3D GPR imaging for paleoseismology in Central Appennines (Italy)

Abstract

The knowledge of spatial position and geologic characteristics of active faults is fundamental to locate these elements on geologic maps and better define the potential seismological hazard of an area. A Quaternary fault in the “Piano di Castelluccio” basin, in Central Italy, has been already studied through paleoseismological analysis, provided stratigraphic data on sedimentary units and highlighted evidences of “recent” faulting related to past strong earthquakes. This fault has been defined “silent”, because events were not included in the current seismic catalogues, retaining uncertainties in the definition of the seismic hazard of that area. 2D/3D GPR surveys were done to image the fault zone and to provide new complementary data on the shallow sediments. The 3D data provides continuity of information over the investigation site, characterizing the structure in a total non-invasive way, whilst long 2D profiles were used to extend the study on a wider area. Final images show a characteristic GPR signature of a tectonic structure and faulted units: data reveal its position and continuity in space and highlight clear geometric features, providing useful qualitative and quantitative complementary data.