2014年温州珊溪M4.2水库地震研究

A research on the 2014 Wenzhou M4.2 earthquake in the Shanxi Reservoir

2014年8～11月，浙江省地震台网及水库监测台网利用高密度、高分辨率监测台站完整记录到温州珊溪水库地震序列活动3000多次，最大震级为M4．2。本文从3D震中定位、震源机制解并结合库区地质构造特征等对此地震序列进行了探讨。HypoSAT地震定位法进行的定位结果线性拟合显示，主震发生在NW向断层，地震序列沿着活动断层密集成带，走向305°，倾向SW，倾角85°；采用P波初动符号方法得到了此次地震序列M3．5以上地震的平均震源机制解，节面B走向308°，倾角84°；野外地质调查研究表明，节面B的走向、倾角、倾向与双溪一焦溪断层产状基本一致；综合分析认为，NW向双溪一焦溪断层为此次地震的发震构造。

From August 2014 to November 2014, the Zhejiang Digital Seismic Network and reservoir monitoring network with high density, high resolution monitoring stations made complete records of Wenzhou Shanxi reservoir earthquake sequence of 3000 events with the maximum magnitude of M4.2. This paper discussed tectonic characteristics of the earthquake sequence in terms of the 3D epicenter location, focal mechanism solution and the geological characteristics in the reservoir area. The linear fitting of the HypoSAT positioning results a showed that the main shock occurred in the NW trending faults and the earthquake sequence along the active fault dense band has a strike of 305° with a SW tendency and 85° dip. By using P wave first motion focal mechanism of the earthquake symbols we obtain the average focal mechanism of M 〉 3.5 earthquakes. The nodal plane B has a .strike of 308° with an 84° dip. The field geological survey and research shows that the strike, dip and tendency of section B are consistent with the Shuangxi- Jiaoyang fault. The comprehensive analysis reveals that the Shuangxi-Jiaoyang fault in NW is the seismogenic structure of the earthquakes. Relationship between the earthquake and the earthquake fault and geological analysis in this paper results reflect the prediction has important theoretical value and practical significance in the study the earthquake seismogenic mechanism and future earthquake.