发震时深浅构造相互作用导致横向断层致锁的有限元分析

本文利用三维有限元方法，研究和计算了大震发生前、发生时，发生后震源断层面与深部同面立接断层之间的相互作用以及发震后促使深部断层发生错动从而对震源区近场横向活动断层致锁的结果，得到以下结果：（１）临近大震前震源断层面端部调整单元下方的深部断层有较高的剪应力水平，造成震时对震源断层面发生底辟作用的条件，即调整单元区对应的深部断层单元首次满足破裂条件并发生破裂。（２）震源端部的调整单元和具有蠕能力的横向

THE FINITE ELEMENT ANALYSIS OF THE NEAR FIELD TRANSVERSE FAULT LOCKED ON ACCOUNT OF THE INTERACTION BETWEEN THE DEEP AND SHALLOW FAULTS DURING A STRONG EARTHQUAKE

By using 3-D finite element method,author studied and calculated the interaction between the source fault and the deep upright fault on the same plane before,during and after a strong earthquake and the near field transverse fault which is locked because of the dislocation of the deep upright fault. The following results are obtained:(1)Before a strong earthquake occurs,the deep fault units under the adjustment units have higher shear strain level with the result that the deep fault has a diapirism at the bottom of the seismic source fault during the earth-quake,namely,the deep fauIt units under the adjustment units first reach the fracture limit and split.(2)The adjustment units at the ends of earthquake source and transverse fault with the creeping capacity might prevent the earthquake faults from splitting.(3)A strong earthquake fault''s splitting spreads to transverse fault, which could not make the transverse fault locked but may make the deep fault splitting spread. The shallow transverse fault is twisted and locked when the deep fault''s splitting spreads to the bottom of the shallow transverse fault.Meanwhile,the seismometry quota concerned with the locked transverse fault appears, this quota is the very small earthquake belt which is controlled by the deep fault.(4)The resigning capacity of the adjustment units is limited during a strong earthquake,it may give rise to strong aftershocks the ends of the source fault.