One year of blogging

Sismordia is one year old today. I shall mark the anniversary with a look back at my original hopes for the blog and how things have evolved over the past year.

In my very first post Starting out I wrote:

The Concordia Seismic Experiment - as we have lovingly named it - has gone from residing somewhere in my brain, to being present also in my gut. It's a daunting thing, especially for me, as this will be both my first complete seismic experiment, and my visit to Antarctica.

I've set up this blog partly in order to relieve some of the tension that's building up as we prepare to make this experiment a reality, but also to share the experience with as many people as possible. I hope to convince some of my colleagues working with me on the experiment to participate in writing the blog, and I hope to entice you all to read it and send in your comments.

So my stated goals were

1. to share the experience of working in Antarctica;
2. to elicit the participation of my colleagues;
3. to entice you all to read my blog and send in comments.
   

Of these three goals, the first was for me the most important one, and I believe I have reached it. Blogging from the field in Antarctica was a great experience, and led to me compiling a Blog book about the campaign. I consider this document my greatest single blogging achievement.

In the second goal, I failed most miserably: Sismordia is still essentially a one-woman blog. My colleague JJL provided much needed copy-editing of the posts I emailed in from Concordia, but declined to write for Sismordia himself. As for those colleagues that have participated in the Antarctic seismology project (and continue to participate, for the project will live a few years yet), my greatest thanks go to JY.

My third goal was to be read. I was skeptical at first about the interest that a blog such as Sismordia could elicit in the blogging world. The subject matter is somewhat arcane, I tend not to deal in political controversy, and have not spent much effort in publicizing the blog.

Looking back over the statistics of the past year from Google Analytics, my 170 blog posts have received just over 5000 visits from about 3700 unique visitors who viewed a total of over 8600 pages. The graph below shows the number of visits per week over the past year. The peak in December-January corresponds to my Concordia field trip, which seems to have been the most successful time for Sismordia.



A few months after I started the blog, I linked my RSS feed through Feedburner. The number of subscriptions to my feed has risen gradually over the past year, and is now oscillating around 40.



So what can be said to sum all this up? Well for starters, I am still blogging, so the experience cannot have been too traumatic! As for the numbers, they are not Earth shattering, but are respectable all the same. I think I shall give my self a pat on the back as I settle into my second year of blogging.

Sunday seismometer #1

When I first started this blog nearly a year ago, I ran a short miniseries on my favorite historical seismometers from those on display at the Strasbourg Seismology Museum. The original series petered out after on three posts on the Wiechert, Galitzin and Ewing-Press instruments.

I am starting up the series again as a weekly feature (the Sunday seismometer) that will run over the summer months. I hope you enjoy it!

Reuber-Paschwitz (1889)

The seismogram above represents the first recording of a distant earthquake. It was made on April 17th 1889, in Potsdam, Germany, of an earthquake that occurred in Japan.

The instrument that made this first historical recording was built by Ernst von Reuber-Pashwitz.

Three years later, an identical instrument installed in the Astronomical Observatory in Strasbourg recorded another distant earthquake that occurred in Baloutchistan (a region that is shared by modern day Iran, Afganistan and Pakistan).

These two recordings mark the beginning of modern seismology.

The Reuber-Paschwitz was small (about 40cm in diameter) with a single horizontal pendulum. It seems that none of the original instruments have survived. We do, however, have a schematic drawing that you can see below.

Many of the physical characteristics of this seismometer are recognizable to modern-day seismologists: the horizontal pendulum, the three adjustable feet for leveling, the glass dome for protection from atmospheric perturbations.



The Baloutchistan seismogram recorded at Strasbourg:

Cool observations of glacial earthquakes

Glacial earthquakes have been one of the hot topics in seismology over the past few years. As they slide past asperities in the bedrock, certain glaciers emit long period seismic waves that can be detected by relatively distant seismic stations. These slip events are what we call glacial earthquakes.

Wiens et al. (2008) have recently published in Nature a set of beautiful observations of this phenomenon. They have put together information from regional seismic observations and a local GPS survey to constrain the nucleation, slip velocity and duration of glacial earthquakes occurring on the Whillans ice-field in West Antarctica.


They find that glacial earthquakes occur on this glacier twice a day, and seem to be triggered by tides in the Ross Sea. When the ice starts moving, it generates a seismic signal. Some minutes later, a second signal is generated when the moving ice hits the side of the glacier, and a third signal is generated when the ice hits the grounding line and stops moving.



The timing of these signals and the horizontal velocities measured by a temporary GPS network installed on the glacier give information on the amount of ice that moves in each event. Wiens et al. have estimated the energy released by the glacial earthquake to be equivalent to a M7 earthquake, only spread over the 20 minutes it takes the ice to stop moving.

For more publicly acessible information, read the early releases from ScientificBlogging and ScienceNOW.

Wiens, D.A., Anandakrishnan, S., Winberry, J.P., King, M.A. (2008). Simultaneous teleseismic and geodetic observations of the stick-slip motion of an Antarctic ice stream. Nature, 453(7196), 770-774. DOI: 10.1038/nature06990

Concordia film available from CNRS

During the 2007-2008 summer campaign at Concordia, a team from CNRS-Images filmed a number of the experiments being carried out on the site in the fields of glaciology, astronomy and seismology. The images have now been edited into a 34-minute documentary available directly from CNRS.

The seismology sequences were shot during the field installation of the CASE01 prototype station, and during our descent into the seismic vault (see the Seismology in the Freezer post). Watching the film made the whole experience come back to JY and me very vividly indeed.

The film is entirely in French (no dubbing or subtitles). Here is my translation of the film description:

The French-Italian station Concordia sits in the heart of the Antarctic plateau, on the site of Dome C, and at an altitude of 3233 meters of which more than 3200 meters are made of ice. It is a unique place, totally devoted to sciences. The 3270 meter ice-core project Epica permitted the decryption of up to 800 000 years of past climate. Other activities are in development at the site. The CNRS-Images team has followed the astronomers and the seismologists during their labors. At the start of February, the doors of Concordia will close to the summer technicians and researchers. Only 13 over-winterers will remain, both French and Italian. They will be there almost 10 months, far from everything, out of time, in this world of extremes.

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Keep up to date with the latest developments at http://sismordia.blogspot.com

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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Keep up to date with the latest developments at http://sismordia.blogspot.com