Characterisation of a Landslide in Clay Deposits Using vs Measurements

We attempt to characterize the deformation generated by a large slide in clay formations by measuring shear wave velocity values in several zones with different slide velocities. Vs values at shallow depth were found to be inversely correlated with displacement rates measured by GPS, with a division by at least a factor of 2 between the zones unaffected and strongly deformed by the landslide. These results suggest that Vs mapping could provide valuable information on the deformation state of the clay at depth and that the evolution of Vs with time could be used as an indicator for characterizing the landslide activity.