松软覆盖层对隐伏断层带围陷波的影响研究  

EFFECT OF OVERBURDEN SOFT LAYER ON FAULT-ZONE TRAPPED SEISMIC WAVES

作　　者：李少华[1,2] 王彦宾[2] 

机构地区：[1]中国地震局兰州地震研究所,甘肃兰州730000 [2]北京大学地球与空间科学学院地球物理学系,北京100871

出　　处：《高原地震》2011年第2期13-17,共5页Plateau Earthquake Research

基　　金：中国地震局兰州地震研究所青年基金(2010268);国家自然科学基金(40874020)

摘　　要：利用二维非均匀介质地震波传播的伪谱和有限差分混合方法,通过数值计算,讨论了松软覆盖层对隐伏断层带围陷波特征的影响。在没有覆盖层的情况下,围陷波振幅和围岩上相比明显增加,持续时间变长。覆盖层造成围岩上地面运动振幅增大,围陷波的部分能量传播到覆盖层中,使得围陷波的能量变小。随着覆盖层厚度增加,围陷波的振幅越来越小,和围岩上的振幅越来越接近。在松软沉积层的地区开展隐伏断层带的围陷波观测,需要考虑覆盖层厚度的影响。We applied 2D Fourier pseudospectral and finite difference hybrid method for heterogeneous medium to simulate the propagation of fault trapped seismic waves, and discussed the effects of overburden soft layer on trapped seismic waves. We found that for a fault without overburden layer, the amplitudes of trapped waves have larger amplitude and longer duration compared with those on the surrounding bedrock. Presence of overburden soft layer enhances the amplitude on the surrounding bedrock. Some energy of the trapped waves propagates into the overburden layer and the energy of the trapped waves decreases. With the increasing of the thickness of overburden layer, amplitudes of the trapped waves decrease and become similar to those on the surrounding bedrock. The thickness of overburden soft layer is a key factor that should be considered when fault trapped seismic wave observation is carried out in areas with soft sedimentary layers.

关 键 词：断层带围陷波 隐伏断层 松软覆盖层 数值计算 

分 类 号：P315.2[天文地球—地震学]