Shallow subsurface imaging of the Piano di Pezza active normal fault (central Italy) using high-resolution refraction and electrical resistivity tomography coupled with time-domain electromagnetic data

Abstract

The Piano di Pezza fault (PPF) is the north-westernmost segment of the >20 km long Ovindoli-Pezza active normal fault-system (central Italy). Although existing paleoseismic data document high vertical Holocene slip rates (~1 mm/yr) and a remarkable seismogenic potential of this fault, its subsurface setting and Pleistocene cumulative displacement are still unknown. We investigated the shallow subsurface of a key section of the PPF using seismic and electrical resistivity tomography coupled with time-domain electromagnetic measurements (TDEM). We provide 2-D Vp and resistivity images showing details of the fault structure and the geometry of the shallow basin infill down to 35-40 m depth. We can estimate the dip and the Holocene vertical displacement of the master fault. TDEM measurements in the fault hangingwall indicate that the pre-Quaternary carbonate basement may be found at ~90-100 m depth.