently out there. A number of these blogs are listed in the Antarctic Blogs of Note panel on my side-bar.

Some of the posts on these blogs are brilliant, and deserve to be shared. I have done so in the past by short posts of my own (see Midwinter: a great post from Halley, and McMurdo Blue Moon Run).

I would now like to try out a new format: a semi-regular blog post review, in which you will find short summaries of and links to recent Antarctic Blog posts that have interested me the most. So here goes:

The returning sun (when exactly is it going to happen?). I break my leg.
Julius over at Halley writes about waiting for the sun to re-appear (apparently it should rise for the first time on August 11th) :

I know from last year that as soon as the sun reappears you wish that it would go away because it is so bright that you have to immediately wear sunglasses.

Julius then goes on to recount his latest kiting escapade (kiting = skiing or snowboarding while being pulled along/up by a large kite), in which by a stroke of bad luck he ends up breaking his leg: Julius's leg is now in plaster, courtesy of Richard the Halley doctor, and he will now have to take it easy for a while. Amazingly, he seems pretty upbeat about it all:

Its not the greatest of things but it happens. I should hopefully have more time on my hands to keep you updated.

Best wishes Julius, and get better soon!


Et lux in tenebris lucet
Z-Doc, again over at Halley, has written a great post with many fantastic pictures of the return of sunlight at the base. Each picture has a detailed and informative description. Here is an example:

The winds settled and the thick layer of low cloud peeled back to reveal the beautiful 'mackerel skin' rippled appearance of altocumulus that makes the most beautiful skies; with it came light that has been so lacking for the last few months.

The post covers the arrival of light in the darkness (as by its title), but also kite-skiing and the daily task of launching of meteorological balloons, all illustrated by top-notch photographs. Well worth a read.


Celebrating the new bar
Phil, over at Scott Base, has written about the inauguration of their new bar, which is the social center of the whole base:

The refurbishment of the bar and lounge, which could be considered the centre of the base has been well worth the wait.

Worth a read for the pictures of the bar itself: what luxury! I wish we had something similar at our lab...


That all for this edition of the review. If you know of any posts or other Antarctic blogs that you think I should take a look at, please let me know.

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Erratum

The radio interview with the Concordia crew will be held on Sunday August 12th at 9 am CET on Rai Radio2, not on Saturday August 11th as previously announced.
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Concordia Interviews

If you'd like to hear more from the winter-over team at Concordia, here are some dates for your calendar:

Friday, August 10 : interview on France2 during the 8 pm edition of the news.

Saturday, August 11 : live interview with on Rai Radio 2 at 9 am CET. The program is called "Carpa Diem" (and not Carpe Diem for some reason), and the interview will be about the first dawn after 3 months of darkness.

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From Pietro Di Felice #2

Here is another post from our valiant man-at-Concordia Pietro di Felice. He has sent us some great photos, and expressed (in Italian) his delight that there are now fewer than 100 days before the first flight of the year reaches Concordia.

The longest night is over!

Jupiter seen through the telescopes at Concordia.

Cento, cento, cento ,cento !!!!!!!!!!!!!!!!!!!!!!!!!!!!!

No, no non sono diventato scemo tutto insieme, non vi preoccupate!!! Mancano 100 giorni all'arrivo del primo aeroplano, dell'arrivo di facce nuove e dell'inizio della campagna estiva.

I giorni corrono via uno dopo l'altro tra mille difficoltà ma anche ricchi di soddisfazione e di risate, giorni in cui avverti lo stress ed altri in cui regna la pace assoluta e la spensieratezza.

L'insalata è finita da 5 mesi, la frutta sta per finire (è tutta congelata s'intende) ed il latte pure (poi c'è rimasto quello in polvere) le patate sono finite ieri. In compenso abbiamo tanta cioccolata e dolci, biscotti e chi più ne ha più ne metta.

Uno dei vantaggi dello stare qui è che puoi mangiare le porcherie che di solito ti riempiono la faccia di brufoli e che fanno venire il culotto alle signorine, senza problemi poichè il metabolismo è talmente accelerato che l'organismo brucia tutto senza problemi, un pò come un camino (però attenzione ai fumi :-)))))))


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Science News: Antarctic microbes revived

Researchers from Rutgers University in New Jersey, US have managed to extract and grow bacteria from ice which was between three and five metres beneath the surface of debris covered glaciers in Antarctica.

The bacteria recovered and grew very quickly, according to the report. Those found in younger ice (100 000 years old) were more numerous and doubled in size faster than those found in older ice (several million years old).

One of the age-related factors that influence the revival rate of frozen bacteria seems to be the length of exposure to cosmic radiation. This damaging radiation, naturally stronger at the poles, causes DNA degradation, which increases rapidly for bacteria older than approximately one million years.

The full story from the BBC news website is available here: Ancient microbes 'revived' in lab

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Vacation is over

Hi folks,

vacation time is over, at least for me. I'm slowly getting back into the swing of things at the lab, and should soon be back to blogging regularly.

Some tidbits to be getting on with:

• the Times Online has an article comparing the recent Russian stunt of dropping a flag on the North Pole to the history of land claims in Antarctica before the Antarctic Treaty was established;
  
• Halley's Cometh has a great new post with stunning photographs of Antarctica at dawn, and a truly breathtaking video of an Antarctic storm;
• two moderate earthquakes have occurred near Antarctic and Sub-Antarctic stations managed by the observatory I work at (records to be posted soon): Magnitude 5.2 KERGUELEN ISLANDS REGION , July 28, 2007 ; Magnitude 5.9 - SOUTH OF AUSTRALIA , August 3, 2007 .
  

More coming soon!

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Geological Time-Scale

The above image is a geological time-scale. It gives the sequence of geological eras, with their corresponding ages. Note that not all of the ages are well known, although the order of the eras is.

Source: University of Calgary

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