升降轨InSAR数据约束下的2007年阿里地震反演分析
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摘要
2007年5月5日,西藏阿里地区发生了Mw6.1级地震。本文采用Envisat卫星的升、降轨SAR数据获取地震的精确同震地表位移,然后基于弹性半空间位错模型,分别采用MPSO非线性和最小二乘线性反演算法确定了断层几何参数和滑动分布模型。结果表明,分布式滑动分布模型能较好地解释观测到的InSAR地表形变场。地震发震断层为走向158°、倾角43°的西南倾断层,主要的滑动量集中在7~12km的深度,最大滑动量约0.3m,位于9km的深度。反演给出的地震矩为1.24×1018 Nm,与地震学结果相一致。
On 5th May,2007,aMw6.1earthquake occurred in the Ali region,China.In this study,ascending and descending tracks of ASAR images collected by Envisat satellite are employed to derive the precise coseismic surface displacements,then nonlinear MPSO algorithm and linear least-square method with elastic half-space dislocation model are used to estimate the fault geometry and coseismic slip distribution.Our model suggests that the distributed slip mode can fit the observations very well.The earthquake fault is a normal fault with a strike of158°,a dip of 43°and dipping to southwest.The slip mainly occurs within 7~12km along the orientation,with a maximum slip of 0.3mat a depth of 9km.The determined geodetic moment is 1.24×1018 Nm,which is consistent with seismological results.
On 5th May,2007,aMw6.1earthquake occurred in the Ali region,China.In this study,ascending and descending tracks of ASAR images collected by Envisat satellite are employed to derive the precise coseismic surface displacements,then nonlinear MPSO algorithm and linear least-square method with elastic half-space dislocation model are used to estimate the fault geometry and coseismic slip distribution.Our model suggests that the distributed slip mode can fit the observations very well.The earthquake fault is a normal fault with a strike of158°,a dip of 43°and dipping to southwest.The slip mainly occurs within 7~12km along the orientation,with a maximum slip of 0.3mat a depth of 9km.The determined geodetic moment is 1.24×1018 Nm,which is consistent with seismological results.
引文
[1]ELLIOTT J R,WALTERS R J,ENGLANDP C,et al.Extension on the Tibetan Plateau:Recent Normal Faulting Measured by InSAR and Body Wave Seismology[J].Geophysics Journal International,2010,183(2):503-535.
[2]HAN Tonglin.Active Tectonic of Xizang[M].Beijing:The Geological Publishing House,1987.(韩同林.西藏活动构造[M].北京:地质出版社,1987.)
[3]WEN Yangmao,XU Caijun.Ms 7.9 Mani Earthquake Slip Distribution Inversion by a Sensitivity-based Iterative Fitting Method[J].Geomatics and Information Science of Wuhan University,2009,34(6):732-735.(温扬茂,许才军.基于敏感度的迭代拟合法反演玛尼Ms 7.9级地震滑动分布[J].武汉大学学报:信息科学版,2009,34(6):732-735.)
[4]WEN Yangmao,XU Caijun,LIU Yang,et al.Source Parameters of 2008 Qinghai Dachaidan Mw6.3 Earthquake from InSAR Inversion and Automated Fault Discretization Method[J].Geomatics and Information Science of Wuhan University,2012,37(4):458-462.(温扬茂,许才军,刘洋,等.利用断层自动剖分技术的2008年青海大柴旦Mw6.3级地震InSAR反演研究[J].武汉大学学报:信息科学版,2012,37(4):458-462.)
[5]WANG Leyang,XU Caijun,WEN Yangmao.Fault Parameters of 2008Qinghai Dacaidan Mw 6.3Earthquake from STLN Inversion and InSAR Data[J].Acta Geodaetica et Cartographica Sinica,2013,42(2):168-176.(王乐洋,许才军,温扬茂.利用STLN和InSAR数据反演2008年青海大柴旦Mw 6.3级地震断层参数[J].测绘学报,2013,42(2):168-176.)
[6]FIALKO Y,SANDWELL D,SIMONS M,et al.Threedimensional Deformation Caused by the Bam,Iran,Earthquake and the Origin of Shallow Slip Deficit[J].Nature,2005,435(7040):295-299.
[7]WERNER C,WEGMULLER,STROZZI T,et al.GAMMA SAR and Interferometric Processing Software[C]∥Proceedings of the ERS-ENVISAT Symposium.Gothenburg:[s.n.],2000.
