Characterization of the Avignonet landslide (French Alps) using seismic techniques
Résumé
The large Avignonet landslide (40 106 m3) is located in the Trieves area (French Alps) which is covered by a thick layer of glacio-lacustrine clay. The slide is moving slowly at a rate varying from 1 cm/year near the upper scarp to over 13 cm/year at the toe. A preliminary geophysical campaign was performed in order to test the sensitivity of geophysical parameters to the gravitational deformation. In the saturated clays where the landslide occurs, the electrical resistivity and P-wave velocity are little affected by the slide. On the contrary, S-wave velocity (Vs) values in the first ten meters were found to be inversely correlated with the measured displacement rates along the slope. These results highlight the interest of measuring Vs values in the field for characterising slides in saturated clays and of developing techniques allowing the 2D and 3D imaging of slides.