Summer is one week away

An odd title for the first week of December, maybe, but not a false one. In one week's time I start out for my third Antarctic summer campaign.

Destination: Concordia, via Paris, Hong Kong, Sydney, Hobart, and Casey.

We have great expectations for the campaign, including (finally!) the deployment of the CASE-IPY stations along a 700km long profile between Concordia and Vostok (the Russian base, next to the sub-glacial lake of the same name).

There will be much work to do during the next two and a half months, and many glorious sights. I shall do my best to keep you up to date, with stories and images from the field.

And now... back to my desk, for the campain preparation is far from over...

Location:Strasbourg,France

CASE-IPY wake-up poll

As you can see from the state of health information for the CASE-IPY stations, the last station to fall asleep for the winter was CASE03 on April 18th. Our group at the lab has opened a pseudo-spread-bet on its wake-up date (pseudo, as in no money changes hands).

You too can participate in the betting using this online poll. The poll is open starting today and will run until July 30th (so you have six weeks to vote). I shall publish the poll results sometime in August, and as soon as the stations actually wake up, we shall have our winners.

Best of luck to all those who decide to play!

Opinion Polls & Market Research

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Blogging hiatus is over

Apologies to my regular readers for the prolonged blogging hiatus. I have been somewhat absent from the whole blogging world for the past couple of months. It proved to be too difficult to blog from my last field-trip, and I have been working hard on a paper since getting back last month (the paper was submitted a few days ago, details soon).

In the meantime, a lot has been going on regarding CASE-IPY and other seismology at Concordia:

• The stations we installed during the last Antarctic field trip (CASE01, CASE02, CASE03) have now all gone to sleep for the duration of the Antarctic winter. The updated state of health plot for the stations shows that the longest running station CASE03 went into hibernation on April 18th. Bets are open as to when the first station will awaken in the spring.
• The permanent station CCD is running nicely, with both the heated and the unheated seismometers performing well. You can look up the state of health for the station, as well as journal plots for the data and snapshots of events (including the recent M7.9 Sichuan earthquake) on the Concordia Seismology website.
• We are planning both the 2008-2009 and the 2009-2010 summer campaigns at Concordia. The first campaign will be dedicated to recovering the full data from the CASE prototype stations, re-installing these prototypes for a second year of measurement, and upgrading the permanent station (CCD). We hope to stay longer than two weeks at Concordia this time, which should give us enough time to complete the essentials of the campaign and run a number of extra tests. The 2009-2010 campaign will be dedicated to installing 7 new autonomous seismic stations between Concordia and Vostok. Given the logistical constraints on the transport of all the material required for this deployment, we are building the stations this year. They will be shipped to Antarctica in the fall, will over-winter at Dumont d'Urville station, and will travel up to Concordia on the first land transport of the 2009-2010 season.
  

All in all, plenty to keep me busy and out of mischief! Now that my work load has simmered down to manageable proportions again (!), you can expect to see more of me in the blogging arena, and specifically many more Sismordia posts.


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Launching the Concordia Seismology website

One of the things that has kept me from blogging much lately has been writing and setting up a static website about Concordia seismology, giving access to public domain information about the permanent station CCD and the CASE-IPY experiment, including data snapshots.

The website is unimaginatively called Concordia Seismology, and can be found here: http://case.u-strasbg.fr.

It has dedicated CCD pages, dedicated CASE-IPY pages, and a list of conference (and at some point journal) publications concerning seismology at Concordia.

The Concordia Seismology website is not intended to be a static copy of this blog, rather a place to distribute technical information about the permanent and temporary stations at Concordia. It will act as the official online source of such information.

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CASE-IPY : daily data update

The images and pdf files available from this post are updated regularly.

We are very fortunate in being able to receive daily data updates from our prototype CASE-IPY stations. The following pdf files contain daily snapshots of the 1sps data (Z=vertical component, N=North-South component, E=East-West component):

CAS01.Z , CAS01.N , CAS01.E
CAS02.Z , CAS02.N , CAS02.E
CAS03.Z , CAS03.N , CAS03.E

The following image shows the vertical component seismograms of the latest available data for the three stations. Click on the image for a larger version.



