Study of lithosphere structures and seismicity of Kerguelen
The main goal of the LISISKER (study of lithosphere structures and seismicity of Kerguelen) project is to characterize the structure and the deformation of the Kerguelen lithosphere through the use of seismological and geological data. The LISISKER project corresponds to a multidisciplinary approach and combines a set of various analysis and interpretation methods, in order to relate geophysical records (in particular from seismology), multiscale geological characterizations and geodynamic models. Large-scale structures of the lithosphere such as the Moho and the privileged areas of fluids and matter transfer over the Kerguelen plume are characterized using the seismic waves from distant earthquakes (study of SKS waves, receiver functions,..). The seismic recordings are interpreted by taking into account petrophysical characterizations carried out on xenoliths brought to the surface by the basaltic flows. These xenoliths, centimetric in size, represent pieces of the deep crust and the lithospheric mantle. Seismic properties of these samples are calculated taking into account petrological, geochemical and crystallographic fabrics characterizations.
The project also aims to characterize the deep dynamics of the lithosphere by locating the seismicity sources near the archipelago. With regard to the current seismic station coverage, the Kerguelen archipelago only currently benefits from the permanent station of the GEOSCOPE seismic network. Then, the deployment of several seismic stations operating on the Kerguelen area will locally improve the instrumental coverage and will complete the seismological network of the Indian Ocean.