2014年四川康定双震震源的勒夫波分析

发布时间：2019-04-01 06:54

【摘要】：2014年11月22日在四川省康定县发生了MS6.3地震(M1),3天后几乎在同一地点又发生了MS5.8地震(M2),本文称其为"康定双震".首先,利用逆时成像技术对康定双震以及用作经验格林函数事件的一次ML4.8地震(G1)进行了重定位,并利用广义极性振幅技术反演了三次地震的震源机制;然后,借助于G1的记录,利用经验格林函数技术分别提取了M1和M2的勒夫波视震源时间函数,并利用视震源时间函数的方位依赖性分析了M1和M2的优势破裂方向;最后,利用视震源时间函数反演方法反演了M1和M2的震源破裂过程.重定位结果表明,G1与M1和M2震源位置比较接近,分别相距~40km和~50km.震源机制反演结果表明,G1与M1和M2具有类似的机制,均为陡倾角左旋走滑.视震源时间函数的方向性分析表明,M1的破裂优势方向为276°,而M2的破裂优势方向为336°.破裂过程反演结果表明,M1持续时间~11s,主要破裂区沿断层面朝北西以及浅表拓展,最大位错~0.52m;M2持续时间~7s,破裂区沿着断层面也朝北西以及浅部拓展,最大位错~0.33m.
[Abstract]:The MS6.3 earthquake (M1) occurred in Kangding County, Sichuan Province, on Nov.22, 2014, and another MS5.8 earthquake (M2) occurred at almost the same location three days later. This paper calls it "Kangding double earthquake". Firstly, the inverse time imaging technique is used to relocate the Kangding double earthquake and a ML4.8 earthquake (G1) used as an empirical Green's function event, and the focal mechanism of the three earthquakes is retrieved by using the generalized polar amplitude technique. Then, with the help of G1 records, the Lev wave apparent source time functions of M1 and M2 are extracted by using the empirical Green's function technique, and the dominant rupture directions of M1 and M2 are analyzed by using the azimuth dependence of the apparent source time functions. Finally, the source rupture process of M 1 and M 2 is inversed by using the inversion method of apparent source time function. The repositioning results show that G1 is close to M1 and M2, and the distance between G1 and M1 is ~ 40km and ~ 50km, respectively. The inversion results of focal mechanism show that G1 has a similar mechanism with M1 and M2, both of which are left-lateral strike-slip with steep dip angle. The directional analysis of the apparent source time function shows that the rupture dominant direction of M1 is 276 掳, while that of M2 is 336 掳. The inversion results of the fracture process show that the duration of M1 is ~ 11s, the main rupture zone extends northwestward and shallow along the fault plane, and the maximum dislocation is ~ 0.52m; The duration of M2 is ~ 7s, and the rupture zone also extends northwestward and shallow along the fault plane, with the maximum dislocation ~ 0.33m.
【作者单位】：中国地震局地球物理研究所;
【基金】：国家自然科学基金(41474046) 中国地震局地球物理研究所基本业务费(DQJB14B01)联合资助
【分类号】：P315.33

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