Electrical resistivity tomography contribution to the characterization of underground cavities in the region of Safi, Morocco

Natural underground cavities represent a major risk that compromises the durability of infrastructures and buildings and requires an urgent evaluation in order to be integrated in urban planning and decision-making. Nevertheless, the assessment of the hazard related to them requires a better understanding of the complexity of karst phenomena that may be well-developed in an area even without the presence of any surface indices. Actually, evolutions of karst underground features are controlled by a set of predisposing factors. The present study aims to contribute to the delineation and characterization of underground cavities in the coastal part between Safi and Oualidia. The choice of the study area was based on a preliminary analysis of site conditions and the main controlling factors of superficial karst especially those related to geology, hydrology and geomorphology. In this part of Safi region, The high salinity of seawater enhances the process of dissolution creating so an aggressive environment and favorable conditions for an accelerated extension of karst networks. In order to detect and estimate the approximate extensions of karst networks and features in this area, results of seven electrical profiles were interpreted in correlation with available geological and hydrogeological information.