2008年汶川M_S8.0地震多断裂破裂的近地表同震滑移及滑移分解
|
摘要
为深入理解汶川地震破裂的构造运动机制,本文选取典型的观测点,利用多种地质地貌标志测绘分析得到了汶川M_s8.0地震发震断裂的近地表三维同震滑移矢量.结果显示,北川映秀断裂上的白水河—高川破裂段北西盘沿88°方位角水平滑移2.58 m、垂直滑移3.70 m;安县—灌县断裂上的白鹿汉旺破裂北西盘沿134°方位角水平滑移1.63 m,垂直滑移2.00m;小鱼洞破裂带南西盘沿76°～79°方位角水平滑移2.15～2.71 m,垂直滑移1.36～1.51 m.平行的白水河高川破裂段和白鹿—汉旺破裂段合计形成1.72 m右旋走滑和3.49 m垂直断裂带的NW向水平缩短,总滑移方向(106°)与断裂带整体走向(42°)呈64°夹角,整个龙门山推覆构造带处于斜向挤压的构造环境.结合震源过程反演成果的分析显示,斜滑的白水河高川破裂段和逆冲型白鹿汉旺破裂段可能是在汶川地震中最大的一次子事件过程以滑移分解的形式而同时破裂形成的,滑移分解作用使两条断裂以斜滑与逆冲组合的力学性质产生破裂而非相同性质的斜滑破裂.小鱼洞破裂以低角度斜滑为主,可能是安县灌县断裂与北川映秀断裂以滑移分解形式同时破裂的纽带.小鱼洞断裂是龙门山断裂带长期处于斜向挤压的构造环境的产物,不只是逆冲断裂系中的捩断层.
In order to study the kinematical mechanism of the co-seismic rupture of the 2008 Wenchuan earthquake,we implemented a detailed surveying and mapping in some typical sites with geological and geomorphologic marks,and calculated the three dimension slip vectors.The northwestern hanging wall of Baishuihe-Gaochuan rupture associated with the Beichuan-Yingxiu fault slipped in an azimuth of 88°,with 2.58 m of horizontal slip and 3.70 m of vertical slip;The northwestern hanging wall of Bailu-Hanwang rupture associated with the Anxian-Guanxian fault slipped in an azimuth of 134°,with 1.63 m of horizontal slip and 2.00 m of vertical slip;The southwestern hanging wall of Xiaoyudong rupture slipped with an azimuth of 76° ～ 79°,2.15～ 2.71 m of horizontal slip and 1.36～1.51 m of vertical slip.There are totally about 1.72 m of strike slip and 3.49m of horizontal shortening perpendicular to the fault zone from the paralleling Baishuihe-Gaochuan and Bailu-hanwang ruptures.The integrated slip vector (trending 106°) has an angle of 64° with the fault zone (trending 42°) ,and the Longmenshan fault zone was under a transpression.Combining the result from source inversions,we propose that the oblique-slipping Baishuihe-Gaochuan rupture and the dip-slipping Bailu-Hanwang rupture were produced in the same time during the largest sub-event with a slip partitioning,and the mechanism of slip partitioning made the two faults ruptured with an oblique slip and a dip slip,but not all the same oblique slip.The Xiaoyudong rupture slipped in a relatively small dip angle,which acted as a trigger structure for the simultaneous rupture of Beichuan-Yingxiu fault and Anxian-Guanxian fault in a manner of slip partitioning.The Xiaoyudong fault was the production of the Longmenshan fault zone under the transpressional tectonics in a long term,not only a tear fault among the thrust system.
