2015年4月25日尼泊尔M_S8.1大地震的同震效应
详细信息 本馆镜像全文    |  推荐本文 | | 获取馆网全文
摘要
应用有限单元方法,计算了2015年尼泊尔MS8.1大地震发生产生的同震变形和应力变化.计算中考虑地球为球体以确保远场应力场变化得到可靠结果,采用PREM模型的地球分层模型,考虑了中国地震局(CEA)和美国地质调查局(USGS)各自提供的断层滑动模型.结果表明:尼泊尔MS8.1地震是一个比较典型的低角度逆冲地震,水平位移和应力降较大;地震造成南北方向上的水平位移最突出,且集中在首都加德满都附近区域.USGS断层滑动模型地表最大位移量达到3.5m,CEA滑动模型最大为1.2m;东西向和垂直方向上的同震位移相对较小;同震位移量级在0.1m的影响区域可达300km;地震造成尼泊尔地区最大库仑应力变化可达到MPa量级,地震危险性依然较大.此次MS8.1地震对我国西藏地区有一定影响,特别是雅鲁藏布江地区和拉萨块体南北走向的正断层,库仑应力变化为正,量级可达数千帕乃至十余千帕,应该注意该区被诱发中强震的可能性.
The co-seismic displacement and stress fields of MS8.1earthquake in Nepal were calculated using finite element method in this paper.Curvature of the Earth was included in our model to get accurate results in far field.We adopted the PREM earth model and two different slip models in the calculation.Nepal MS8.1earthquake is a typical low-angle thrust earthquake,co-deformation mainly concentrated in the horizontal plane.The co-seismic displacement is mainly in north-south direction and concentrated near Kathmandu.East-West and vertical components are relatively small.The USGS slip model gave a maximum displacement around 3.5 m,while the CEA slip model is up to 1.2 m.The range of influence is about 300 km within which coseismic displacement is over 0.1 m.Coulomb failure stress change caused by the earthquake is positive in the vicinity of Nepal and its maximum is about several MPa.The MS8.1earthquake could affect China′s Tibet region,especially in areas of the Brahmaputra and the Lhasa block,where Coulomb failure stress changes are positive and the magnitude is up to 10 kPa for N-S trending normal faults,which implies possibilities of triggering strong earthquakes.
引文
Amelung F,Wolf D.1994.Viscoelastic perturbations of the Earth:significance of the incremental gravitational force in models ofglacial isostasy.Geophys.J.Int.,117(3):864-879.
    Antonioli A,Piersanti A,Spada G.1998.Stress diffusion followinglarge strike-slip earthquakes:a comparison between sphericaland flat-earth models.Geophys.J.Int.,133(1):85-90.
    Ben-Menahem A,Singh S J.1968.Eigenvector expansions ofGreen′s dyads with applications to geophysical theory.Geophys.J.Int.,16(4):417-452.
    Ben-Menahem A,Singh S J,Solomon F.1969.Static deformationof a spherical earth model by internal dislocations.Bull.Seism.Soc.Am.,59(2):813-853.
    Ben-Menahem A,Israel M.1970.Effects of major seismic events onthe rotation of the Earth.Geophys.J.Int.,19(4):367-393.
    Chinnery M A.1961.The deformation of the ground around surfacefaults.Bull.Seism.Soc.Am.,51(3):355-372.
    Chinnery M A.1963.The stress changes that accompany strike-slipfaulting.Bull.Seism.Soc.Am.,53(5):921-932.
    Deng Q D,Cheng S P,Ma J,et al.2014.Seismic activities andearthquake potential in the Tibetan Plateau.Chinese J.Geophys.(in Chinese),57(7):2025-2042,doi:10.6038/cjg20140701.
    Fu G Y,Sun W K.2007.Effects of lateral inhomogeneity in aspherical Earth on gravity Earth tides.J.Geophys.Res.,112(B6):B06409.
    Fu G Y,Sun W K.2008.Surface coseismic gravity changes causedby dislocations in a 3-D heterogeneous earth.Geophys.J.Int.,172(2):479-503.
    Fu G Y,Sun W K,Fukuda Y,et al.2010.Coseismic displacementscaused by point dislocations in a three-dimensional heterogeneous,spherical earth model.Geophys.J.Int.,183(2):706-726.
    Hodges K V.2000.Tectonics of the Himalaya and southern Tibetfrom two perspectives.Geological Society of America Bulletin,112(3):324-350.
    Mittal H,Kumar A.2015.Stochastic finite-fault modeling of Mw5.4earthquake along Uttarakhand-Nepal border.Nat.Hazards,75(2):1145-1166.
    McGinley J R.1969.A comparison of observed permanent tilts andstrains due to earthquakes with those calculated fromdisplacement dislocations in elastic earth models[Ph.D.thesis].Pasadena,California:California Institute of Technology.
    Molnar P,Tapponnier P.1975.Cenozoic tectonics of Asia:effectsof a continental collision.Science,189(4201):419-462.
    Nostro C,Piersanti A,Andrea A,et al.1999.Spherical versus flatmodels of coseismic and postseismic deformations.J.Geophys.Res.,106(B6):13115-13134.
    Nostro C,Piersanti A,Cocco M.2001.Normal fault interactioncaused by coseismic and postseismic stress changes.J.Geophys.Res.,106(B9):19391-19410.
