汶川地震震后短期青藏高原东北缘地壳变形特征成因讨论
|
摘要
2007—2009年时段GPS数据资料显示青藏高原东北缘地区地壳运动较前期(1999—2007年时段)发生明显变化。本文分别对汶川地震同震影响、震后粘弹性松弛影响和震后余滑影响进行了分析。结果表明,同震对该区域地壳变形特征的形成存在一定影响,而震后粘弹性松弛和余滑产生的影响均可忽略不计。分析认为,对于中国大陆这种多块体系统而言,现有的震后变形机制并不能充分解释震后短期某些区域地壳运动变形特征的形成,汶川地震震后短期青藏高原东北缘的地壳变形特征的形成可能主要与震后块体运动调整有关。
Crust movement changed obviously in the northeastern margin of Tibetan Plateau zone according to GPS measurements during 2007—2009.This paper analyzed the coseimic effect and postseismic viscoelastic relaxation and afterslip effect respectively.The results show that some deformation was formed because of coseismic effect,but the postseismic viscoelastic relaxation and afterslip effect can be neglected.Some characteristics of postseismic short-term deformation can not be explained adequately by the deformation mechanics for China mainland,which belongs to multi-block system.To a large extent,the form of the characteristic of postseismic short-term deformation in the northeastern margin of Tibetan Plateau zone may be related to adjustment movement of blocks.
Crust movement changed obviously in the northeastern margin of Tibetan Plateau zone according to GPS measurements during 2007—2009.This paper analyzed the coseimic effect and postseismic viscoelastic relaxation and afterslip effect respectively.The results show that some deformation was formed because of coseismic effect,but the postseismic viscoelastic relaxation and afterslip effect can be neglected.Some characteristics of postseismic short-term deformation can not be explained adequately by the deformation mechanics for China mainland,which belongs to multi-block system.To a large extent,the form of the characteristic of postseismic short-term deformation in the northeastern margin of Tibetan Plateau zone may be related to adjustment movement of blocks.
引文
[1]Yan H,Wang K.Spherical-Earth finite element model of short-term postseismic deformation follow-ing the 2004Sumatra earthquake[J].J Geophys Res,2012,117(B05404).
[2]Freed A M,Hirth G,Behn M D.Using short-term postseismic displacements to infer the ambientdeformation conditions of the upper mantle[J].J Geophys Res,2012,117(B01409).
[3]Jouanne F,Awan A,Madji A,et al.Postseismic deformation in Pakistan after the 8October 2005earthquake:Evidence of afterslip along a flat north of the Balakot-Bagh thrust[J].J Geophys Res,2011,116(B07401).
[4]Jonsson S,Segall P,Pedersen R,et al.Post-earthquake ground movements correlated to pore-pres-sure transients[J].Nature,2003,424(6 945):179-183.
[5]Rice J R,Gu J C.Earthquake aftereffects and triggered seismic phenomena[J].Pure and AppliedGeophysics,1983,121(2):187-219.
[6]Barbot S,Fialko Y.A unified continuum representation of post-seismic relaxation mechanisms:semi-analytic models of afterslip,poroelastic rebound and viscoelastic flow[J].Geophys J Int,2010,182(3):1 124-1 140.
[7]武艳强,江在森,杨国华,等.南北地震带北段近期地壳变形特征研究[J].武汉大学学报(信息科学版),2012,37(9):1045-1048.
[8]杨国华,杨博,占伟,等.玉树和汶川地震前后区域水平形变的空间分布[J].地震,2012,32(2):40-51.
[9]赵静,江在森,武艳强,等.汶川地震前后川滇块体应变与断裂变形特征研究[J].大地测量与地球动力学,2011,31(5):30-34.
[10]徐锡伟,闻学泽,叶建青,等.汶川MS8.0地震地表破裂带及其发震构造[J].地震地质,2008,30(3):597-629.
