A possibile breached relay ramp causing the 2013 Lunigiana earthquake (Northern Italy)

We applied the Differential Interferometric Synthetic Aperture Radar (DInSAR) technique to investigate and model the Mw 5.3 (Ml 5.2), June 21st, 2013 earthquake, occurred in the discontinuity zone between the Lunigiana and Garfagnana areas, NW Italy. We analyzed the coseismic displacement from two differential interferogram generated using COSMO-SkyMed X-band and RADARSAT2 C-band data. Both interferograms show a pattern of subsidence of a few cm located between the Lunigiana and Garfagnana basins. We then modeled the observed SAR deformation fields using the Okada analytical formulation and found them to be consistent with an extensional fault plane dipping towards NW at about 50°. Our results suggest that the fault responsible for the June 2013 earthquake may correspond to a breached relay ramp connecting the Lunigiana and Garfagnana seismogenic sources.