Conclusions

This study showed that a quadrangular seismic array could be used to explore the subsoil structure using seismic refraction and seismic interferometry methods. We apply these methods to obtain images of the velocity distribution (Vp and Vs) of materials prone to landslides. The refraction method can be used to determine the bedrock depth, which can also be inferred into the array by taking advantage of surface sources and receiver geometry. At the study site, the surface waves generated from an active source and extracted from the ambient noise allowed to delineate the extent of materials close to sliding, whose Vs values are less than 200 m/s and which notably contrast with the area of more compact materials.
 
At the moment, we find the best Vs velocities correlation obtained of both methods is observed on an average frequency of 24 Hz. Future research will analyze the differences due to the surface waves character and produce a 3D-Vs model. Finally, we can point out that in the case of a high risk of landslide, when it is not advisable to induce stress into the subsoil, ambient seismic noise can provide practical results to determine the extension of the sliding materials.