1988年澜沧—耿马地震前震源区应力状态分析  

Analysis on Stress State in Seismogenic Area before Lancang-Gengma M7.6 and M7.2 Earthquakes in 1988

作　　者：易桂喜[1] 付虹[2] 王思维[1] 闻学泽[1] 龙锋[1] 

机构地区：[1]四川省地震局,四川成都610041 [2]云南省地震局,云南昆明650224

出　　处：《地震研究》2014年第3期332-338,489,共7页Journal of Seismological Research

基　　金：国家科技支撑计划(2012BAK19B01-01);中国地震局2014年度震情跟踪专项(M7)联合资助

摘　　要：利用1973年1月1日至1988年11月5日云南区域地震台网记录的地震资料,获得了1988年澜沧—耿马地震前震源及附近区域多个地震活动性参数的空间分布图像,初步揭示了震前震源区应力状态。结果表明:澜沧—耿马地震之前,研究区地震活动性参数分布具有显著的空间不均匀性特征。澜沧7.6级地震震源区以低于0.7的异常低b值、低a值以及整个研究区最短的局部复发间隔TL值为特征,表明震源所在断裂段在震前已处于高应力闭锁状态,具有发生大震的应力条件。Using the seismic data recorded by the Yunnan Regional Seismic Network from Jan.1,1973 to Nov.5,1988,we obtained the spatial distribution of several seismicity parameters （including the a and b values in the frequency-magnitude relationship,and the local recurrence intervals TL） in seismogenic and its surrounding area before Lancang-Gengma M7.6 and M7.2 earthquakes in 1988 to reveal the stress state in the seismogenic area before the earthquake.The main results show that the spatial distribution of seismic activity parameters was significantly heterogeneous in the study area before the Lancang-Gengma earthquake.The seismogenic area of the Lancang M7.6.earthquake had the characteristic of the abnormal low b-value that were much lower than the regional average （b ＜ 0.7）,low a-value,and the shortest recurrence intervals TL.All these implied that the fault where the focal located might have been locked under the high stress and more likely to generate major earthquakes.

关 键 词：澜沧—耿马地震 震源区 地震活动性参数 应力 

分 类 号：P317.727[天文地球—固体地球物理学]