Coupling geophysical modelling and geodesy to unravel the physics of active faults

Abstract

The major requirements of seismic hazard assessment must address mainly the information about the expected location, time and magnitude of the impending strong earthquakes, as well as the scenarios ground motion associated with the possible future seismic events. While the quick notification of seismic events, appears nowadays pretty well established, thanks to the development of regional and local seismic networks, in terms of prevention more and more importance is devoted to studies of the inter-and pre-seismic earthquake cycle. To improve the intra seismic and pre-seismic information, which may lead to an effective mitigation of seismic risk, we are proposing an innovative approach, that combines Earth Observation data (GPS and SAR) and new advanced approaches in seismological and geophysical data analysis. The employed EO data are the observations acquired by means of SAR sensors, treated by Differential Interferometric techniques, the data observation acquired by permanent GPS stations or "ad-hoc" campaigns of the observations done over earthquake prone area. The aim is to combine the geophysical modelling of the faults with the surface displacement measured with the two mentioned techniques. In particular, application of the DInSAR techniques, using a stacking of interferograms, makes it possible, under the classical interferometric constraints (coherence, baseline, etc.), to retrieve a vertical displacements map, referred to a temporal interval, over areas where seismic fault system are localized. The displacements fields coming from GPS/DInSAR and other additional information, constitute the input for the geophysical model which shall indicate whether the fault is in a "critical situation".