Integrated geophysical investigations for seismic zoning in a coastal area of Northern Sicily

Abstract

The area, about 225 km2 large, ranging from the Eleuterio river to the S.<br />Leonardo river on the northern coast of Sicily, has suffered many earthquakes in<br />the past centuries and has for many years recognized as a seismic area. This paper<br />presents a set of integrated geophysical studies carried out in that area, including:<br />i) a statistical study of the past earthquakes in order to define the earthquake risk<br />(PGV or PGA risk), ii) a set of laboratory density measurements carried out on<br />samples of rocks (82 samples), Hi) a shallow refraction investigation (290 profiles)<br />in order to study the mechanical properties of such rocks, iv) a deep geoelectrical<br />investigation (200 VES) in order to reconstruct the main geological features with<br />particular regard to the geometrical distribution of the elastic and plastic<br />formations which have been piled up during the complex overthrusting of the<br />Sicilian chain, and v) a detailed study of the possible amplifications of the<br />groundmotions due to the geometry and the mechanical characteristics of the<br />shallow and intermediate rocks. The results, combined wih the knowledge of the<br />regional tectonic features and the locations of the involved seismogenetic volumes,<br />allow the formation of a picture of the seismic responses and the connected seismic<br />risk