A New Posthole Seismometer at Concordia Permanent Research Facility in the Heart of the Icy East Antarctic Plateau

• Published in: Seismological Research Letters
• Main Authors: Bès de Berc, Maxime, Zigone, Dimitri, Danecek, Peter, Steyer, Alain, Zanolin, Francesco, Maggi, Alessia, Thoré, Jean-Yves, Bernard, Armelle, Blumentritt, Hervé, Lambotte, Sophie, Lévêque, Jean-Jacques, Rivera, Luis, Alemany, Olivier, Possenti, Philippe, Vallée, Martin, Stutzmann, Eléonore, Cavaliere, Adriano, Cotte, Nathalie, Marino, Stefano, Gombert, Baptiste, Marie-Sainte, Wenceslas, Leroy, Nicolas, Pardo, Constanza, Pesqueira, Frédérick, Broucke, Céleste
• Other Authors: Institut Terre Environnement Strasbourg (ITES), École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Ecole et Observatoire des Sciences de la Terre (EOST), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Istituto Nazionale di Geofisica e Vulcanologia - Sezione di Roma (INGV), Istituto Nazionale di Geofisica e Vulcanologia, Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut des Sciences de la Terre (ISTerre), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Gustave Eiffel-Université Grenoble Alpes (UGA), L'Institut polaire français Paul-Emile Victor (IPEV), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2023
• Subjects: [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph]; Antarc*; Antarctic; Antarctica; South pole
• Online Access: https://hal.science/hal-04354829; https://doi.org/10.1785/0220230188

International audience Abstract In the Southern Hemisphere, the prevalence of oceans and the difficulty of access to land result in reduced coverage of seismological stations, limiting our detailed knowledge of Earth’s structures and of large earthquakes sources. This situation is exacerbated inside the antarctic continent, where only two permanent seismic stations are currently available (IU.QSPA at South Pole and G.CCD). The CCD station, built in early 2000s with state-of-the-art surface instrumentation and located at the French–Italian Concordia base (75° S, 123° E), has been providing seismological data since 2008. However, it suffers from several problems: the vault is deformed by the hydrostatic pressure of the snow, the firn waveguide traps anthropogenic noise from the base causing strong noise below 1 s, and a coupling defect limits the performance above 30 s on the horizontal channels. To ensure the continuity of CCD and to improve its overall performance, we started in 2014 to plan the installation of a borehole seismometer at the site. In this article, we describe in detail this renovation of CCD and some examples of data analysis. The new borehole sensor shows that short-period disturbances are largely attenuated (−20 dB at 0.1 s) compared to the surface installation and that the horizontal channels have a lower noise level at long periods (−8 dB at 100 s). Data for all components are below the standard noise model between 0.1 and 0.2 s, which makes this sensor one of the quietest installations in the world for this bandwidth. For periods >600 s we observe atmospheric pressure-related perturbations on the vertical component. Despite this problem, the new CCD borehole station is a success with better-than-expected performances at all periods <600 s. The data produced are now distributed in the world’s data centers as G.CCD.20 and we encourage the scientific community to use the data for all studies requiring seismograms from Antarctica.