Viscoelastic behavior of the crust around the Longmenshan Thrust Belt inferred from post-seismic deformation of the 2013 Lushan earthquake, China

Seven continuous GPS stations are located on the hanging wall of the Longmenshan Thrust Belt, and post-seismic deformation data of the 2013 Lushan earthquake have been recorded for nearly four years following the earthquake. We transform the data from a global reference frame to the South China Block reference frame, and then, the secular motion and post-seismic deformation of the Wenchuan earthquake are excluded using an exponential fit model. Based on our results, the viscosities of the low velocity zone at a depth of similar to 25 km and of the middle and lower crust around the Longmenshan Thrust Belt are obtained as 2.75 x 10(17) Pa.s and 2.56 x 10(18) Pa.s, respectively. The post-seismic rebound, which was observed near the Lushan epicenter, may represent the occurrence of overslip during the earthquake. The more complex structural style may have produced weaker fault activity along the southern segment of the Longmenshan Thrust Belt than along its middle and northern segments.