Here is a quick description of the steps taken to process the data into these snapshots:

• three component analogue data is produced by a seismometer;
• the data is digitized by a Reftek-130 acquisition system and stored locally on flash cards;
• the Reftek turns on a radio modem once a day for 10 minutes;
• a PC at Concordia monitors the radio link to each station continuously, and launches the retrieval process for the previous day's data when the link is active;
• Jean-François Vanacker, who is wintering over at Concordia, checks the data have arrived correctly, compresses them and sends them to us via email once a day;
• my colleague JJL unpacks the data, views them, processes them into a more usable format (miniseed), places the raw and processed data in a central archive and updates the SOH (state-of-health) plot available from this post;
• I process the miniseed data to generate the daily snapshots, and update the pdf files available above.
  

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CASE-IPY : summary and preliminary results

The 2007-2008 summer campaign is now over, and it is time to take stock, analyze the preliminary data from the CASE-IPY experiment, and start planning next year's campaign.

The objective of the 2007-2008 summer campaign was to complete and deploy three prototype autonomous seismic stations around Concordia. The three stations have been deployed at the following coordinates, from which they transmit part of the data they record to Concordia via radio link:

CAS01 : S75° 08.0414' , E123° 16.0849'
CAS02 : S75° 03.8448' , E123° 14.7480'
CAS03 : S75° 06.8405' , E123° 28.5318

The preparation and installation of these stations would have been impossible without the logistical support provided by Concordia. The following people gave invaluable support to the project: Giuseppe De Rossi, Claire Le Calvez, Angelo Domesi, Shaun Deshommes, Fabio Piersigilli, Sandra Trifirò, Jean-François Vanacker.

You can find the available SOH (state of health) information for these three stations in this pdf file or in the following image. The symbols indicate the temperature and the input power voltage seen by the RefTek acquisition systems in each of the three stations. The horizontal axis represents time in days from January 1st.

All three stations seem to still be working one month after installation, although CAS03 seems to no longer be heated. Apparent data gaps in the first month are due to problems in the radio transmission rather than in the actual data acquisition.

Note: the SOH information will be updated regularly. Link to this post to keep up to date.

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Only 36 hours to go...

The third CASE station is now installed, albeit with a few minor adjustments to the mast caused by an incident involving our trench digging machine (see photo)... what can I say? These things happen in Antarctica! At least the GPS receiver on the top of the mast is still pointing up!

This morning we received news that our flight out of Concordia has been advanced. We leave the day after tomorrow, or in only 36 hours time! It is not unusual that scientific missions like ours get cut short for logistical reasons, but it is always a nuisance.

All in all, this has been a pretty successful mission. Three out of three CASE stations built and installed, and the permanent station put back on its feet. We would have liked to have achieved more, but so goes it.

Tomorrow's will be the last post from Concordia, this outpost in the middle of absolutely nowhere. I have grown quite fond of the place, despite the lack of oxygen, the bitter cold, and the necessary complications of living on an Antarctic base. I shall be sorry to leave.

[Photo credit : Angelo Domesi, who also took the photo on yesterday's post]

CASE-IPY : Second station installed

They have been a long time coming, but now the stations are dropping into place like clockwork. We installed the second one this afternoon, and it only took us three hours from start to finish. Yay!

Our six-person installation team seems to be working well. Not only are we getting the job done, we are also having fun doing it.

We're all a little tired (hence the shortness of this post), but very happy. Two down, one to go. If all goes as planned, the last station will be installed tomorrow afternoon.

CASE-IPY : First station installed !

It has taken us a lot of time and effort, but the first CASE-IPY station is finally installed. The photo above shows a snapshot of the station as we left it yesterday, and a subset of the installation team (from left to right: myself, Angelo and Claire - JY took the photo).

