Based on GPS measurements of GEONET in Japan,we investigated the coseismic slip and postseismic relaxation of the 2011 M9.0 Tohoku-oki earthquake,and analyzed its influence on China mainland.The results indicate that the Tohoku-oki earthquake produced significant coseismic displacement in China mainland,especially in Northeast China,where the displacements are comparable or even higher than the annual tectonic motion.The observed displacements of 1 year following the Tohoku-oki earthquake can be generally modeled by creep on the fault plane.The post-seismic relaxation in 1 year following this big event releases the strain energy equivalent to an earthquake of M8.7,and mainly imposes influence in eastern China.Its produced displacements reach 30 ％ of the annual tectonic motion.Furthermore,we predict that the influence of the Tohoku-oki earthquake in China will shrink quickly in the next 2 years.The viscoelastic relaxation in the deep depth has a significant influence in a long-term and at a large spatial scale,and has an extension effect in the northeast part of China for 50～100 years.The Tohoku-oki earthquake broke the locked segment of hundreds of kilometers between Eurasian and Pacific plate,and unloaded the stress in China mainland that accumulated by tectonic loading.Therefore,seismic activity in China after the Tohoku-oki earthquake is lower comparing to the seismic level before the earthquake.
