基于断层面的天山地区潮汐应力触发地震研究  

Study on Earthquake Triggered by Tidal Stress Based on Fault Plane in Tianshan Region

作　　者：李金[1] 向元[1] 赵彬彬[1] 高荣[1] 

机构地区：[1]新疆维吾尔自治区地震局,新疆乌鲁木齐830011

出　　处：《地震研究》2016年第2期230-238,175,共9页Journal of Seismological Research

基　　金：新疆地震局基金(201304;201401);2015年度震情跟踪合同制定向工作任务(2015010301;2015010113)联合资助

摘　　要：选取2003～2014年天山地震带299个MS≥3.5地震的震源机制解资料,利用震中位置及其附近的断层信息来确定真实断层面。在此基础上分区域计算了整个天山地震带、天山中东段、南天山西段发震时刻断层面上潮汐正应力、潮汐剪应力、潮汐库仑破裂应力对天山地区地震活动的触发作用。在计算断层面上潮汐库仑破裂应力时,分破裂类型针对不同情况设定有效摩擦系数,讨论其对地震的触发作用。结果表明：天山地震带地震较多地发生于断层面上潮汐正应力的最小值附近以及潮汐剪应力的最大值附近。从潮汐库仑破裂应力结果来看,整个天山地区地震活动受潮汐阻滑作用较为显著;分区结果显示,天山中东段地区斜滑型地震、南天西段正断型地震受潮汐触发作用较为显著,其他各类型地震受潮汐阻滑作用较为显著或潮汐作用不明显。We chose the focal mechanism solutions of 299 M_S≥3. 5 earthquakes in Tianshan seismic belt during 2003 and 2014,and used the epicenter location of the selected earthquakes and the information of the fault nearby the epicenter to determine the real fault plane. On the basis of it,we calculated the trigger action of the tidal normal stress,tidal shear stress and tidal coulomb failure stress of fault plane on seismic activity in Tianshan area in origin time in each subarea which included the whole Tianshan seismic belt,the mid-east section of Tianshan seismic belt and the west section of southern Tianshan seismic belt. When we calculated the tidal coulomb failure stress on fault plane,we set the different effective friction coefficient of earthquakes in different fracture type and discussed the trigger action of tidal coulomb failure stress to the earthquake. The conclusion shows that earthquakes in Tianshan seismic belt occurred more frequently in the area near the minimum value of tidal normal stress and the maximum value of tidal shear stress on fault plane. From the result of tidal coulomb failure stress,the seismic activities were affected significantly by tidal resistance in the whole Tianshan region. The result of tidal coulomb failure stress in different subarea showed that the oblique-slip type earthquakes in mid-east section of Tianshan seismic belt and the normal fault type earthquakes in west section of southern Tianshan seismic belt were affected significantly by the tidal trigger action. The action of tidal resistance on other types of earthquakes was obvious or not obvious.

关 键 词：天山地震带 潮汐应力 潮汐触发 断层面 

分 类 号：P315.72[天文地球—地震学]