Surface displacements associated with the L'Aquila Mw 6.3 earthquake (central Italy): New evidence from SBAS-DInSAR time series analysis

We investigate the surface displacements in the area affected by the April 2009 L'Aquila earthquake (Central Italy) through an advanced DInSAR analysis. In particular, we apply the SBAS approach to retrieve deformation maps and displacement time series from ENVISAT data acquired between February 2003 and October 2009 and COSMO-SkyMed data during the six-month interval following the earthquake. Our analysis shows no evidence of pre-seismic surface deformation at the 35-day temporal sampling of the ENVISAT sensor. On the other hand, by benefiting of the high spatial resolution and temporal sampling of the COSMO-SkyMed satellites, we measure post-seismic displacements at an unprecedented level of detail for a DInSAR analysis. This allows us to identify three main areas that continue to deform after the earthquake. In addition, our modeling shows that the post-seismic displacements are very likely related to the fault afterslip, since their decay times are on the order of 10^1-10^2 days.