Earthquake damages is caused by permanent surface deformation due to fault offset, as well as dynamic shaking due to seismic waves. The first BETTER challenge considered for the Geohazards domain (driven by ETH Zurich) investigates whether the relationship between these two physical processes may provide a better understanding of earthquake hazard. To this aim, complete and homogeneous catalogs are necessary. Dynamic data is constantly acquired by seismic stations installed at ground surface, and used to generate ShakeMaps after a seismic event. Surface deformation can be measured by different geodetic techniques (e.g., Differential SAR INterferometry (DInSAR). DInSAR has been confirmed as a reliable technique to map and characterize co-seismic deformation, based on data acquired from the ESA Envisat satellite for the period 2002-2010, during which many earthquakes occurred. However, DInSAR analyses were performed for specific cases, by relying on different software solutions, as well as different processing parameters. Thus, results are often not complete, not consistent or extremely heterogeneous.
Figure: (left) ShakeMap (USGS) and (right) co-seismic interferogram obtained by processing ESA Envisat data (ESA images archive)
In this challenge we will produce a homogeneous catalog of co-seismic deformation associated with earthquakes with >5 magnitude by relying on the ESA Envisat ASAR dataset. Specifically, we will perform a back analysis to investigate co-seismic deformation taking advantage of the large amount of EO data available. We expect to derive empirical relationships or descriptors between earthquake physical parameters (e.g., magnitude, depth, fault plane dimensions, rupture mechanism, etc.) and the co-seismic deformation observed at the surface (amplitude and extension). This challenge will provide useful results for the scientific community involved in the study of earthquake hazard.