[8]MASSONNET D,ROSSI M,CARMONA C,et al.The Displacement Field of the Landers Earthquake Mapped by Radar Interferometry[J].Nature,364(6433):138-142.
[9]FARRT G,ROSENP A,CARO E,et al.The Shuttle Radar Topography Mission[J].Reviews of Geophysics,2007,45(2):20-24.
[10]WEN Y,XU C,LIU Y,et al.Coseismic Slip in the 2010Yushu Earthquake(China),Constrained by Wide-swath and Strip-map InSAR[J].Natural Hazards and Earth System Sciences,2013,13:35-44.
[11]HANSSEN R F.Radar Interferometry:Data Interpretation and Error Analysis[M].New York:Kluwer Academic Publishers,2001.
[12]LOHMAN R B,SIMONS M.Some Thoughts on the Use of InSAR Data to Constrain Models of Surface Deformation:Noise Structure and Data Down Sampling[J].Geochemistry,Geophysics,Geosystems,2005,6(1),doi:10.1029/2004GC000841.
[13]WRIGHT T J,LU Z,WICKS C.Source Model for the Mw6.7,23 October 2002,Nenana Mountain Earthquake(Alaska)from InSAR[J].Geophysical Research Letters,2003,30(18),doi:10.1029/2003GL018014.
[14]WEN Yangmao,HE Ping,XU Caijun,et al.Source Parameters of the 2009L’Aquila Earthquake,Italy from ENVISAT and ALOS Satellite SAR Images[J].Chinese Journal of Geophysics,2012,55(1):53-65.(温扬茂,何平,许才军,等.联合ENVISAT和ALOS卫星影像确定L’Aquila地震震源机制[J].地球物理学报,2012,55(1):53-65.)
[15]OKADA Y.Surface Deformation due to Shear and Tensile Faults in a Half-space[J].Bulletin of the Seismological Society of America,1985,75(4):1135-1154.
[16]BRGMANN R,AYHAN M E,FIELDING E J,et al.Deformation during the 12 November 1999 Düzce,Turkey,Earthquake,from GPS and InSAR Data[J].Bulletin of the Seismological Society of America,2002,92(1):161-171.
[17]FENG W P,LI Z H,ELLIOTT J R,et al.The 2011Mw6.8 Burma Earthquake:Fault Constraints Provided by Multiple SAR Techniques[J].Geophysics Journal International,2013,195(1):650-660.
[18]FENG Wanpeng,LI Zhenhong.A Novel Hybrid PSO/Simplex Algorithm for Determining Earthquake Source Parameters Using InSAR Data[J].Progress in Geophysics,2010,25(4):1189-1196.(冯万鹏,李振洪.InSAR资料约束下震源参数的PSO混合算法反演策略[J].地球物理学进展,2010,25(4):1189-1196.)
[19]JONSSON S,ZEBKER H,SEGALL P,et al.Fault Slip Distribution of the 1999 Mw7.1 Hector Mine,California Earthquake,Estimated from Satellite Radar and GPS Measurements[J].Bulletin of the Seismological Society of America,2002,92(4):1377-1389.
[20]PARSONS B,WRIGHT T,ROWE P,et al.The 1994Sefidabeh(Eastern Iran)Earthquakes Revisited:New Evidence from Satellite Radar Interferometry and Carbonate Dating about the Growth of an Active Fold above a Blind Thrust Fault[J].Geophysics Journal International,2006,164(1):202-217.
[2]HAN Tonglin.Active Tectonic of Xizang[M].Beijing:The Geological Publishing House,1987.(韩同林.西藏活动构造[M].北京:地质出版社,1987.)
[3]WEN Yangmao,XU Caijun.Ms 7.9 Mani Earthquake Slip Distribution Inversion by a Sensitivity-based Iterative Fitting Method[J].Geomatics and Information Science of Wuhan University,2009,34(6):732-735.(温扬茂,许才军.基于敏感度的迭代拟合法反演玛尼Ms 7.9级地震滑动分布[J].武汉大学学报:信息科学版,2009,34(6):732-735.)
[4]WEN Yangmao,XU Caijun,LIU Yang,et al.Source Parameters of 2008 Qinghai Dachaidan Mw6.3 Earthquake from InSAR Inversion and Automated Fault Discretization Method[J].Geomatics and Information Science of Wuhan University,2012,37(4):458-462.(温扬茂,许才军,刘洋,等.利用断层自动剖分技术的2008年青海大柴旦Mw6.3级地震InSAR反演研究[J].武汉大学学报:信息科学版,2012,37(4):458-462.)
