EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Evolution of the Concordia seismological observatory station CCD (GEOSCOPE network): a new post-hole installation on Antarctica plateau

Dimitri Zigone1,2, Maxime Bes de Berc1, Peter Danecek3, Alain Steyer1, Francesco Zanolin3, Sophie Lambotte1,2, Olivier Alemany5, Philippe Possenti5, Adriano Cavaliere3, Stefano Marino3, Jean-Yves Thore2, Alessia Maggi1,2, Armelle Bernard2, Jean-Jacques Leveque1, Luis Rivera1,2, Martin Vallée4, Nicolas Leroy4, Eleonore Stutzmann4, Frédéric Pesqueira4, and Constanza Pardo4
Dimitri Zigone et al.
  • 1Université de Strasbourg/CNRS, Institut Terre et Environnement de Strasbourg, UMR7063, 67084 Strasbourg Cedex, France
  • 2Université de Strasbourg/CNRS, École et Observatoire des Science de la Terre, UAR830, 67084 Strasbourg Cedex, France
  • 3Istituto Nazionale di Geofisica e Vulcanologia, Centro Nazionale Terremoti, Via di Vigna Murata, 605, 00143 Rome, Italy
  • 4Université de Paris, Institut de physique du globe de Paris, CNRS, F-75005, Paris, France
  • 5Centre National de la Recherche Scientifique (CNRS), Institut de Géophysique de l’Environnement (IGE), Grenoble, France

In the Southern Hemisphere, the prevalence of the oceans and the difficulty of access to land result in a lack of coverage of seismological station which is a strong limitation Our knowledge of the Earth’s structures and of large earthquakes sources. This is particularly critical inside the Antarctic continent where only two permanent seismological stations are currently available (QSPA and CCD). Among them, the seismological station CCD is a joint program between EOST (Strasbourg) and INGV (Roma) and is installed at the Concordia scientific base (75°S 123°E). This observatory, built in 2000 with state-of-the-art surface instrumentation installed in a vault made of snow-covered containers, meets the required quality criteria and has been part of the GEOSCOPE network since 2008. However, it has become necessary to replace this installation for safety reasons, recurring snow coverage issues and seismological performances. The existing seismic vault is deformed by the hydrostatic pressure of the snow. Its proximity to the base causes strong daytime noise (~30 dB) at high frequencies (>1 Hz); the unconsolidated layer of snow about 100m thick forms a waveguide that traps anthropogenic noise from the base. In addition, a coupling defect of the instruments in contact with the snow limits the performance at low frequencies (< 0.03 Hz) on the horizontal channels.

Eight years ago, we proposed to install a borehole seismometer at a depth of 120m to limit the waveguide effects. A new shelter on stilt and the borehole drilling were carried out in 2018/2019. The installation of all the instrumentation has been completed by our team in January 2020. The analyses of the data show that the high-frequency disturbances are very largely attenuated (-30 dB at 10 Hz) compared to the surface installation and that the horizontal channels have a lower noise level at low frequencies (-20 dB at 0.01Hz). In addition, data for all components are below the standard noise model for frequencies between 5 and 9Hz, which already makes this new station one of the quietest installations in the world for those frequencies. A few problems remain to be solved, such as atmospheric pressure-related perturbations for periods longer than 600s on the vertical component. We are currently implementing several patches to try to better insulate the borehole. Updates will be presented during the meeting. Despite this problem at long period, the new CCD borehole stations is a success with better-than-expected performances at all periods shorter than 500s. The data produced are now distributed in the world data centers as G.CCD.20.

How to cite: Zigone, D., Bes de Berc, M., Danecek, P., Steyer, A., Zanolin, F., Lambotte, S., Alemany, O., Possenti, P., Cavaliere, A., Marino, S., Thore, J.-Y., Maggi, A., Bernard, A., Leveque, J.-J., Rivera, L., Vallée, M., Leroy, N., Stutzmann, E., Pesqueira, F., and Pardo, C.: Evolution of the Concordia seismological observatory station CCD (GEOSCOPE network): a new post-hole installation on Antarctica plateau, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-12520,, 2023.