The seismometer is half a meter down, in between the two flagpoles at the right of the photo. You can see the the mast with the white radio antenna and black solar panels. You can no longer see the two large boxes either side of the mast, holding respectively the acquisition system and the batteries, because they are covered by snow. (If there is one thing that can be said about doing seismology in Antarctica, is that it involves a lot of shoveling snow!)

The funny looking vehicle on the left of the photo is the Flexmobile, with which the 5km journey to the station takes a little over half an hour. I was surprised how un-flat a snow plateau can be. The snow is hard in places and soft in others, making for a very bumpy ride, even in on caterpillar tracks.

Now the first station is installed, the others will follow quickly. The next two stations are scheduled for tomorrow and the day after. That will leave us with three days during which to monitor the stations before we fly back to Dumont d'Urville (our flight is on January 26th).

Time is short, but we are making the most of it...

Skidoo time

Today has been great!

We started off by deploying our first complete CASE-IPY station in a test location some 800m from Concordia. The idea was to identify problems with our setup and have time to correct them before our first real deployment next Thursday. We got everything done in record time (3 hours from start to finish) with no major glitches.

This is a test deployment, so we must go back to the installation site regularly over the next couple of days to check the power given by the solar panels and the temperature of our electronics. What a great excuse for skidoo rides!

Skidoos are the best form of short-distance transport out here. Unfortunately the base only has 4 of them for 60 people, and these are always breaking down. Most of the time we go around on foot.

I had never ridden a skidoo before today, nor a jetski or a motorbike, and was rather hesitant at first. However, one trip to our test station was enough to get me in the groove, as you can see by the photo above. I feel I shall be planning a number of such trips in the next few days...

The seismology tent

I apologize in advance for the shortness of this post. We have been getting all our equipment ready for tomorrow's full scale test installation, and I only have 5 more minutes before the last email connection of the day.

The photo above was taken inside the seismology tent yesterday morning. The stove had gone out overnight (probably due to the wind) and the temperature inside was -16C! Fun for working!

CASE-IPY : First week at Concordia

Apologies for the lateness of this post. Last night I was too tired to do much more than curl up and go to sleep. Looking over what we have done this past week, it is hardly surprising.

Apart from fixing the permanent station (see previous post), we have completed the setup of the first temporary CASE-IPY station and are now ready for a full-scale test deployment tomorrow (Monday).

Each station is physically composed of three large wooden boxes, containing respectively a seismometer, the acquisition electronics and a battery pack, a 7m mast, a radio antenna and three solar panels. All the boxes are conditioned with multiple layers of insulation to keep their contents as warm as possible. The radio antenna and the three solar panels are attached to the mast.

This past week we have prepared each of these elements so as to have as little fiddling with electrical connections as screws in the field as possible. The few connections that remain to be wired will not be a problem, especially after the experience of working at -59C in the vault earlier this week.

What you see above is the seismometer we will be using tomorrow. We have kept it under snow for the past few days, to get it used to the cold. Yesterday we took it out of its box for the first time and prepared it for use.

Playing in snow

Today we got our first real taste of the cold. So far we have been enjoying moderate summer temperatures of -30C, with little or no wind.

I was surprised at how comfortable such temperatures can be so long as one is sensibly covered up and there is no wind. This morning wind picked up, and though the temperature itself was still only in the low -30s, the wind chill made it seem more like -45C. We found that so long as one keeps moving and doing some form of physical activity, even this is not too bad.

One of the bits of work we had planned for today was learning how to install the 7m masts we will use for our radio transmission, GPS reception and to hang our solar panels on. Step one was making a hole in the snow, which involved considerable physical activity. Shovels? Yes, but for the most part we used a chainsaw and a pickax (see photograph - I am not in it, I was the one taking the picture). The idea is simple: use the chainsaw to cut the snow into blocks, use the pickax to loosen them, and the shovels (and one's hands) to get the blocks out of the hole. The method seems rather barbaric, but it works well, is very fast and is a lot of fun. Beats making snowmen any day!