[5]WANG Leyang,XU Caijun,WEN Yangmao.Fault Parameters of 2008Qinghai Dacaidan Mw 6.3Earthquake from STLN Inversion and InSAR Data[J].Acta Geodaetica et Cartographica Sinica,2013,42(2):168-176.(王乐洋,许才军,温扬茂.利用STLN和InSAR数据反演2008年青海大柴旦Mw 6.3级地震断层参数[J].测绘学报,2013,42(2):168-176.)
[6]FIALKO Y,SANDWELL D,SIMONS M,et al.Threedimensional Deformation Caused by the Bam,Iran,Earthquake and the Origin of Shallow Slip Deficit[J].Nature,2005,435(7040):295-299.
[7]WERNER C,WEGMULLER,STROZZI T,et al.GAMMA SAR and Interferometric Processing Software[C]∥Proceedings of the ERS-ENVISAT Symposium.Gothenburg:[s.n.],2000.
[8]MASSONNET D,ROSSI M,CARMONA C,et al.The Displacement Field of the Landers Earthquake Mapped by Radar Interferometry[J].Nature,364(6433):138-142.
[9]FARRT G,ROSENP A,CARO E,et al.The Shuttle Radar Topography Mission[J].Reviews of Geophysics,2007,45(2):20-24.
[10]WEN Y,XU C,LIU Y,et al.Coseismic Slip in the 2010Yushu Earthquake(China),Constrained by Wide-swath and Strip-map InSAR[J].Natural Hazards and Earth System Sciences,2013,13:35-44.
[11]HANSSEN R F.Radar Interferometry:Data Interpretation and Error Analysis[M].New York:Kluwer Academic Publishers,2001.
[12]LOHMAN R B,SIMONS M.Some Thoughts on the Use of InSAR Data to Constrain Models of Surface Deformation:Noise Structure and Data Down Sampling[J].Geochemistry,Geophysics,Geosystems,2005,6(1),doi:10.1029/2004GC000841.
[13]WRIGHT T J,LU Z,WICKS C.Source Model for the Mw6.7,23 October 2002,Nenana Mountain Earthquake(Alaska)from InSAR[J].Geophysical Research Letters,2003,30(18),doi:10.1029/2003GL018014.
[14]WEN Yangmao,HE Ping,XU Caijun,et al.Source Parameters of the 2009L’Aquila Earthquake,Italy from ENVISAT and ALOS Satellite SAR Images[J].Chinese Journal of Geophysics,2012,55(1):53-65.(温扬茂,何平,许才军,等.联合ENVISAT和ALOS卫星影像确定L’Aquila地震震源机制[J].地球物理学报,2012,55(1):53-65.)
[15]OKADA Y.Surface Deformation due to Shear and Tensile Faults in a Half-space[J].Bulletin of the Seismological Society of America,1985,75(4):1135-1154.
[16]BRGMANN R,AYHAN M E,FIELDING E J,et al.Deformation during the 12 November 1999 Düzce,Turkey,Earthquake,from GPS and InSAR Data[J].Bulletin of the Seismological Society of America,2002,92(1):161-171.
[17]FENG W P,LI Z H,ELLIOTT J R,et al.The 2011Mw6.8 Burma Earthquake:Fault Constraints Provided by Multiple SAR Techniques[J].Geophysics Journal International,2013,195(1):650-660.
[18]FENG Wanpeng,LI Zhenhong.A Novel Hybrid PSO/Simplex Algorithm for Determining Earthquake Source Parameters Using InSAR Data[J].Progress in Geophysics,2010,25(4):1189-1196.(冯万鹏,李振洪.InSAR资料约束下震源参数的PSO混合算法反演策略[J].地球物理学进展,2010,25(4):1189-1196.)
[19]JONSSON S,ZEBKER H,SEGALL P,et al.Fault Slip Distribution of the 1999 Mw7.1 Hector Mine,California Earthquake,Estimated from Satellite Radar and GPS Measurements[J].Bulletin of the Seismological Society of America,2002,92(4):1377-1389.
[20]PARSONS B,WRIGHT T,ROWE P,et al.The 1994Sefidabeh(Eastern Iran)Earthquakes Revisited:New Evidence from Satellite Radar Interferometry and Carbonate Dating about the Growth of an Active Fold above a Blind Thrust Fault[J].Geophysics Journal International,2006,164(1):202-217.
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