Characterisation of a landslide fissure pattern by integrating seismic azimuth tomography and geotechnical testing

In order to characterise the fissure field provoked by the Super-Sauze mudslide (South French Alps) in the surface material, we conducted a seismic survey and compared the resulting P-wave tomogram to surface observations and cone penetrometer tests. The first results show that the distribution of the P-wave velocities correlates well with the fissure parameters, i.e. density, depth, and thickness, estimated from digital photographs and field observations. In addition, one finds good agreement between the P-wave velocity distribution and the material resistances interpolated from the penetrometer tests, indicating a probable physical relationship. The results of our study demonstrate that seismic azimuth tomography is efficient for characterising fissure systems with the main advantage of the method lying in the integration capacity of wave propagation compared to local mechanical tests. Provided that the correlation between P-wave velocity and fissure characteristics are confirmed at other sites, this technique could be the basis for future and more systematic studies of high-hazard zones related to landslides. Copyright (c) 2011 John Wiley & Sons, Ltd.