Combining Seismic and CSAMT Methods in a Sinkhole Site Study

The Catalan Potasic Basin (Northeast of Spain) has been associated with subsidence and structural failures due to sinkholes influenced by salt mining activities. The study area contains three visible sinkholes developed in 60s, 2000 and 2002. Questions regarding the subsoil extension of the collapse/drainage zone and the mechanism of sinkhole formation are under study. Complex geology and presence of different materials susceptible to dissolution make difficult to understand the process based only on outcrop and borehole information. In this work, we present the combination of two geophysical techniques, seismic and Control Source Audiomagnetotelluric (CSAMT) methods, in order to delineate subsurface anomalies associated with the sinkhole formation. Combining both seismic velocity and resistivity models constrain the interpretation and helps to find high-porosity zones associated with sediment displacement and to define the evaporitic rock top.