Imagerie sismique pour la prévention des risques sismique, volcanique

This work is methodological an experimental and focuses on the high resolution seismic imaging of complex structures associated to volcanic and seismic hazards. This work is closely related to the recent development of a new seismic-seismologic array (IHR). We focus on the high resolution seismic imaging of a strombolian type volcano located in central France. We account for the near-surface velocity variations and perform a 3D rst arrival time tomography using active sources. The results show two high velocity zones located at the bottom of the volcanic edice and interpreted as the volcano's feeder conduits. This work also focuses on the active faults seismic investigation. We study the potency of using fault-zone guided waves generated by active sources in order to characterize faultzone properties. We perform 3D full-waveform modelling using a spectral element method. We analyse the generation and propagation of synthetic fault-zone guided waves for a surface source. Our results prove useful for locating and imaging shallow fault zones.