Successful Concordia summer campaign

It has been over three months since I last posted here!! Field work simply got too exhausting for blogging, and since getting back from the field at the end of February, I've been running around trying to catch up with all the work that had been left behind.

Here is a short article (in French) we wrote for the IPEV website describing the deployment of the CASE-IPY Concordia-Vostok profile: Quatre nouvelles stations sismologiques au coeur de l'Antarctique

You can also download the Seismology at Concordia paper we wrote last year for the IPEV annual report.  The paper is in French, but it does have an English abstract:

Our understanding of earthquakes and the structure of the Earth derives from the analysis of ground motion recordings from a large number of networked seismic stations.  Mutual sharing of these records allows us to characterize earthquakes in detail, and also construct images of the interior of the Earth, called "tomographic images".  In order to obtain high quality images, seismic station coverage should be dense and homogeneous.  In the Southern hemisphere, the prevalence of oceans and the difficult access to land-masses lead to a deficit in coverage.  In the 1990s, there were only ten seismic stations in Antarctica, of which only one, South Pole, in the interior of the continent.  The "Seismology at Concordia" program aims primarily to establish a second "observatory-quality" continental station.  A second part of the project, present from the start and reinforced for the IPY, is the installation of autonomous stations for more local studies.

No fly ...

The weather is always sunny and bright at Concordia, absolutely perfect for flying... unless of course you're counting on it.

Today we are grounded by bad visibility. The original plan was for the Twin Otter to first take fuel to Vostok for us to use on the flight back from our farthest station, then on the way back here test-land at our five sites in order to determine the snow conditions. Unfortunately, the weather has taken a turn to the worse over the whole region, and there is not enough visibility to land anywhere except a well prepared and marked runway. The pilots have given us the "No Fly"...

The forecast - such as it is on the Antarctic plateau - is not good: the current cloud cover is predicted to remain for the next three days, which corresponds exactly to our flying window. We can only hope for the forecast to be inaccurate, and for a bright sunny day to appear before the end of the weekend, or all the CASE-IPY deployment may be delayed until our second flying window sometime after the January 22nd.

While waiting for the sun to appear again, we are going ahead with the second part of our summer campaign protocol: calibrating the two seismometers currently in the Concordia seismic vault, and installing a third instrument there. We have already measured and cut the length of signal cable required (70m), and are in the process figuring out the pinouts of the various connectors.

As Leonardo Di Caprio says in the film "Blood Diamond" : "TIA!", which I've reworded to "This Is Antarctica!", or as we say in France : "C'est l'Antarctique!"...

Ready to fly !

Above is a photo of one of our CASE-IPY seismic stations (excluding the solar panels) packed and ready to fly. In order to estimate the fuel needed to fly out to the sites we have picked, we were asked a few days ago to weigh a complete station and all the material required to install it. The total comes to 435 kg!! Of this, 70 kg is made up of spares (an extra seismometer and acquisition system) and tools. The remaining 365 kg is the station itself, including 10 big batteries to see us part of the way through the winter.

Ouch! ... to think we shall be manhandling all this over the snow in the middle of nowhere at the end of the week... we should probably take a sled with us to help lug the heavier items... a couple of weight lifters would be appreciated too, but probably wouldn't fit in the Twin Otter... pity!

Happy New Year !!

Happy New Year everyone !!

We've been busy people out here. First preparations for the New Year's feast, that ranged from lobster to snails to the traditional Italian "zampone e lenticchie". Then, on New Year's day, the arrival of the Raid, the convoy you can see in the photo above that comes 3 times every summer season to Concordia from Dumont d'Uvrille.

It takes the convoy 10 days to cover the 1100 km that separate us from the coast. It brings us most of the fuel, food, technical and scientific material needed to keep Concordia going for the whole year (a smaller amount of food and material comes in on semi-regular flights from either Dumont d'Urville or Mario Zucchelli bases).

As soon as the Raid arrives, Concordia transforms itself into a swarming ant-hill : its 80-odd ants (yes, this year we have reached a record : 84 people at Concordia!) unloading, transporting and reloading several tons of fuel and provisions... It would be utter chaos were it not almost second nature to the logistics people here, who keep the rest of us organized.

As I am hopeless at lifting and carrying stuff, I have posted myself in the kitchen for the past few days, in order to help our two overworked cooks, and one other volunteer, keep up with the extra "clients". Seriously tiring work, but the atmosphere is relaxed and enjoyable...

The CASE-IPY project is advancing well. We now have 4 out of 5 stations completely tested, and the first three stations are packed up and ready to fly. The indications we currently have say we should start flying on January 8th... fingers crossed!!

CASE station results : good data!

It has taken a while to get my head around the data we brought back from the three prototype CASZE-IPY stations, including the time we took off to celebrate Christmas, but I now have some preliminary results regarding data quality: it is excellent!!

The picture shows an earthquake that occurred last November 24th, in the Tonga region, recorded on the CAS03 station. CAS03 did not suffer from the field error that resulted in stopping the acquisition of data from the two other stations. It continued to record until June 3rd, a full month into the Antarctic winter. As soon as the sun showed itself above the horizon (August 16th) it started to come alive again, but did not have enough power to stay awake more than the few minutes of direct sunlight. Its first day of continuous recording after the winter was September 10th.

We are very happy with this result! In all, we recorded 42 separate earthquakes of magnitude 6.3 and above on the CASE stations last year. Not all recordings are of this quality, but all in all, I'm pretty satisfied with the result. Another source of satisfaction is that none of the GPS units failed this year, and the timestamps are accurate. This validates our choice of installing the GPS units directly inside the boxes housing the acquisition systems, and confirms that there is indeed enough signal quality through a wooden box cover and 20 cm of snow to get an accurate time.

Work is continuing on the CASE-IPY stations for this year's deployment. We plan to have everything completely tested by Wednesday. On Thursday, the big strong guys of the seismo team, together with several volunteers, will go back to the site of CAS02 to dig out the cable we were forced to leave there last time.

We still have no confirmed date for our five deployment flights in the direction of Vostok, but plan to be fully good to go by the end of next weekend...