虑剪切力变化的速率-状态摩擦定律1-D地震过程数值模拟.docVIP

 考虑剪切力变化的速率-状态摩擦定律 1-D 地震过程数值模拟# 范清彪，许才军** 5 10 15 20 25 30 35 40 （武汉大学测绘学院，中国武汉，430079） 摘要：本文对考虑了剪切力变化的 Aging 速率状态摩擦定律的稳定性进行分析，推导得到了 新的临界等效弹性系数 kcrit???? (b?? a) / (1?? c)Dc 。基于该定律进行 1-D 地震过程数值模拟， 讨论分析了摩擦定律中各参数对地震周期、震后余滑时间、孕震成核时间及应力降（最大剪 应力与最小剪应力之差）的影响。并得出在滑动速率减弱区，当 a 与 b 非常接近（接近速率 中性区）或 D c 较大（断层非常粗糙或断层泥很厚，如俯冲带）时，震后余滑时间也会长达 数天甚至几个月，表明震后观测到的余滑也可能发生在速率减弱的孕震区，而不是以往所认 为的仅发生在速率增强区。对于由摩擦强度较大的辉长岩、花岗岩等结晶岩构成的断层，其 速率增强区的震后余滑不能用稳态滑动来表示。 关键词：固体地球物理学；速率状态摩擦定律；弹簧滑块系统；速率增强（减弱）；震后余 滑 中图分类号：P31 1D earthquake numerical simulation with rate-state friction law considering shear stress change Fan Qingbiao, Xu Caijun (School of Geodesy and Geomatics, Wuhan University, Wuhan, China) Abstract: The new critical stiffness kcrit???? (b?? a) / (1?? c)Dc is obtained based on the revised aging rate-state friction law which considering the change of shear stress. The effects of each parameter on the period of earthquake, the duration of afterslip and nucleation, the stress drop Δμ which is the difference between the maximum and minimum shear stress, are analysised through the 1D earthquake numerical simulation. In the velocity weakening zone, the time duration of afterslip may also would last for several days or even months if a is close to b ( velocity neutral zone ) or Dc is large which means the fault is very rough or with thick fault gouge like the subduction zone. This means that the observed afterslip can not only induced by the velocity-strengthening zone but also the weakening zone. The afterslip of the velocity strengthening zone is not steady state when the fault is composed of crystalline rocks , like gabbro or granite, which have high frictional strength. The afterslip of the velocity-strengthening zone is not steady state when the fault is composed of crystalline rocks , like gabbro or granite, which have high frictional strength. Key words: solid geophysics; rate-state friction law; spring slider system; velocity strengthening (weakening); afterslip 0 引言 基于摩擦实验，Dieterich[1]发