Data acquisition for CASE (and html test)

This post has been re-edited to remove abortive formating from an emailed html post.

The picture above shows a RefTek-130 DAS (digital acquisition system) with all the cables and connections we will be using next month. Except that next month the DAS will not be on a table, with its companion electronics spaced out around it, but crammed in a box with 20cm of insulation on all sides.

The DAS is made by Refraction Technology who are based in Plano, Texas.

All the cables are specially made using silicone instead of ordinary cable covering material. At the temperatures we will be deploying our station at (-30 to -40C) only silicone cables will still be flexible enough to be installed without too much risk of them snapping.

During the winter months (May to October) the temperatures will descend to about -80C. At these temperatures even silicone cables will be stiff and brittle. This means there is no way of moving them without risking breakage, even if it were possible to visit the stations in the dark.

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Ice-raids, or how stuff gets to Concordia

This is a photo of the IPEV Raid, the ice-convoy that IPEV runs regularly between Dumont d'Urville and Concordia. The convoy takes approximately 10 days to cover the 1100 km that separate these two bases. It carries the hundreds of tons of material and fuel required to run Concordia, and the scientific experiments it supports.

Just over one ton the freight carried by the various Raids of this Antarctic summer is for CASE-IPY: seismometers, acquisition systems, radios, electronics, wooden boxes for station installation, solar panels, masts (for radio antennas and solar panels), and batteries.

The last of our equipment is now on our way to Dumont d'Urville on the second crossing of the Astrolabe (called R1 - counting starts at 0). It should then meet up with the second Raid (called Raid2 - counting starts at 1) at Dumont, and arrive at Concordia by the end of December, just in time for us to unpack it all and start working.

CASE-IPY @ AGU

For those of you not in the geophysics loop, AGU stands for the American Geophysical Union, and more specifically for the Fall Meeting of said union, which is held yearly in San Francisco. It is a gigantic meeting, bringing together between 10 and 12 thousand researches in all fields of geophysics.

I usually attend every year (I have missed only one in the past 8 years), but this year getting ready for Antarctica trumped over spending a week in San Francisco. Although I shall not be physically present, there will be some emanation of me in the form of a poster about the CASE-IPY experiment, and about seismology at Concordia in general.

Following are excepts from the poster, freely re-formated for online viewing. Also available are the official AGU abstract and the poster itself.

Scientific Objectives of CASE-IPY

The East Antarctica POLENET network of which the CASE-IPY deployment is a part (station map) will provide unprece dented coverage, allowing us to:

1. Improve our knowledge of regional crustal structure. Crustal thickness measurements will help trace the boundaries of the units that make up East Antarctica, enhancing our comprehension of the formation and breakup of Gondwana.
2. Improve our knowledge of regional lithospheric structure. The network will allow lateral variations in the structure of East Antarctica to be imaged at higher resolution than previously possible using both earthquake and ambient noise.
3. Improve our sampling for inner core studies. Analysis of inner core anisotropy and heterogeneity requires seismic paths nearly parallel to the Earth's rotation axis. The deployment of stations in Antarctica will dramatically increase the number of available paths.

Concordia Permanent Station

Concordia is the site of an experimental permanent seismic observatory station, which has been operational since 2005. The extreme temperatures present at the site (-60 degrees C) imply difficult operating conditions for the seismological equipment. The quality of the data we obtain from this station has been steadily improving as we resolve the technical issues related to working at such low temperatures.



2007-2008 Summer Campaign

This year we shall deploy three prototype stations within a 10 km radius of Concordia. Each station contains a broad-band seismometer, a data recorder, a radio transmitter, solar panels, batteries, heating elements and power control electronics. Each box is protected by 16-20 cm of insulation. Data is telemetered to Concordia once a day. At sundown, when the battry charge falls below a cut-off level, the stations will shut down; they will wake up in the spring, when the solar panels have re-charged the batteries.