    Okada Y.1985.Surface deformation due to shear and tensile faultsin a half-space.Bull.Seism.Soc.Am.,75(4):1135-1154.
    Okubo S.1992.Gravity and potential changes due to shear andtensile faults in a half-space.J.Geophys.Res.,97(B5):7137-7144.
    Pollitz F F.1996.Coseismic deformation from earthquake faultingon a layered spherical Earth.Geophys.J.Int.,125(1):1-14.
    Prajapati S K,Kumar A,Chopra S,et al.2013.Intensity map ofMw6.9 2011Sikkim-Nepal border earthquake and its relationshipswith PGA:distance and magnitude.Nat.Hazards,69(3):1781-1801.
    Press,F.1965.Displacements,strains and tilts at teleseismicdistances.J.Geophys.Res.,70(10):2395-2412.
    Rudle J B.1982.Viscoelastic-gravitational deformation by arectangular thrust fault in a layered Earth.J.Geophys.Res.,87(B9):7787-7796.
    Sabadini R,Piersanti A,Spada G.1995.Toroidal/poloidal partitioning ofglobal post-seismic deformation.Geophys.Res.Lett.,22(8):985-988.
    Saito M.1974.Some problems of static deformation of the earth.J.Phys.Earth,22(1):123-140.
    Shah A A.2013.Two great historical earthquake ruptures revealedin Nepal.Current Science,104(8):994.
    Shi Y L,Cao J L.2010.Some aspects in static stress changecalculation———Case study on Wenchuan earthquake.ChineseJ.Geophys.(in Chinese),53(1):102-110,doi:10.3969/j.issn.0001-5733.2010.01.011.
    Shi Y L,Zhu S B.2006.Discussion on method of calculating strainwith GPS displacement data.Journal of Geodesy and Geodynamics(in Chinese),26(1):1-8.
    Steketee J A.1958.On Volterra's dislocations in a semi-infiniteelastic medium.Can.J.Phys.,36(2):192-205.
    Sun W.1992.Potential and gravity changes caused by dislocationsin spherically symmetric Earth models.Bull.Earthquake Res.Inst.Univ.Tokyo,67(2):89-238.
    Sun W K,Okubo S.2002.Effects of earth′s spherical curvature andradial heterogeneity in dislocation studies—for a point dislocation.Geophys.Res.Lett.,29(12):1605.
    Wang C S,Dai J G,Zhao X X,et al.2014.Outward-growth of theTibetan Plateau during the Cenozoic:A review.Tectonophysics,621:1-43.
    Wang H.1999.Surface vertical displacements,potential perturbations andgravity change of viscoelastic earth model induced by internal pointdislocations.Geophys.J.Int.,137(2):429-440.
    Wang R J,Martin F L,Martín L,et al.2003.Computation ofdeformation induced by earthquakes in a multi-layered elasticcrust-FORTRAN programs EDGRN/EDCMP.Comput.Geosci.,29(2):195-207.
    Wang R J,Lorenzo-Martín F,Rotha F.2006.PSGRN/PSCMP—anew code for calculating co-and post-seismic deformation,geoid and gravity changes based on the viscoelastic-gravitationaldislocation theory.Comput.Geosci.,32(4):527-541.
    Xu Z Q,Wang Q,Zeng L S,et al.2013.Three-dimensionalextrusion model of the Great Himalaya slice.Geology in China(in Chinese),40(3):671-680.
    Yin A.2006.Cenozoic tectonic evolution of the Himalayan orogenas constrained by along-strike variation of structural geometry,exhumation history,and foreland sedimentation.Earth ScienceFrontiers(in Chinese),13(5):416-515.
    Yin A.2010.Cenozoic tectonic evolution of Asia:A preliminarysynthesis.Tectonophysics,488(1-4):293-325.
    Zhang B,Zhang H,Shi Y L.2015.Equivalent-bodyforce approachon modeling elastic dislocation problem using finite elementmethod.Chinese J.Geophys.(in Chinese),58(5):1666-1674,doi:10.6038/cjg20150518.
    邓起东,程绍平,马冀等.2014.青藏高原地震活动特征及当前地震活动形势.地球物理学报,57(7):2025-2042,doi:10.6038/cjg20140701.
    石耀霖,朱守彪.2006.用GPS位移资料计算应变方法的讨论.大地测量和地球动力学,26(1):1-8.
    石耀霖,曹建玲.2010.库仑应力计算及应用过程中若干问题的讨论———以汶川地震为例.地球物理学报,53(1):102-110,doi:10.3969/j.issn.0001-5733.2010.01.011.
    孙文科.2012.地震位错理论.北京:科学出版社,28-38.
    许志琴,王勤,曾令森等.2013.高喜马拉雅的三维挤出模式.中国地质,40(3):671-680.
    尹安.2006.喜马拉雅造山带新生代构造演化:沿走向变化的构造几何形态、剥露历史和前陆沉积的约束.地学前缘,13(5):416-515.
    张贝,张怀,石耀霖.2015.有限元模拟弹性位错的等效体力方法.地球物理学报,58(5):1666-1674,doi:10.6038/cjg20150518.

版权所有:© 2023 中国地质图书馆 中国地质调查局地学文献中心