[11]Herring T A,King R W,McClusky S C.GAMIT Reference Manual,Release 10.3.MassachussettsInstitute Technology,2006(http:∥www-gpsg.mit.edu/～simon/gtgk/index.htm).
[12]Herring T A,King R W,McClusky S C.GLOBK Reference Manual,Release 10.3.MassachussettsInstitute Technology,2006(http:∥www-gpsg.mit.edu/～simon/gtgk/index.htm).
[13]Sun,W,Okubo S.Effects of earth's spherical curvature and radial heterogeneity in dislocation stud-ies for a point dislocation[J].Geophys Res Lett,2002,29(12):10.1029/2001GL014497.
[14]付广裕,孙文科.球体位错理论计算程序的总体设计与具体实现[J].地震,2012,32(2):73-87.
[15]王卫民,赵连峰,李娟,等.四川汶川8.0级地震震源过程[J].地球物理学报,2008,51(005):1 403-1 410.
[16]Xiong X,Shan B,Zheng Y,et al.Stress transfer and its implication for earthquake hazard on theKunlun fault,Tibet[J].Tectonophysics,2010,482(1):216-225.
[17]Pollitz F F,Wicks C,Thatcher W.Mantle flow beneath a continental strike-slip fault:Postseismicdeformation after the 1999Hector Mine earthquake[J].Science,2001,293(5 536):1 814-1 818.
[18]邵志刚,傅容珊,薛霆虓.以Burgers体模型模拟震后粘弹性松弛效应[J].大地测量与地球动力学,2007,27(5):31-37.
[19]邵志刚,周龙泉,蒋长胜,等.2008年汶川MS8.0地震对周边断层地震活动的影响[J].地球物理学报,2010,53(8):1784-1795.
[20]Wang R J,Lorenzo M F,Roth F.PSGRN/PSCMP—a new code for calculating co-and post-seismicdeformation,geoid and gravity changes based on the viscoelastic-gravitational dislocation theory[J].Computers&Geosciences,2006,32(4):527-541.
[21]Johanson I A,Bürgmann R.Coseismic and postseismic slip from the 2003San Simeon earthquakeand their effects on backthrust slip and the 2004Parkfield earthquake[J].J Geophys Res,2010,115(B07411).
[22]Pollitz F F,Bürgmann R,Segall P,et al.Joint estimation of afterslip rate and postseismic relaxationfollowing the 1989Loma Prieta earthquake[J].J Geophys Res,1998,103(B11):26 975-26 992.
[23]Shen Z K,Sun J B,Zhang P Z,et al.Slip maxima at fault junctions and rupturing of barriers duringthe 2008Wenchuan earthquake[J].Nature Geosci,2009,2(10):718-724.
[24]Shao Z G,Wang R J,Wu Y Q,et al.Rapid afterslip and short-term viscoelastic relaxation followingthe 2008 MW7.9Wenchuan earthquake[J].Earthquake Science,2011,24(2):163-175.
[25]张培震,邓起东,张国民,等.中国大陆的强震活动与活动地块[J].中国科学(D辑),2003,33(1):12-20.
[2]Freed A M,Hirth G,Behn M D.Using short-term postseismic displacements to infer the ambientdeformation conditions of the upper mantle[J].J Geophys Res,2012,117(B01409).
[3]Jouanne F,Awan A,Madji A,et al.Postseismic deformation in Pakistan after the 8October 2005earthquake:Evidence of afterslip along a flat north of the Balakot-Bagh thrust[J].J Geophys Res,2011,116(B07401).
[4]Jonsson S,Segall P,Pedersen R,et al.Post-earthquake ground movements correlated to pore-pres-sure transients[J].Nature,2003,424(6 945):179-183.
[5]Rice J R,Gu J C.Earthquake aftereffects and triggered seismic phenomena[J].Pure and AppliedGeophysics,1983,121(2):187-219.
