Co- and post-seismic surface deformation and gravity changes of M_S7.0 Lushan, earthquake

On April 20, 2013, an earthquake with magnitude 7.0 occurred in the southwest of the Longmenshan fault system in and around Lushan County, Sichuan Province, China. This devastating earthquake killed hundreds of people, injured 10 thousand others, and collapsed countless buildings. In order to analyze the potential risk of this big earthquake, we calculate the co- and post-seismic surface deformation and gravity changes of this event. In this work, a multilayered crustal model is designed, and the elastic dislocation theory is utilized to calculate the co- and post-seismic deformations and gravity changes. During the process, a rupture model obtained by seismic waveform inversion (Liu et al. Sci China Earth Sci 56(7):1187–1192, 2013) is applied. The time-dependent relaxation results show that the influences on Lushan and its surrounding areas caused by the M_S7.0 Lushan earthquake will last as long as 10 years. The maximum horizontal displacement, vertical uplift, and settlement are about 5 cm, 21.24 cm, and 0.16 m, respectively; the maximal positive and negative values of gravity changes are 45 and -0.47 μGal, respectively. These results may be applied to evaluate the long-term potential risk caused by this earthquake and to provide necessary information for post-earthquake reconstruction.