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CASE-IPY - Scientific Project

CASE-IPY : Concordia Antarctic Seismic Experiment for the International Polar Year

The CASE-IPY project is a part of a larger IPY initiative, the Polar Earth Observing Network (POLENET), which includes contributions from 24 countries, including France, Italy, Australia and the United States.

The aim of the POLENET consortium is to investigate polar geodynamics, the earth’s magnetic field, crust, mantle and core structure and dynamics, and systems-scale interactions of the solid earth, the cryosphere, the oceans and the atmosphere. Activities will be focused on deployment of autonomous observatories at remote sites on the continents and offshore, coordinated with measurements made at permanent station observatories.

We propose deploying 10 broad-band seismometers in East Antarctica, using Concordia / Dome C as our starting point. Our deployment will be coordinated with those of our Italian, American and Australian colleagues in order to achieve maximum coverage of the East Antarctica Plateau, and to share a maximum of logistical support.


Proposed IPY deployments in East Antarctica. Red: CASE-IPY. Dark blue: USA. Dark green: Australia. Light green: Italy (INGV). Light blue (small symbols): TAMSEIS (previously deployed by USA).

Our deployment will cover a part of East Antarctica that has as yet never been the subject of investigation, and will be a fully functional seismic antenna in its own right. It will also complete and connect the American, Australian and Italian deployments, thereby helping to create a single, large-footprint seismic array which will cover a substantial portion of the continent.

This combined POLENET East Antarctica network will number some 55 stations, and will have a combined length of over 4000 km, with a significant 2D component, providing unprecedented coverage of East Antarctica, and allowing us to reach the following objectives:

1. improve our knowledge of the regional crustal structure;
2. improve our knowledge of the regional lithospheric structure;
3. improve our sampling for inner core studies.

You can read more about the project on the IPY Expression of Intent database, which you can reach from this post: Concordia Antarctic Seismic Experiment - International Polar Year.

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IPY news : CASE-IPY is selected !!!

Our International Polar Year project has just been selected by the ANR (Agence National de la Recherche)!! In short, this means the CASE-IPY project has passed scientific scrutiny, and is deemed worth of funding. Phew....!!!!

We have been waiting a long time for this news (ever since the application deadline, which was March 1st - four months ago). My first reaction upon hearing the news this morning was elation: "We made it!". The second was: "Oh my God we are actually going to have to run this crazy experiment..." Still, even that thought is no way near enough to wipe the grin off my face.

Now for the dampener: although the project selection phase is now over, we still do not know what the funding decision itself will be. The ANR conditions funding of selected projects on the validation of each project's budget, on their financial analysis of our partners, and on the transmission of all necessary administrative and financial information by each of the partners.

In short: today's news means we should be funded, but we don't yet know by how much.



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Concordia Antarctic Seismic Experiment (International Polar Year)

So what exactly are we hoping to do during the International Polar Year? The short answer is study Earth structure.

The exact details of what we will end up doing are as yet unknown, dependent as they are on funding results, logistic possibilities, and the whims of equipment and nature. However, we do know what it is we hope to achieve.

Most if not all the projects that have been proposed for the IPY are listed in an Expression of Intent (EoI) Database maintained on www.ipy.org. The following is an excerpt of the EoI for our seismic experiment project (links within the excerpts are to Wikipedia entries for technical terms). Interested readers can find the full EoI here.

Concordia Antarctic Seismic Experiment for the International Polar Year (CASE-IPY)

We propose deploying 10 broad-band seismometers in Antarctica, starting at the French-Italian scientific base at Concordia, and trending southwards. Our deployment will be coordinated with those of our Italian, American and Australian colleagues in order to achieve maximum coverage of the Antarctica Plateau and to share a maximum of logistical support. Our combined deployments will allow us to improve our knowledge of the crustal and lithospheric structure of Antarctica, as well as to provide data for core studies.