【摘要】 2014年8月3日16时30分,云南省昭通市鲁甸县发生M6.5地震,宏观震中位于鲁甸县龙头山镇(27.1°N,103.3°E),深度约12km。发震断层为NW向包谷垴-小河断裂,是NE向昭通-鲁甸断裂系的NW向次级走滑断层。文中利用鲁甸地震50个强震台站观测记录与135个测震台站观测记录,分别进行峰值加速度计算和S波辐射图案匹配,对此次地震发震断层方向进行讨论。结果表明,"NW向"的断层方向更符合强震、测震仪器观测值,同时与地震灾害现场调查结果一致。更多还原

【Abstract】 Ludian M6. 5 earthquake on August 3,2014 occurred in Ludian country, Zhaotong City,Yunnan Province. The epicenter is located at longitude 103. 3°E and latitude 27. 1°N with focal depth of 12 km. Macro epicenter is located in Longtoushan Town,Ludian Country. The seismogenic fault is the NW-striking Baogunao-Xiaohe Fault,which is a second-order strike-slip fault of the NE-striking Zhaotong-Ludian Fault system. In this paper,we use observation records of 50 strong motion stations in the Ludian earthquake to calculate the distributions of peak ground acceleration and horizontal peak ground acceleration. According to the records,we find that the strong motion records decay slowly along the northwestern direction,thus we infer that the seismogenic fault is in NW direction.Meanwhile,the horizontal peak acceleration distribution map is similar with the synthetic threecomponent peak acceleration distribution map,which illustrates the horizontal component is the main part. Normalized S-wave radiation patterns are drawn using the observation records of 135 seismic stations. In contrast to single couple source radiation pattern,we infer that the seismogenic fault is in NW direction. The amplitude in the southeast direction is slightly larger than the amplitude in the northwest and the difference is not big,showing that the rupture trends slightly to the southeast. The above results show that,the conclusion of Ludian M6. 5 earthquake rupture along the northwest direction is in consistency with the observation results of the strong motion stations and the seismic stations. In addition,the distribution of earthquake disaster also supports this conclusion.更多还原