基于球体位错理论的地震形变分析
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摘要
地震形变分布特征主要取决于地震断层破裂特征,不同震级的地震引起的形变响应范围存在差异。本文中,我们基于球体位错理论,以5mm的形变测量值为基准,针对逆冲型和走滑型地震断层,分析了MW6.0~MW8.5地震在跨断层法方向上的形变响应范围,提出了地震震级和响应范围的经验公式,并与实际地震(2001年昆仑山口西地震、2013年芦山地震等)结果进行了比较。比较结果显示,经验公式计算结果和实际观测值相符合,可以用于估算MW6.0~MW8.5地震在跨断层法方向的形变响应范围,同时为地震远场形变特征分析与同震、震后形变测量点布设等方面提供参考数据。
Distribution of seismic deformation depends mainly on earthquake fault rupture characteristics,and earthquakes of different magnitude have different deformation response ranges.In this paper,based on heterogeneous spherical dislocation theory,considering the precision of 5 mm,coseismic deformation response ranges are calculated for thrust and strike-slip earthquakes of magnitude MW6.0to MW8.5.Then we calculated the empirical formulae of earthquake magnitudes and response ranges,and compared them with the results of actual earthquakes(the 2001 Kunlun earthquake and the 2013 Lushan earthquakes).Results show that response ranges from the empirical formula match the observed data well,and these empirical formulae can be used to estimate seismic deformation response ranges with the magnitude range from MW6.0to MW8.5,and to provide reference information for analysing far field earthquake deformation characteristics and coseismic and postseismic layout of measuring points.
Distribution of seismic deformation depends mainly on earthquake fault rupture characteristics,and earthquakes of different magnitude have different deformation response ranges.In this paper,based on heterogeneous spherical dislocation theory,considering the precision of 5 mm,coseismic deformation response ranges are calculated for thrust and strike-slip earthquakes of magnitude MW6.0to MW8.5.Then we calculated the empirical formulae of earthquake magnitudes and response ranges,and compared them with the results of actual earthquakes(the 2001 Kunlun earthquake and the 2013 Lushan earthquakes).Results show that response ranges from the empirical formula match the observed data well,and these empirical formulae can be used to estimate seismic deformation response ranges with the magnitude range from MW6.0to MW8.5,and to provide reference information for analysing far field earthquake deformation characteristics and coseismic and postseismic layout of measuring points.
引文
[1]Steketee J A.On Volterra’s dislocations in a semi-infinite elastic medium[J].Can J Phys,1958,(36):192-205.
[2]Maruyama T.Static elastic dislocations in an infinite and semi-infinite medium[J].Bull Earthq Res Inst,1964,(53):289-368.
[3]Okada Y.Surface deformation due to shear and tensile faults in a half-space[J].Bull Seism Soc Am,1985,75(4):1 135-1 154.
[4]Wang R,et al.Computation of deformation induced by earthquakes in a multi-layered elastic crustFORTRAN programs EDGRN/EDCMP[J].Comp Geosci,2003,29:195-207.
[5]Sun W.Potential and gravity changes caused by dislocations in spherically symmetric earth models[J].Bull Earthquake Res InstUniv Tokyo,1992,67:89-238.
[6]Sun W,Okubo S.Surface potential and gravity changes due to internal dislocations in a spherical earth—I.Theory for a point dislocation[J].Geophys J Int,1993,114:569-592.
[7]Sun W,Okubo S.Effects of earth’s spherical curvature and radial heterogeneity in dislocation studies-for a point dislocation[J].Geophys Res Lett,2002,29(12):461-464.
[8]邓起东,于贵华,叶文华.地震地表破裂参数与震级关系的研究[M].国家地震局地质研究所编.活动断裂研究(2).北京:地震出版社,1992,247-264.
[9]Wells D,Coppersmith K.New empirical relationships among magnitude,rupturelength,rupturewidth,rupture area and surface displacement[J].Bull Seism Soc Am,1994,84(4):974-1002.
[10]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):73-86.
[11]Jiang Z,Wang M,et al.GPS constrained coseismic source and slip distribution of the 2013 MW6.6Lushan,China,earthquake and its tectonic implications[J].Geophysical Research Letters,2014,41(2):407-413.
[12]任金卫,王敏.GPS观测的2001年昆仑山口西MS8.1级地震地壳变形[J].2005,25(1):34-44.
[13]Jin H,Wang H.Estimation of the 2001Kunlun earthquake fault slip from GPS coseismic data using Hori’s inverse method[J].Earthquake Science,2009,22(6):609-614.
[2]Maruyama T.Static elastic dislocations in an infinite and semi-infinite medium[J].Bull Earthq Res Inst,1964,(53):289-368.
[3]Okada Y.Surface deformation due to shear and tensile faults in a half-space[J].Bull Seism Soc Am,1985,75(4):1 135-1 154.
[4]Wang R,et al.Computation of deformation induced by earthquakes in a multi-layered elastic crustFORTRAN programs EDGRN/EDCMP[J].Comp Geosci,2003,29:195-207.
[5]Sun W.Potential and gravity changes caused by dislocations in spherically symmetric earth models[J].Bull Earthquake Res InstUniv Tokyo,1992,67:89-238.
[6]Sun W,Okubo S.Surface potential and gravity changes due to internal dislocations in a spherical earth—I.Theory for a point dislocation[J].Geophys J Int,1993,114:569-592.
[7]Sun W,Okubo S.Effects of earth’s spherical curvature and radial heterogeneity in dislocation studies-for a point dislocation[J].Geophys Res Lett,2002,29(12):461-464.
[8]邓起东,于贵华,叶文华.地震地表破裂参数与震级关系的研究[M].国家地震局地质研究所编.活动断裂研究(2).北京:地震出版社,1992,247-264.
[9]Wells D,Coppersmith K.New empirical relationships among magnitude,rupturelength,rupturewidth,rupture area and surface displacement[J].Bull Seism Soc Am,1994,84(4):974-1002.
[10]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):73-86.
[11]Jiang Z,Wang M,et al.GPS constrained coseismic source and slip distribution of the 2013 MW6.6Lushan,China,earthquake and its tectonic implications[J].Geophysical Research Letters,2014,41(2):407-413.
[12]任金卫,王敏.GPS观测的2001年昆仑山口西MS8.1级地震地壳变形[J].2005,25(1):34-44.
[13]Jin H,Wang H.Estimation of the 2001Kunlun earthquake fault slip from GPS coseismic data using Hori’s inverse method[J].Earthquake Science,2009,22(6):609-614.
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