由M_L≥4.0地震震源机制解推断四川理县-黑水断裂构造特征  

Tectonic Characteristics of Lixian-Heishui Fault Inferred by the Focal Mechanism Solution of the Earthquakes with M_L≥4.0 in Sichuan

作　　者：彭利媚 魏娅玲[2] 

机构地区：[1]海南省地震局,海口572900 [2]四川省地震局,成都610041

出　　处：《华南地震》2016年第3期9-16,共8页South China Journal of Seismology

基　　金：中国地震局测震台网青年骨干培养专项(20140320)

摘　　要：基于四川台网宽频带数字地震波形资料和CAP波形反演方法,提取了四川理县-黑水地区2008年1月至2014年12月10个M_L≥4.0中等强度地震的震源机制解。结果显示:10个中等强度地震震源机制解节面分布主要集中在北西-南东和北东-南西两个优势分布方向。据众多学者研究结果推断,北西-南东向展布的节面为发震断层面;理县-黑水断裂大致沿北47°西(近北西向)展布,属高倾角陡峭断裂,主倾向南西;压应力(P轴)呈近东西水平挤压特征,与断层面斜交,以左旋走滑运动为主;张应力(T轴)呈近南北水平撕裂特征;中等强度地震的震源主压应力方向与青藏地块东部地区主压应变率方向比较一致,说明理县-黑水断裂主要是受区域应力场控制的一个区域性构造左旋走滑断裂。Based on broadband digital seismic waveform recorded by Sichuan earthquake network and CAP waveform inversion method, the paper obtained the focal mechanism solutions of the ten moderately strong earthquakes with ML≥4.0 from January 2008 to December 2014 in region of sichuan Lixian-Heishui. The results show that： the nodal plane of the focal mechanism solutions of ten moderately strong earthquakes mainly concentrated in two dominance distribution directions（NW-SE and NE-SW）, and according to many scholars＇ research results inference, NW-SE trending section is earthquake fault plane; Lixian-Heishui fault is mainly distributed along N47° W（ near north west）, which belongs to high dip angle steep fault with dipping to SW;compressive stress（P axis） presents nearly EW horizontal extrusion features, and inclines with fault plane with takeing the left lateral strike slip movement; tensile stress（ T axis） presents nearly NS horizontal tearing features. The orientation of principal compressive stress of moderately strong earthquakes is consistent with the orientation of the principal compressive strain rate of eastern part of the Qinghai-Tibet block, which indicates that Lixian-Heishui fault is mainly controlled by regional stress field and is left lateral strike slip fault.

关 键 词：发震断层 震源机制解 CAP方法 波形互相关系数 断层类型 

分 类 号：P315.33[天文地球—地震学]