2013年芦山Ms 7.0级地震断层参数模型反演
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摘要
2013年4月20日四川芦山地区发生了Ms 7.0级地震。利用GPS三维同震形变数据获取地表形变场,基于位错模型反演芦山地震的断层几何参数及滑动分布。首先采用多峰值颗粒群算法(multiple peak particle swarm optimization, MPSO)得到断层几何参数,其中断层走向206.47°,倾角44.11°,长度21.94 km,离地表最浅处为7.66 km,最深处为17.84 km。为了反演断层面的精细滑动分布,分析地震所在的龙门山断裂西南段破裂面具有的铲状型特征,将芦山地震破裂面确立为铲状模型,即将断层的倾角预设为上陡下缓,倾角变化范围为21°～50°。结果显示,断层破裂面在不同深度区域出现了两个滑动峰值,其中最大滑动量为0.68 m,深度位于13 km。地震释放的能量为1.47×10~(19) N·m,对应的矩震级为Mw 6.74,与地震学的研究结果一致。
On April 20 th 2013, Ms 7.0 earthquake occurred on the southern section of the Longmen Shan fault, in Sichuan Province. In this research, the three-dimensional coseismic displacement field that GPS data from 33 continuous stations are used to invert for fault geometry parameters and the slip distribution. The MPSO(multiple peak particle swarm optimization) algorithm has been successfully applied to invert for the fault model parameters.Compared with the commonly used algorithm, such as genetic algorithm, simulated annealing and the overall minimum norm optimization algorithm, MPSO algorithm has the advantages of less control parameters, high global convergence efficiency, and is very suitable for nonlinear inversion of fault parameters. The result indicates that the seismogenic fault is a thrust with a strike of 206.47°, a dip of 44.11°, and length of 21.94 km. The minimum and maximum depth is 7.66 km and 17.84 km, respectively. The fracture surface was determined as listric surface by analysis. In order to obtain the detailed slip distribution, the listric surface model is set with the default dip angle varying from 50° on the top boundary of the surface to 21° on the bottom boundary. Our inversion result shows that the rupture surface has two slip peaks at different depths. The maximum slip is 0.68 m at the depth of 13 km. The inverted geodetic moment is 1.47×10~(19) N·m and the moment magnitude Mw is 6.74, which is consistent with the result of seismology.
On April 20 th 2013, Ms 7.0 earthquake occurred on the southern section of the Longmen Shan fault, in Sichuan Province. In this research, the three-dimensional coseismic displacement field that GPS data from 33 continuous stations are used to invert for fault geometry parameters and the slip distribution. The MPSO(multiple peak particle swarm optimization) algorithm has been successfully applied to invert for the fault model parameters.Compared with the commonly used algorithm, such as genetic algorithm, simulated annealing and the overall minimum norm optimization algorithm, MPSO algorithm has the advantages of less control parameters, high global convergence efficiency, and is very suitable for nonlinear inversion of fault parameters. The result indicates that the seismogenic fault is a thrust with a strike of 206.47°, a dip of 44.11°, and length of 21.94 km. The minimum and maximum depth is 7.66 km and 17.84 km, respectively. The fracture surface was determined as listric surface by analysis. In order to obtain the detailed slip distribution, the listric surface model is set with the default dip angle varying from 50° on the top boundary of the surface to 21° on the bottom boundary. Our inversion result shows that the rupture surface has two slip peaks at different depths. The maximum slip is 0.68 m at the depth of 13 km. The inverted geodetic moment is 1.47×10~(19) N·m and the moment magnitude Mw is 6.74, which is consistent with the result of seismology.
