An integrated study on the coseismic and post-seismic deformation of the 2010 Yushu earthquake based on InSAR analysis

We carry out an integrated study on coseismic and post-seismic deformation caused by 2010 Yushu earthquake sequence, including both mainshock and aftershocks, by using multi-scene ENVISAT/ASAR data on two adjacent tracks. We map the extended deformation region to the west of mainshock and show the westward extension of seismogenic fault of mainshock. Based on our whole deformation field derived from mosaic interferograms, the total length of seismogenic fault reaches \({\sim }103\,\hbox {km}\) longer than \({\sim }71\,\hbox {km}\) suggested by the previous report. Several coseismic interferograms with different time baselines have similar deformation patterns, which indicate that the influence of aftershocks and post-seismic slip on coseismic deformation field is limited. Also, we observe a clear and separate deformation area, \({\sim }38\,\hbox {km}\) to the west of the mainshock epicentre, with maximum displacement of \({\sim }9\,\hbox {cm}\). The localised deformation is composed of two patches with opposite motion directions, where an aftershock cluster with at least 47 events (\({>}\hbox {Ms}\,3.0\)) occurred. We infer that this localised deformation is caused by aftershocks ruptured on a blind active fault. While a weak post-seismic deformation band along main rupture zone near mainshock epicentre is likely attributable to short-term afterslip.