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References: ENV21-13

Themes: Geological Sciences, Earth, Universe

Thesis location: Seismic Risk Assessment Section (BERSSIN) - Fontenay-aux-Roses (92)

Start: October 2021

Skills required

Master's degree in Geosciences; field geology

Age limit: 26 years old unless otherwise stated.

Thesis subject

The proposed work will advance knowledge of the current tectonic activity of the Cevennes fault system by providing important data for the calculation of the associated seismic hazard. The challenge is first to characterize regional vertical motions (uplift/subsidence) and local tectonic movements (along faults) from the geomorphological signal in the zone that frames the Cevenol fault system of interest, at the height of the city of Montélimar. This will be determined by the analysis of high-resolution topography, field observations and the dating of superficial deposits. The second part consists in looking on the faults for traces of past earthquakes in the superficial geological formations, characterizing and dating them. This analysis will be carried out using geophysical and paleoseismological (trench) investigations in the field. All this work will bring new results, since this system has never been studied in an extensive way before, for the understanding of the deformation and geodynamic processes that are responsible for it, as well as for the calculation of the seismic hazard in the region. The thesis is part of a vast national program mobilizing academic and institutional teams following the Teil earthquake.