Source parameters of the 2008 Gerze Mw6.4 and Mw5.9 earthquakes from InSAR measurements

On 9 January 2008, an M(w)6.4 earthquake struck Gerze, Tibet of China, followed by 40 aftershocks with magnitudes equal to or greater than 3.5, including the biggest one with M(w)5.9 on 16 January 2008. Two tracks (1 ascending and 1 descending) of ENVISAT ASAR data were processed to precisely determine the locations and amplitudes of coseismic surface displacements firstly. Then the coseismic displacements were inverted to build uniform dislocation models and further distributed-slip models in in elastic half-space. The inverted results Suggest that the M(w)6.4 main shock is associated with a west-dipping fault plane with a strike of 218 degrees and a dip of 52 degrees, while the M(w)5.9 aftershock is related with a west-dipping fault plane, 3.2 kin west to the main fault, with a strike of 200 degrees and a dip of 59 degrees; and the peak slip of 1.9 m is located at a depth of 7.6 km in the main fault, whilst the maximum slip of 1.0 m is observed at a depth of 3.9 km in the aftershock fault plane.