引文
[1] Xu Xiwei, Wen Xueze, Han Zhujun, et al. Lushan Ms 7.0 Earthquake: A Blind Reserve-Fault Earthquake[J]. Chinese Science Bulletin, 2013, 58(20): 1 887-1 893(徐锡伟,闻学泽,韩竹军,等. 四川芦山7.0级强震: 一次典型的盲逆断层型地震[J]. 科学通报,2013, 58(20): 1 887-1 893)
[2] Wang Weimin, Hao Jinlai, Yao Zhenxing. Preliminary Result for Rupture Process of Apr. 20, 2013, Lushan Earthquake, Sichuan, China[J]. Chinese Journal of Geophysics, 2013, 56(4):1 412-1 417(王卫民,郝金来,姚振兴. 2013年4月20日四川芦山地震震源破裂过程反演初步结果[J]. 地球物理学报, 2013, 56 (4):1 412-1 417)
[3] Liu Yunhua, Wang Chisheng, Shan Xinjian, et al. Results of SAR Differential Interferometry for the Co-seismic Deformation and Source Parameter of the Ms 7.0 Lushan Earthquake[J]. Chinese Journal of Geophysics, 2014, 57(8):2 495-2 506(刘云华,汪驰升,单新建, 等. 芦山Ms 7.0级地震InSAR形变观测及震源参数反演[J]. 地球物理学报, 2014, 57(8):2 495-2 506)
[4] Jiang Z S, Wang M, Wang Y Z, et al. GPS Constrained Coseismic Source and Slip Distribution of the 2013 Mw 6.6 Lushan China, Earthquake and Its Tectonic Implications[J]. Geophysical Research Letters, 2014, 41 (2):407-413
[5] Tan Kai, Wang Qi, Ding Kaihua, et al. Rupture Models of the 2013 Lushan Earthquake Constrained by Nearfield Displacements and Its Tectonic Implications[J]. Chinese Journal of Geophysics, 2015, 58(9):3 169- 3 182(谭凯, 王琪, 丁开华,等. 近场位移数据约束的2013年芦山地震破裂模型及其构造意义[J]. 地球物理学报, 2015, 58(9): 3 169-3 182)
[6] Tan Kai, Yang Shaomin, Qiao Xuejun, et al. Rupture of Ramp-decollement Faults in the 2008 Wenchuan Earthquake-Geodetic Evidence for the Uplift of the Longmen Shan Driven by Convergent Deformation[J]. Chinese Journal of Geophysics, 2013,56(5):1 506-1 516(谭凯,杨少敏,乔学军,等. 2008年汶川中断坡-滑脱断层破裂:龙门山挤压隆升的大地测量证据[J].地球物理学报,2013,56(5): 1 506-1 516)
[7] Xu Caijun, Liu Yang, Wen Yangmao. Mw 7.9 Wenchuan Earthquake Slip Distribution Inversion from GPS Measurements[J]. Acta Geodaetica et Cartographica Sinica, 2009, 38(3):195-201(许才军,刘洋,温扬茂. 利用GPS资料反演汶川Mw 7.9级地震滑动分布[J]. 测绘学报, 2009, 38(3):195-201)
[8] Yi Guixi,Long Feng, Vallage A, et al. Focal Mechanism and Tectonic Deformation in the Seimogenic Area of the 2013 Lushan Earthquake Sequence, Southwestern China[J]. Chinese Journal of Geophysics, 2016, 59(10):3 711-3 731(易桂喜,龙锋,Vallage A,等. 2013年芦山地震序列震源机制与震源区构造变形特征分析[J].地球物理学报,2016, 59(10): 3 711-3 731)
[9] 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):1 189-1 196(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):1 189-1 196)
[10] Feng Wanpeng, Xu Lisheng, Li Zhenhong. Fault Parameters of the October 2008 Damxung Mw 6.3 Earthquake from InSAR Inversion and Its Tectonic Implication[J]. Chinese Journal of Geophysics, 2010, 53(5):1 134-1 142 (冯万鹏, 许力生, 李振洪. 2008年10月当雄Mw 6.3级地震断层参数的InSAR反演及其构造意义[J]. 地球物理学报, 2010, 53(5):1 134-1 142)
[11] Wen Yangmao, Xu Caijun, Liu Yang, et al. The 2007 Ali Earthquake Inversion from Ascending and Descending InSAR Observation[J]. Acta Geodaetica et Cartographica Sinica, 2015,44(6):649-654 (温扬茂,许才军,刘洋,等. 升降轨InSAR数据约束下的2007年阿里地震反演分析[J]. 测绘学报, 2015,44(6):649-654)
[12] Nunnari G, Puglisi G, Guglielmino F. Inversion of SAR Data in Active Volconic Areas by Optimization Techniques[J]. Nonlinear Processes in Geophysics, 2005, 12: 863-870
[13] Jonssono S,Zebker H,Segall P, et al. Fault Slip Distribution of the 1999 Mw 7.1 Hector Mine, Cali-fornia Earthquake, Estimated from Satellite Radar and GPS Measurements[J]. Bull Seism Soc Am, 2002, 92(4): 1 377-1 389
