断层滑动分布和位错模型影响效应的显著性分析
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摘要
利用4种已有的汶川地震断层同震滑动分布模型,采用Okada经典弹性半空间位错模型和孙文科球形位错模型,分别计算了汶川地震同震位移场,并将计算结果与GPS实测位移场进行对比分析;最后采用二元方差分析的方法,研究了断层滑动分布和位错模型对同震位移场的显著性影响。结果表明,基于沈正康断层滑动分布模型由球形位错计算的同震位移场与GPS实测值吻合性最好,模拟结果的残差均值Δv珋为0.007 m,残差协方差阵的迹trΣ为0.006 m;在断层破裂附近,滑动因子和位错因子都引起较大的均方离差,最大值分别为S2A=7.170 16 m2,S2B=91.407 7 m2;滑动分布和位错模型的显著性影响呈现出不同的空间分布特征,具体表现为:滑动分布的显著性影响体现在近场区域,位错模型主要体现在远场区域。
The co-seismic displacement caused by Wenchuan earthquake( Ms8. 0) was calculated with four seismic slip models using half-space( Okada) and spherical dislocation theory( Shen et al),respectively,and the displacement field calculated and the observation result were compared. Statistical significance caused by fault slipping and dislocation models were analyzed using the method of two-factor variance. Results show that co-seismic displacements calculated by the spherical dislocation model is consistent with the observation results,the mean value of residual is 0. 007 m,and its trace is 0. 006 m. Near the fault rupture,both slipping factor and dislocation factor causing larger mean square deviation,the maximum is S2A= 7. 170 16 m2,S2B= 91. 407 7 m2,respectively. The significant influence of slipping distribution and dislocation model shows the characteristics of different space distribution,the former is embodied in the near field area,while dislocation model is mainly embodied in the far-field region.
The co-seismic displacement caused by Wenchuan earthquake( Ms8. 0) was calculated with four seismic slip models using half-space( Okada) and spherical dislocation theory( Shen et al),respectively,and the displacement field calculated and the observation result were compared. Statistical significance caused by fault slipping and dislocation models were analyzed using the method of two-factor variance. Results show that co-seismic displacements calculated by the spherical dislocation model is consistent with the observation results,the mean value of residual is 0. 007 m,and its trace is 0. 006 m. Near the fault rupture,both slipping factor and dislocation factor causing larger mean square deviation,the maximum is S2A= 7. 170 16 m2,S2B= 91. 407 7 m2,respectively. The significant influence of slipping distribution and dislocation model shows the characteristics of different space distribution,the former is embodied in the near field area,while dislocation model is mainly embodied in the far-field region.
引文
1 张培震,徐锡伟,闻学泽,等.2008年汶川8.0级地震发震断裂的滑动速率,复发周期和构造成因[J].地球物理学报,2008,51(4):1 066-1 073.(Zhang Peizhen,Xu Xiwei,Wen Xueze,et al.Slip rates and recurrence intervals of the Longmenshan active fault zone,and tectonic implications for the mechanism of the May 12 Wenchuan earthquake,2008,Sichuan,China[J].Chinese Journal of Geophysics,2008,51(4):1 066-1 073)
2 Burchfiel B C,Royden L H,Hilst R D,et al.A geological and geophysical context for the Wenchuan earthquake of 12May 2008,Sichuan,People’s Republic of China[J].GSA Today,2008,18(7):5.
3 张培震.GPS测定的2008年汶川Ms8.0地震的同震位移场[J].中国科学:D辑,2008,38(10):1 195-1 206.(Zhang Peizhen.China crustal observation network project,co-seismic displacements of the 2008 Wenchuan earthquake(Ms8.0)observed by GPS[J].Sci China,2008,38(10):1 195-1 206)
4 张国宏,屈春燕,汪驰升,等.基于GPS和In SAR反演汶川Mw7.9地震断层滑动分布[J].大地测量与地球动力学,2010,30(4).(Zhang Guohong,Qu Chunyan,Wang Chisheng,et al.Inversion of slip distribution of 2008 Wenchuan Mw7.9 earthquake constrained jointly by In SAR and GPS measurements[J].Journal of Geodesy and Geodynamics,2010,30(4))
5 Ji Chen,Hayes G.Preliminary result of the May 12,2008 Mw7 .9 eastern Sichuan[J].US Geol Surv Reston Va,2008.
6 王卫民,赵连锋,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(5):1 403-1 410.(Wang Weimin,Zhao Lianfeng,Li Juan,et al.Rupture process of the Ms 8.0 Wenchuan earthquake of Sichuan,China[J].Chin J Geophys,2008,51(5):1 403-1 410)
7 Diao F,Xiong X,Wang R,et al.Slip model of the 2008 Mw7 .9 Wenchuan(China)earthquake derived from co-seismic GPS data[J].Earth Planets and Space,2010,62(11):869.