[6]Barbot S,Fialko Y.A unified continuum representation of post-seismic relaxation mechanisms:semi-analytic models of afterslip,poroelastic rebound and viscoelastic flow[J].Geophys J Int,2010,182(3):1 124-1 140.
[7]武艳强,江在森,杨国华,等.南北地震带北段近期地壳变形特征研究[J].武汉大学学报(信息科学版),2012,37(9):1045-1048.
[8]杨国华,杨博,占伟,等.玉树和汶川地震前后区域水平形变的空间分布[J].地震,2012,32(2):40-51.
[9]赵静,江在森,武艳强,等.汶川地震前后川滇块体应变与断裂变形特征研究[J].大地测量与地球动力学,2011,31(5):30-34.
[10]徐锡伟,闻学泽,叶建青,等.汶川MS8.0地震地表破裂带及其发震构造[J].地震地质,2008,30(3):597-629.
[11]Herring T A,King R W,McClusky S C.GAMIT Reference Manual,Release 10.3.MassachussettsInstitute Technology,2006(http:∥www-gpsg.mit.edu/～simon/gtgk/index.htm).
[12]Herring T A,King R W,McClusky S C.GLOBK Reference Manual,Release 10.3.MassachussettsInstitute Technology,2006(http:∥www-gpsg.mit.edu/～simon/gtgk/index.htm).
[13]Sun,W,Okubo S.Effects of earth's spherical curvature and radial heterogeneity in dislocation stud-ies for a point dislocation[J].Geophys Res Lett,2002,29(12):10.1029/2001GL014497.
[14]付广裕,孙文科.球体位错理论计算程序的总体设计与具体实现[J].地震,2012,32(2):73-87.
[15]王卫民,赵连峰,李娟,等.四川汶川8.0级地震震源过程[J].地球物理学报,2008,51(005):1 403-1 410.
[16]Xiong X,Shan B,Zheng Y,et al.Stress transfer and its implication for earthquake hazard on theKunlun fault,Tibet[J].Tectonophysics,2010,482(1):216-225.
[17]Pollitz F F,Wicks C,Thatcher W.Mantle flow beneath a continental strike-slip fault:Postseismicdeformation after the 1999Hector Mine earthquake[J].Science,2001,293(5 536):1 814-1 818.
[18]邵志刚,傅容珊,薛霆虓.以Burgers体模型模拟震后粘弹性松弛效应[J].大地测量与地球动力学,2007,27(5):31-37.
[19]邵志刚,周龙泉,蒋长胜,等.2008年汶川MS8.0地震对周边断层地震活动的影响[J].地球物理学报,2010,53(8):1784-1795.
[20]Wang R J,Lorenzo M F,Roth F.PSGRN/PSCMP—a new code for calculating co-and post-seismicdeformation,geoid and gravity changes based on the viscoelastic-gravitational dislocation theory[J].Computers&Geosciences,2006,32(4):527-541.
[21]Johanson I A,Bürgmann R.Coseismic and postseismic slip from the 2003San Simeon earthquakeand their effects on backthrust slip and the 2004Parkfield earthquake[J].J Geophys Res,2010,115(B07411).
[22]Pollitz F F,Bürgmann R,Segall P,et al.Joint estimation of afterslip rate and postseismic relaxationfollowing the 1989Loma Prieta earthquake[J].J Geophys Res,1998,103(B11):26 975-26 992.
[23]Shen Z K,Sun J B,Zhang P Z,et al.Slip maxima at fault junctions and rupturing of barriers duringthe 2008Wenchuan earthquake[J].Nature Geosci,2009,2(10):718-724.
[24]Shao Z G,Wang R J,Wu Y Q,et al.Rapid afterslip and short-term viscoelastic relaxation followingthe 2008 MW7.9Wenchuan earthquake[J].Earthquake Science,2011,24(2):163-175.
[25]张培震,邓起东,张国民,等.中国大陆的强震活动与活动地块[J].中国科学(D辑),2003,33(1):12-20.
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