[14] Pedersen R, Jonsson S, Arnadottir T, et al. Fault Slip Distribution of Two June 2000 Mw 6.5 Earthquake in South Iceland Estimated from Joint Inversion of InSAR and GPS Measurements[J]. Earth and Planetary Science Letters, 2003, 213: 487-502
[15] Wang Leyang,Xu Caijun,Wen Yangmao. Fault Parameters of 2008 Qinghai Dachaidan Mw 6.3 Earthquake 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)
[16] Zhang Peizhen. Current Tectonic Deformation, Strain Distribution and Deep Dynamic Process of Eastern Margin of Qinghai-Tibet Plateau in Western Sichuan[J]. Science China: Earth Sciences, 2008, 38(9):1 041-1 056(张培震. 青藏高原东缘川西的现今构造变形、应变分配与深部动力过程[J]. 中国科学D辑:地球科学,2008, 38(9):1 041-1 056)
[17] Xu X W, Wen X Z, Yu G H, et al.Coseismic Reverse- and Oblique-Slip Surface Faulting Generated by the 2008 Mw 7.9 Wenchuan Earthquake, China[J]. Geology, 2009, 37: 515-518
[18] Zhang P, Wen X, Shen Z, et al. Oblique, High-Angle, Listric-Reserve Faulting and Associated Development of Strain: The Wenchuan Earthquake of May 12, 2008, Sichuan, China[J]. Annu Rev Earth Planet Sci, 2010, 38: 353-382
[19] Xu Caijun, Yin Zhi. Progress in Inversion for Tectonic Stress-Strain Fields Using Geodetic Data[J]. Geomatics and Information Science of Wuhan University, 2014,39(10):1 135-1 146(许才军,尹智. 利用大地测量资料反演构造应力应变场研究进展[J].武汉大学学报·信息科学版, 2014, 39(10):1 135-1 146
[20] 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): 1 135-1 154
[21] Okada Y. Internal Deformation due to Shear and Tensile Faults in a Half-Space[J]. Bulletin of the Seismological Society of America,1992,82(2): 1 018-1 140
[22] Funning G J, Parsons B, Wright T J, et al. Surface Displacements and Source Parameters of the 2003 Bam (Iran) Earthquake from Envisat Advanced Synthetic Aperture Radar Imagery[J]. Journal of Geophysical Research, 2005, 110(B09): 406-411
[2] Wang Weimin, Hao Jinlai, Yao Zhenxing. Preliminary Result for Rupture Process of Apr. 20, 2013, Lushan Earthquake, Sichuan, China[J]. Chinese Journal of Geophysics, 2013, 56(4):1 412-1 417(王卫民,郝金来,姚振兴. 2013年4月20日四川芦山地震震源破裂过程反演初步结果[J]. 地球物理学报, 2013, 56 (4):1 412-1 417)
[3] Liu Yunhua, Wang Chisheng, Shan Xinjian, et al. Results of SAR Differential Interferometry for the Co-seismic Deformation and Source Parameter of the Ms 7.0 Lushan Earthquake[J]. Chinese Journal of Geophysics, 2014, 57(8):2 495-2 506(刘云华,汪驰升,单新建, 等. 芦山Ms 7.0级地震InSAR形变观测及震源参数反演[J]. 地球物理学报, 2014, 57(8):2 495-2 506)
[4] Jiang Z S, Wang M, Wang Y Z, et al. GPS Constrained Coseismic Source and Slip Distribution of the 2013 Mw 6.6 Lushan China, Earthquake and Its Tectonic Implications[J]. Geophysical Research Letters, 2014, 41 (2):407-413
[5] Tan Kai, Wang Qi, Ding Kaihua, et al. Rupture Models of the 2013 Lushan Earthquake Constrained by Nearfield Displacements and Its Tectonic Implications[J]. Chinese Journal of Geophysics, 2015, 58(9):3 169- 3 182(谭凯, 王琪, 丁开华,等. 近场位移数据约束的2013年芦山地震破裂模型及其构造意义[J]. 地球物理学报, 2015, 58(9): 3 169-3 182)
[6] Tan Kai, Yang Shaomin, Qiao Xuejun, et al. Rupture of Ramp-decollement Faults in the 2008 Wenchuan Earthquake-Geodetic Evidence for the Uplift of the Longmen Shan Driven by Convergent Deformation[J]. Chinese Journal of Geophysics, 2013,56(5):1 506-1 516(谭凯,杨少敏,乔学军,等. 2008年汶川中断坡-滑脱断层破裂:龙门山挤压隆升的大地测量证据[J].地球物理学报,2013,56(5): 1 506-1 516)
