f Geophysical reconnaissance methods for landslides in softrocks - recent developments

In the past, ground geophysics, cf. MCGUEFFEY et al. (1996) and helicopter-borne systems, SEIBERL et al. (1995), had been successfully applied for reconnaissance work over landslide. Three geotechnical aspects are necessary for the civil engineer to evaluate the stability of landslides in unconsolidated sediments, the (i) 3-D shape with references to shear- and slip surfaces, the (ii) hydrogeological regime and its network within the slip mass, and the (iii) detection of movements and their directional tracking, cf. MCCANN & FORSTER (1990). By conducting typical near surface geophysics, e.g. electromagnetics, DC multi-electrode soundings, induced polarization, GEORADAR, or shallow seismics, sufficient information may be provided for the working geotechnician to proceed with the layout of drilling patterns, to locate trial pits and, and to (re)-design drainage systems.