8 Shen Z K,Sun J,Zhang P,et al.Slip maxima at fault junctions and rupturing of barriers during the 2008 Wenchuan earthquake[J].Nature Geoscience,2009,2(10):718-724.
9 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.
10 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):1 018-1 040.
11 Sun W,Okubo S.Effects of earth’s spherical curvature and radial heterogeneity in dislocation studies—for a point dislocation[J].Geophysical Research Letters,2002,29(12):461-464.
12 Sun W,Okubo S,Vaníek P.Global displacements caused by point dislocations in a realistic Earth model[J].Journal of Geophysical Research:Solid Earth(1978–2012),1996,101 (B4):8 561-8 577.
13 Sun W,Okubo S,Fu G,et al.General formulations of global co-seismic deformations caused by an arbitrary dislocation in a spherically symmetric earth model-applicable to deformed earth surface and space-fixed point[J].Geophysical Journal International,2009,177(3):817-833.
14 朱介寿.汶川地震的岩石圈深部结构与动力学背景[J].成都理工大学学报:自然科学版,2008,35(4):348-356 .(Zhu Jieshou.The Wenchuan earthquake occurrence background in deep structure and dynamics of lithosphere[J].Journal of Chengdu University of Technology:Science&Technology Edition,2008,35(4):348-356)
15 徐朝繁,潘纪顺,王夫运,等.龙门山及其邻近地区深部地球物理探测[J].大地测量与地球动力学,2008,28(6):31-37.(Xu Zhaofan,Pan Jishun,Wang Fuyun,et al.Deep geophysical exploration of Longmenshan and its adjacent[J].Journal of Geodesy and Geodynamics,2008,28(6):31-37)
16 Wang W,Sun W,Jiang Z.Comparison of fault models of the2008 Wenchuan earthquake(Ms8.0)and spatial distributions of co-seismic deformations[J].Tectonophysics,2010,491(1):85-95.
17 Fu G,Sun W.Surface co-seismic gravity changes caused by dislocations in a 3-D heterogeneous earth[J].Geophysical Journal International,2008,172(2):479-503.
18 吴建平,明跃红,王椿镛.川滇地区速度结构的区域地震波形反演研究[J].地球物理学报,2006,49(5).(Wu Jianping,Ming Yuehong,Wang Chunyong,et al.Regional wave for inversion for crustal and upper mantle velocity structure below Chuandian region[J].Chin J Geophys,2006,49(5))
19 Wang C Y,Han W B,Wu J P,et al.Crustal structure beneath the eastern margin of the Tibetan plateau and its tectonic implications[J].Journal of Geophysical Research:Solid Earth(1978–2012),2007,112(B7).
20 Fu G,Sun W.Effects of spatial distribution of fault slip on calculating co-seismic displacement:Case studies of the Chi-Chi earthquake(Mw7.6)and the Kunlun earthquake(Mw7.8)[J].Geophysical Research Letters,2004,31(21).
21 张永志,赵大江,王卫东.断层走滑不均匀性对地面变形的影响[J].地球物理学报,2009,52(8).(Zhang Yongzhi,Zhao Dajiang,Wang Weidong.Effects on the earth surface deformation by asymmetric strike slip on fault plane[J].Chin J Geophys,2009,52(8))
2 Burchfiel B C,Royden L H,Hilst R D,et al.A geological and geophysical context for the Wenchuan earthquake of 12May 2008,Sichuan,People’s Republic of China[J].GSA Today,2008,18(7):5.