[7] Xu Caijun, Liu Yang, Wen Yangmao. Mw 7.9 Wenchuan Earthquake Slip Distribution Inversion from GPS Measurements[J]. Acta Geodaetica et Cartographica Sinica, 2009, 38(3):195-201(许才军,刘洋,温扬茂. 利用GPS资料反演汶川Mw 7.9级地震滑动分布[J]. 测绘学报, 2009, 38(3):195-201)
[8] Yi Guixi,Long Feng, Vallage A, et al. Focal Mechanism and Tectonic Deformation in the Seimogenic Area of the 2013 Lushan Earthquake Sequence, Southwestern China[J]. Chinese Journal of Geophysics, 2016, 59(10):3 711-3 731(易桂喜,龙锋,Vallage A,等. 2013年芦山地震序列震源机制与震源区构造变形特征分析[J].地球物理学报,2016, 59(10): 3 711-3 731)
[9] 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):1 189-1 196(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):1 189-1 196)
[10] Feng Wanpeng, Xu Lisheng, Li Zhenhong. Fault Parameters of the October 2008 Damxung Mw 6.3 Earthquake from InSAR Inversion and Its Tectonic Implication[J]. Chinese Journal of Geophysics, 2010, 53(5):1 134-1 142 (冯万鹏, 许力生, 李振洪. 2008年10月当雄Mw 6.3级地震断层参数的InSAR反演及其构造意义[J]. 地球物理学报, 2010, 53(5):1 134-1 142)
[11] Wen Yangmao, Xu Caijun, Liu Yang, et al. The 2007 Ali Earthquake Inversion from Ascending and Descending InSAR Observation[J]. Acta Geodaetica et Cartographica Sinica, 2015,44(6):649-654 (温扬茂,许才军,刘洋,等. 升降轨InSAR数据约束下的2007年阿里地震反演分析[J]. 测绘学报, 2015,44(6):649-654)
[12] Nunnari G, Puglisi G, Guglielmino F. Inversion of SAR Data in Active Volconic Areas by Optimization Techniques[J]. Nonlinear Processes in Geophysics, 2005, 12: 863-870
[13] Jonssono S,Zebker H,Segall P, et al. Fault Slip Distribution of the 1999 Mw 7.1 Hector Mine, Cali-fornia Earthquake, Estimated from Satellite Radar and GPS Measurements[J]. Bull Seism Soc Am, 2002, 92(4): 1 377-1 389
[14] Pedersen R, Jonsson S, Arnadottir T, et al. Fault Slip Distribution of Two June 2000 Mw 6.5 Earthquake in South Iceland Estimated from Joint Inversion of InSAR and GPS Measurements[J]. Earth and Planetary Science Letters, 2003, 213: 487-502
[15] Wang Leyang,Xu Caijun,Wen Yangmao. Fault Parameters of 2008 Qinghai Dachaidan Mw 6.3 Earthquake 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)
[16] Zhang Peizhen. Current Tectonic Deformation, Strain Distribution and Deep Dynamic Process of Eastern Margin of Qinghai-Tibet Plateau in Western Sichuan[J]. Science China: Earth Sciences, 2008, 38(9):1 041-1 056(张培震. 青藏高原东缘川西的现今构造变形、应变分配与深部动力过程[J]. 中国科学D辑:地球科学,2008, 38(9):1 041-1 056)
[17] Xu X W, Wen X Z, Yu G H, et al.Coseismic Reverse- and Oblique-Slip Surface Faulting Generated by the 2008 Mw 7.9 Wenchuan Earthquake, China[J]. Geology, 2009, 37: 515-518
[18] Zhang P, Wen X, Shen Z, et al. Oblique, High-Angle, Listric-Reserve Faulting and Associated Development of Strain: The Wenchuan Earthquake of May 12, 2008, Sichuan, China[J]. Annu Rev Earth Planet Sci, 2010, 38: 353-382
[19] Xu Caijun, Yin Zhi. Progress in Inversion for Tectonic Stress-Strain Fields Using Geodetic Data[J]. Geomatics and Information Science of Wuhan University, 2014,39(10):1 135-1 146(许才军,尹智. 利用大地测量资料反演构造应力应变场研究进展[J].武汉大学学报·信息科学版, 2014, 39(10):1 135-1 146
[20] 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): 1 135-1 154
[21] Okada Y. Internal Deformation due to Shear and Tensile Faults in a Half-Space[J]. Bulletin of the Seismological Society of America,1992,82(2): 1 018-1 140
[22] Funning G J, Parsons B, Wright T J, et al. Surface Displacements and Source Parameters of the 2003 Bam (Iran) Earthquake from Envisat Advanced Synthetic Aperture Radar Imagery[J]. Journal of Geophysical Research, 2005, 110(B09): 406-411