DInSAR Coseismic Deformation of the May 2011 Msubw/sub 5.1 Lorca Earthquake (southeastern Spain)

摘要

The coseismic superficial deformation at the region of Lorca (Murcia,southeastern Spain) due to the M_w 5.1 earthquake on 11 May 2011 wascharacterized by a multidisciplinary team, integrating information fromDInSAR, GPS and numerical modelling techniques.Despite the moderate magnitude of the event, quantitative information wasobtained from the interferometric study of a pair of TerraSAR-X images. TheDinSAR results defined the trace of the fault plane and evidenced uplift ofthe hanging wall block in agreement with the estimated deformation obtainedthrough an elastic rupture dislocation numerical model. Meanwhile for thefootwall block, interferometric results showed that tectonic deformation ismasked by an important subsidence related to groundwater extractionpreviously identified at the area of study.Horizontal crustal deformation rates and velocity vectors, obtained from GPSstations existent at the area, were also coherent with the tectonic settingof the southern margin of the Iberian Peninsula and with the focal mechanismcalculated for the Lorca event. The analysis of a continuous GPS site inLorca showed good agreement with the horizontal N–S direction componentrelative to the numerical model and tectonics of the region.This is the first time at this seismic active area that a multi-techniqueanalysis has been performed immediately after the occurrence of a seismic event,comparing the existing deformation data with a theoretical numerical modelbased on estimated seismic rupture dislocation.