Projet ANR-07-BLAN-0147 – CASE-IPY : Concordia Antarctic Seismic Experiment (International Polar Year)
Programme : Blanc (BLANC) 2007
Année de financement : 2007
Coordinateur du projet : CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE - DELEGATION REGIONALE ALSACE (CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE - DELEGATION REGIONALE ALSACE)
Partenaires : Centre national de la recherche scientifique; Institut de physique du globe; Université de Toulouse III - Paul Sabatier
Montant : 500000.0 euros
Date de début : 2008
Durée : 36 mois
Résumé : The Case-IPY project is a French contribution to the 2007-2009 International Polar Year (IPY) in seismology. The aim of IPY is to favour an intensive burst of internationally coordinated, interdisciplinary, scientific research and observations focused on the Earth's polar regions. Our project is part of a larger IPY initiative, the Polar Earth Observing Network (POLENET), which gathers 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. -  Seismological data from the POLENET observatories will provide the first relatively high-resolution data on the Earth beneath the polar seas and ice sheets. Advanced techniques to image the Earth's deep interior, such as seismic tomography, will be used to place constraints on the planets internal processes. Seismic imaging of the crust and mantle will assess causes for anomalously high ice elevations in East Antarctica, will provide information on heat flow and mantle viscosity that are key factors controlling ice sheet dynamics and the Earths response to ice mass change, and will provide constraints on the magma sources for polar volcanism. The axial vantage points of the poles will allow unprecedented studies of Earth's inner core, contributing to our understanding of the initial differentiation of Earth, of Earth's thermal history, and the physics and variability of the Earth's magnetic field. Enhanced seismic station coverage will vastly improve the detection level for earthquakes and permit evaluation of seismo-tectonic activity across the remote high latitudes. -  There are currently 9 permanent broad-band seismic stations and small aperture arrays located on the Antarctic continent, which report their data to IRIS (Incorporated Research Institutions for Seismology). Of these, only two closely spaced stations (SPA and QSPA at the South Pole) are located far away from the coast. Since 1998, EOST and INGV, in collaboration with the French and Italian polar agencies, have been running a project that aims to set up an experimental broad-band station at the French-Italian scientific base at Concordia, which is at 3250m elevation, ~1000 km inland from the coastal station Dumont d'Urville. The station has been recording continuously since December 2004 and has been a valuable test-bed for determining best practice in the installation of long running broad band seismic stations in the hostile conditions of the East Antarctic Plateau. -  We intend deploying 10 broad-band seismometers in East Antarctica, using Concordia / Dome C as our starting point. Our preferred location for these stations is between Concordia and AG01_camp (a temporary POLENET base). 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. 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, Chinese 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