Geophysical Modeling in Seismotectonic Analysis

The integration of surface geological investigations with geophysical techniques is useful to characterize systems of active faults, whose deep anatomy is often complex. Geophysical methods can yield important information on the underground geometry of rupture planes. We give an overview of how an integrated analysis of geo-structural, seismological and gravimetric data can allow the identification and geometrical description of faults with associated density contrast both at the surface and at depth. At the surface, we accomplish this task by a Multiscale Derivative Analysis (MDA) of the Bouguer anomaly map and by the integration of the MDA maps with the epicentral distribution and all the available geological information. The characterization of fault structures at depth is instead performed by the combination of the Depth from Extreme Points (DEXP) gravity imaging method with the hypocentral sections. Further structural insights can be derived by integrating the information from gravity data and active seismic experiments, with the latter filling possible gaps related to gravity data resolution. We applied our multi-parametric approaches to different seismically active regions, such as the areas of Paganica hit in 2009 and Amatrice-Visso-Norcia hit in 2016-2017 (Central Apennines), and the area of San Giuliano di Puglia (Southern Italy), struck by a moderate earthquake in October 2002.