High-resolution imaging of the High Agri Valley Basin (Southern Italy) with electrical resistivity tomography

Abstract

The first high-resolution images of the fault-controlled High Agri Valley Basin obtained with the electrical resistivity tomography are presented. The Agri Valley is one of the more complex components of the Quaternary fault network of the Apennine chain. The geometry of the pre-Quaternary bedrock, the location and dip of the master fault and the tectonic evolution of the basin are still a subject of debate. Therefore, deep electrical resistivity tomography integrated with stratigraphic analyses has been carried out to improve knowledge of the geological setting of the basin. The high-resolution electrical images allow us to reconstruct the complex geometry of the basin. The electrical imaging highlights the irregular shape of the basin, which is bordered by shallow faults and filled with Pleistocene alluvial deposits. In longitudinal cross-section, the basin appears as a mosaic of fault-bounded blocks forming three different depocenters separated by intrabasinal highs. In transverse cross-section, the basin is an irregular graben, locally asymmetric to the northeast, and with secondary grabens due to antithetic faults.