Geodetic, geological and geophysical evidence of active tectonics in south-western Sicily and offshore

Abstract

Starting from the analysis of interferometric data, which reveal a differential ground motion on a SW-NE alignment between Campobello di Mazara and Castelvetrano (south-western Sicily), we analyzed the evidences of active tectonics in this frontal sector of the orogen. The alignment falls within the seismogenic zone where the 1968 Belice earthquake sequence occurred. Even though this is the strongest seismic event recorded in Western Sicily in historical times, focal solutions provide different hypothesis on trend and kinematics of possible faulting mechanism. The discovery of dislocated archaeological and recent markers within the seismogenic zone enabled us to provide, for the first time, the likely evidence of surface expression for recent coseismic-related deformation. The geological data were complemented by new marine geophysical and GPS surveys with the aim to verify a possible correspondence between geodetic and geological-morphological data. The results confirm that oblique thrusting and folding, in response to current NW-SE oriented compression, is still active and this aspect must be seriously analysed in the evaluation of the seismic hazard of this densely populated part of Sicily.