日本9.0级地震后依舒断裂带北段地震活动性分析

结合测震学和大地测量学方法分析日本2011年9级地震之后依舒断裂带北段的地震活动性认为，2012年至今研究区地震活动相对平静是由于日本地震对区域应力场的影响。依舒断裂带北段震后1 a内受影响较大，2 a后地震活动减弱，b值的时间扫描表现出其目前处于低应力场控制。依舒断裂带北段2012年至今5 a未发生4级以上地震，当前存在发生4级地震的可能。

Seismic Activity Analysis of the Northern Segment of Yishu Fault Zone after M9.0 Earthquake in Japan

Using seismic and geodetic methods, we analyze the seismicity of the northern segment of the Yishu fault zone after the 2011 M9.0 magnitude earthquake in Japan. It is considered that the relative quiescence of seismicity in the region since 2012 is due to the fact that the M9.0 earthquake in Japan affected the regional stress field. The northern section of the Yishu fault zone is greatly affected within 1 year of the earthquake, and the seismicity declined after 2 years. A time scan of b values also shows that the northern segment of the Yishu fault zone is now under low stress field control. No earthquakes greater than magnitude 4 occurred in the northern section of the Yishu fracture zone since 2012, although there is a possibility of an earthquake of magnitude 4.