3 张培震.GPS测定的2008年汶川Ms8.0地震的同震位移场[J].中国科学:D辑,2008,38(10):1 195-1 206.(Zhang Peizhen.China crustal observation network project,co-seismic displacements of the 2008 Wenchuan earthquake(Ms8.0)observed by GPS[J].Sci China,2008,38(10):1 195-1 206)
4 张国宏,屈春燕,汪驰升,等.基于GPS和In SAR反演汶川Mw7.9地震断层滑动分布[J].大地测量与地球动力学,2010,30(4).(Zhang Guohong,Qu Chunyan,Wang Chisheng,et al.Inversion of slip distribution of 2008 Wenchuan Mw7.9 earthquake constrained jointly by In SAR and GPS measurements[J].Journal of Geodesy and Geodynamics,2010,30(4))
5 Ji Chen,Hayes G.Preliminary result of the May 12,2008 Mw7 .9 eastern Sichuan[J].US Geol Surv Reston Va,2008.
6 王卫民,赵连锋,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(5):1 403-1 410.(Wang Weimin,Zhao Lianfeng,Li Juan,et al.Rupture process of the Ms 8.0 Wenchuan earthquake of Sichuan,China[J].Chin J Geophys,2008,51(5):1 403-1 410)
7 Diao F,Xiong X,Wang R,et al.Slip model of the 2008 Mw7 .9 Wenchuan(China)earthquake derived from co-seismic GPS data[J].Earth Planets and Space,2010,62(11):869.
8 Shen Z K,Sun J,Zhang P,et al.Slip maxima at fault junctions and rupturing of barriers during the 2008 Wenchuan earthquake[J].Nature Geoscience,2009,2(10):718-724.
9 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.
10 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):1 018-1 040.
11 Sun W,Okubo S.Effects of earth’s spherical curvature and radial heterogeneity in dislocation studies—for a point dislocation[J].Geophysical Research Letters,2002,29(12):461-464.
12 Sun W,Okubo S,Vaníek P.Global displacements caused by point dislocations in a realistic Earth model[J].Journal of Geophysical Research:Solid Earth(1978–2012),1996,101 (B4):8 561-8 577.
13 Sun W,Okubo S,Fu G,et al.General formulations of global co-seismic deformations caused by an arbitrary dislocation in a spherically symmetric earth model-applicable to deformed earth surface and space-fixed point[J].Geophysical Journal International,2009,177(3):817-833.
14 朱介寿.汶川地震的岩石圈深部结构与动力学背景[J].成都理工大学学报:自然科学版,2008,35(4):348-356 .(Zhu Jieshou.The Wenchuan earthquake occurrence background in deep structure and dynamics of lithosphere[J].Journal of Chengdu University of Technology:Science&Technology Edition,2008,35(4):348-356)
15 徐朝繁,潘纪顺,王夫运,等.龙门山及其邻近地区深部地球物理探测[J].大地测量与地球动力学,2008,28(6):31-37.(Xu Zhaofan,Pan Jishun,Wang Fuyun,et al.Deep geophysical exploration of Longmenshan and its adjacent[J].Journal of Geodesy and Geodynamics,2008,28(6):31-37)
16 Wang W,Sun W,Jiang Z.Comparison of fault models of the2008 Wenchuan earthquake(Ms8.0)and spatial distributions of co-seismic deformations[J].Tectonophysics,2010,491(1):85-95.
17 Fu G,Sun W.Surface co-seismic gravity changes caused by dislocations in a 3-D heterogeneous earth[J].Geophysical Journal International,2008,172(2):479-503.
18 吴建平,明跃红,王椿镛.川滇地区速度结构的区域地震波形反演研究[J].地球物理学报,2006,49(5).(Wu Jianping,Ming Yuehong,Wang Chunyong,et al.Regional wave for inversion for crustal and upper mantle velocity structure below Chuandian region[J].Chin J Geophys,2006,49(5))
19 Wang C Y,Han W B,Wu J P,et al.Crustal structure beneath the eastern margin of the Tibetan plateau and its tectonic implications[J].Journal of Geophysical Research:Solid Earth(1978–2012),2007,112(B7).
20 Fu G,Sun W.Effects of spatial distribution of fault slip on calculating co-seismic displacement:Case studies of the Chi-Chi earthquake(Mw7.6)and the Kunlun earthquake(Mw7.8)[J].Geophysical Research Letters,2004,31(21).
21 张永志,赵大江,王卫东.断层走滑不均匀性对地面变形的影响[J].地球物理学报,2009,52(8).(Zhang Yongzhi,Zhao Dajiang,Wang Weidong.Effects on the earth surface deformation by asymmetric strike slip on fault plane[J].Chin J Geophys,2009,52(8))
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