2011年1月安徽安庆M_S4.8地震震源区三维速度结构与发震构造讨论

Study on 3-D velocity structure around the focal region of the Anqing earthquake in January 2011 and its causative fault

摘要:

2011年1月19日安徽安庆发生MS4.8地震,本次地震发生在下扬子地块长江沿线前陆变形带。震后现场工作队调查汇总了建筑物破坏情况,计算得出较为精确的烈度分布。采用FOCMEC方法计算了主震震源机制解,并利用安徽地震台网对本次地震主余震的定位结果,结合地震层析成像技术对震源区地壳三维速度结构的成像结果进行分析,同时参考烈度分布的椭圆长轴优势方向,得出NE向的宿松-枞阳断裂可能是本次地震的发震断层的结论。

Abstract:

The Anqing MS4． 8 earthquake occurred on January 19，2011，and the epicenter lies in foreland deformation belt along the Yangtze River in Yangtze plate． After the earthquake，the field work team surveyed and summarized the building damage data，calculating intensity distribution， obtaining comparatively reliable intensity distribution graph． The focal mechanisms of main shock are calculated tentatively using digital seismic wave data in some provincial digital seismic networks based on the FOCMEC program，combing the first motion of P，SV and SH waves with their amplitude ratios． The comprehensive analysis of the major aftershock location result of Anhui seismic network，together with the focal region crust three-dimensional velocity structural images by the seismic tomographic technology，and the intensity distribution of elliptic long axis advantage direction reveals that NE trend Susong-Zongyang fault may be the causative fault of Anqing earthquake．