2011年盈江M_s≥4.0地震序列震源机制解与发震构造研究

英文篇名：Focal Mechanism Solutions and Seismogenic Structures of Yingjiang M_s≥4.0 Earthquake Sequences in 2011
中文刊名：地震研究
英文刊名：Journal of Seismological Research
作者：赵小艳 ; 韩立波 ; 龙锋
英文作者：ZHAO Xiao-yan1 ; HAN Li-bo2 ; LONG Feng3(1.Earthquake Administration of Yunnan Province ; Kunming 650024 ; Yunnan ; China)(2.Institute of Geophysics ; CEA ; Beijing 100081 ; China)(3.Earthquake Administration of Sichuan Province ; Chengdu 610041 ; Sichuan ; China)
中文关键词：CAP方法 ; 震源机制解 ; 盈江地震 ; 发震断层
英文关键词：CAP method ; focal mechanism ; Yingjiang MS5.8 earthquake ; seismogenic fault
出版日期：2012-10-15
机构：云南省地震局;中国地震局地球物理研究所;四川省地震局;
年：2012
期：04
出版单位：地震研究

摘要

基于云南数字地震台网和腾冲火山台网宽频带波形记录,采用CAP方法反演了2011年盈江MS5.8地震序列主震及MS≥4.0前震、余震的震源机制解。结果显示:主震震源深度为9km,与该事件的定位结果相一致;震源机制解的节面之一走向248°,倾角77°,滑动角19°。结合余震、烈度分布以及震区的活动构造,判定该节面代表了主震的发震断层面,相应的发震断层应是震区附近的北东向大盈江断裂。主震主压力轴方位为20°,除MS4.7余震为正断型地震外,其他7次地震都为纯走滑型地震,都具有NNE-SSW向近水平的P轴,与该区历史地震震源机制主压应力优势方向一致。综合应力场及构造分析表明,盈江MS5.8地震的发震动力学环境是:受印度板块向欧亚板块北东向挤压和缅甸弧对保山—腾冲地块北东向俯冲的双重作用,保山—腾冲地块呈现北东向水平运动,导致的大盈江断裂带左旋走滑错动的结果。
Basing on the broadband waveforms recorded by Yunnan and Tengchong Volcanic Digital Seismic Networks,we inversed the focal mechanism solutions of the main shock of Yingjiang MS5.8 earthquake sequences and MS≥4.0 foreshocks and aftershocks in 2011 by using CAP method.The results showed that the focal depth of the main shock is 9 km,which was consistent with the location depth of Yingjiang MS5.8 earthquake.Combining with the distributions of aftershocks and intensity and the active geologic structures in seismic area,the nodal plane which had the strike of 248°,rake of 77° and dip of 19° was identified to be the seismogenic fault plane of the main shock,and its corresponding seismogenic fault was Dayingjiang Fault with northeast trending in seismic area.The direction of principal compressive stress axis of the main shock is 20°.The MS4.7 aftershock was normal-fault earthquake,the other 7 earthquakes was strike-slip earthquakes with nearly horizontal P-axis in NNE-SSW direction,which was consistent with principal compressive stress axis of the focal mechanism solutions in historical earthquakes.Combination with stress field and tectonic settings comprehensively,the seismogenic dynamic background of Yingjiang MS5.8 earthquake was under the double effects which were northeastward compression of India plate to Eurasia plate and northeastward subduction of Burma arc to Baoshan-Tengchong block.The Baoshan-Tengchong block moved horizontally along NE direction,which leaded to the left-lateral strike-slip motion of Dayingjiang Fault

引文

陈培善,陈海通.1992.由环境应力值寻找地震危险区的尝试[J].地震地磁理测与研究,13(6):1-11.
    陈天长,堀内茂木,郑斯华.2001.利用P波初动和短周期P、S波振幅测定川滇地区地震震源机制解和应力场[J].地震学报,3(4):436-440.
    陈颙.1978.用震源机制一致性作为描述地震活动性的新参数[J].地球物理学报,21(2):140-159.
    刁桂苓,赵英萍.2004.大同晚期强余震前震源机制解的一致性特征[J].内陆地震,18(3):202-206.
    房立华,吴建平,张天中,等.2011.2011年云南盈江MS5.8地震及其余震序列重定位[J].地震学报,33(2):262-267.
    胡鸿翔,陆涵行,王椿镛,等.1986.滇西地区地壳结构的爆破地震研究[J].地球物理学报,29(2):133-144.
    季建清,钟大赉,张连生.2000.滇西南新生代走滑断裂运动学、年代学、及对青藏高原东南部块体运动的意义[J].地质科学,35(3):336～349.
    龙锋,张永久,闻学泽,等.2010.2008年8月30日攀枝花—会理6.1级地震序列ML≥4.0事件的震源机制解[J].地球物理学报,53(12):1-9.
    楼海,王椿镛,皇甫岗,等.2002.云南腾冲火山区上部地壳三维地震速度层析成像[J].地震学报,24(3):243-251.
    罗艳,倪四道,曾祥方,等.2010.汶川地震余震区东北端一个余震序列的地震学研究[J].中国科学(D辑:地球科学),40(6):677-687.
    马文涛,徐锡伟,曹忠权,等.2008.震源机制解分类与川滇及邻近地区最新变形特征[J].地震地质,30(4):926-934.
    倪四道,王伟涛,李丽.2010.2010年4月14日玉树地震:一个有前震的破坏性地震[J].中国科学(D辑:地球科学),40(5):535-537.
    韦生吉,倪四道,崇加军,等.2009.2003年8月16日赤峰地震:一个可能发生在下地壳的地震?[J].地球物理学报,52(1):111-119.
    吴建平,明跃红,王椿镛.2001.云南数字地震台站下方的S波速度结构研究[J].地球物理学报,44(2):228-237.
    泽仁志玛,刁桂苓,李志雄,等.2010.大震前显示的地震震源机制趋于一致的变化[J].地震,30(1):108-114.
    张中杰,白志明,王椿镛,等.2005.冈瓦纳型和扬子型地块地壳结构:以滇西孟连—马龙宽角反射剖面为例[J].中国科学(D辑:地球科学),35(5):387-392.
    郑勇,马宏生,吕坚,等.2009.汶川地震强余震(MS≥5.6)的震源机制解及其与发震构造的关系[J].中国科学(D辑:地球科学),39(4):413-426.
    钟继茂,程万正.2006.由多个地震震源机制解求川滇地区平均应力场方向[J].地震学报,28(4):337-346.
    Chen Y T,Zbou J Y,Ni J C.1991.Inversion of neaz-source broadband ac-ceferograms for the earthquake sourcetime function[J].Tectono-physics,197:89-98.
    Yao Z X,Harkrider D G.1983.A generalied reflection transmission coef-fient matrix and discrete wavenumber method for seisgrams[J].BSSA,73(6A):1685-1699.
    Zhao L S,Helmerger D V.1994.Source estimation from broadband dre-gionals seisgrams[J].BSSA,84(1):91-104.
    Zhu L P,Helmberger D V.1996.Advancement in source estimation tech-niques using broadband regional seismograms[J].BSSA.,86(5):1634-1641.
    Zhu L P,Rivera L A.2002.A note on the dynamic and static displace-ments from a point source in multi-layered media[J].Geophys JInt,148(3):619-627.