金寨震群震源深度确定及成因初步分析

摘要

金寨震群自2014年8月份开始活跃,随后发生多次有感中小震.震区群众反映对ML≥1.0地震均有感,并伴随有地声现象,可能是震源深度较浅的原因.本文主要利用sPL深度震相计算金寨震群地震的震源深度,共识别出16个地震的sPL震相,计算结果显示,这16个地震的震源深度分布在3.0～ 4.7km,比2014年4月20日霍山MS4.3、2011年6月7日桐城MS3.6地震的震源深度浅.同时利用hypoDD方法对该震群进行重定位,并在此基础上计算得到震群的扩展系数为0.27m2/s,这与前人对龙滩水库、小浪底水库诱发地震的计算结果接近.结合震群震源深度浅、扩展系数较小及时间丛集、空间紧密等特征对震群成因进行了初步分析,认为该震群可能由水库诱发.%The Jinzhai earthquake swarm began to be active since August 2014 and then a series of inductive small-medium earthquakes occurred.According to the descriptions by the local residents,the earthquakes with the magnitude greater than ML ≥ 1.0 can be clearly felt,accompanied by brontides.As a result,it's necessary to study the accurate focal depth of the swarm.Focal depth phase sPL is applied to calculate the focal depth of this swarm and the result shows that the focal depth of 16 events is within 5km,shallower than the Huoshan Ms4.3 earthquake which is in the same fault with the swarm and Tongcheng Ms3.6 earthquake.In addition,hypoDD method is used to relocate the swarm and then obtained the expansion coefficient on the basis of relocation result.The expansion coefficient is 0.27m2/s close to the results of Longtan and Xiaolangdi's.According to the characteristic of the Jinzhai earthquake swarm,a preliminary analysis of seismogenes was carried on and got a conclusion that the swarm may be related to the reservoir.