In order to study the kinematical mechanism of the co-seismic rupture of the 2008 Wenchuan earthquake,we implemented a detailed surveying and mapping in some typical sites with geological and geomorphologic marks,and calculated the three dimension slip vectors.The northwestern hanging wall of Baishuihe-Gaochuan rupture associated with the Beichuan-Yingxiu fault slipped in an azimuth of 88°,with 2.58 m of horizontal slip and 3.70 m of vertical slip;The northwestern hanging wall of Bailu-Hanwang rupture associated with the Anxian-Guanxian fault slipped in an azimuth of 134°,with 1.63 m of horizontal slip and 2.00 m of vertical slip;The southwestern hanging wall of Xiaoyudong rupture slipped with an azimuth of 76° ～ 79°,2.15～ 2.71 m of horizontal slip and 1.36～1.51 m of vertical slip.There are totally about 1.72 m of strike slip and 3.49m of horizontal shortening perpendicular to the fault zone from the paralleling Baishuihe-Gaochuan and Bailu-hanwang ruptures.The integrated slip vector (trending 106°) has an angle of 64° with the fault zone (trending 42°) ,and the Longmenshan fault zone was under a transpression.Combining the result from source inversions,we propose that the oblique-slipping Baishuihe-Gaochuan rupture and the dip-slipping Bailu-Hanwang rupture were produced in the same time during the largest sub-event with a slip partitioning,and the mechanism of slip partitioning made the two faults ruptured with an oblique slip and a dip slip,but not all the same oblique slip.The Xiaoyudong rupture slipped in a relatively small dip angle,which acted as a trigger structure for the simultaneous rupture of Beichuan-Yingxiu fault and Anxian-Guanxian fault in a manner of slip partitioning.The Xiaoyudong fault was the production of the Longmenshan fault zone under the transpressional tectonics in a long term,not only a tear fault among the thrust system.
引文
[1] 徐锡伟,闻学泽,叶建青等.汶川M_S8． 0地震地表破裂带及其发震构造.地震地质,2008,30(3) :597～629 Xu X W, Wen X Z, Ye J Q, et al. The M_s8． 0 Wenchuan earthquake surface ruptures and its seismogenic structure.Seismology and Geology (in Chinese) ,2008,30(3) : 597 ～ 629
[ 2 ] Xu X W, Wen X Z, Yu G H, et al. Co-seismic reverse-and oblique-slip surface faulting generated by the 2008 M_w7． 9 Wenchuan earthquake. China. Geology, 2009 , 37(6) : 515 ～518
[3] 朱艾斓,徐锡伟,刁桂苓等.汶川M_s8． 0地震部分余震重新定位及地震构造初步分析.地震地质,2008,30(3) :759～767 Zhu A L, Xu X W, Diao G L, et al. Relocation of the M_S8． 0 Wenchuan earthquake sequence in part: preliminary seismotectonic analysis. Seismology and Geology ( in Chinese), 2008,30(3) :759～767
[4] 黄媛,吴建平,张天中等.汶川8． 0级大地震及其余震序列重定位研究.中国科学(D辑:地球科学),2008,(10) :1242～1249 Huang Y, Wu J P, Zhang T Z, et al. Relocation of the M8． 0 Wenchuan earthquake and its aftershock sequence. Science in China Series D : Earth Sciences ,2008,51(12) : 1703 ～ 1711
[5] 陈九辉,刘启元,李顺成等.汶川M_S8． 0地震余震序列重新定位及其地震构造研究.地球物理学报,2009,52(2) :390～397 Chen J H, Liu Q Y, Li S C, et al. Seismotectonic study by relocation of the Wenchuan M_S8． 0 earthquake sequence. Chinese J. Geophys. (in Chinese) ,2009 ,52(2) : 390 ～397
[6] 张勇,冯万鹏,许力生等.2008年汶川大地震的时空破裂过程.中国科学(D辑:地球科学),2008,38(10) :1186～1194 Zhang Y, Feng W P, Xu L S, et al. Spatio-temporal rupture process of the 2008 great Wenchuan earthquake. Science in ChinaiSeries D-Earth Sciences) ,2009 ,52(2) : 145 ～154
[7] 王卫民,赵连锋,李娟等.四川汶川8． 0级地震震源过程.地球物理学报,2008,51(5) :1403～1410
Wang W M, Zhao L F, Li J, et al. Rupture process of the M_s8． 0 wenchuan earthquake of Sichuan, China. Chinese J. Geophys. (in Chinese) ,51(5) :1403 ～1410
[8] 胡幸平,俞春泉,陶开等.利用P波初动资料求解汶川地震及其强余震震源机制解.地球物理学报。2008,51(6) :1711～1718 Hu X P,Yu C Q,Tao K, et al. Focal mechanism solutions of Wenchuan earthquake and its strong aftershocks obtained from initial P wave polarity analysis. Chinese J .Geophys. (in Chinese),2008,51(6) :1711～1718
[9] 孙建宝,梁芳,沈正康等.汶川M_s8． 0地震InSAR形变观测及初步分析.地震地质,2008,30(3) :789～795
Sun J B, Liang F, Shen Z K, et al. Insar deformation observation and preliminary analysis of the M_s8 Wenchuan earthquake. Seismology and Geology (in Chinese) , 30 (3) : 789 ～ 795
[10] 国家重大科学工程中国地壳运动观测网络项目组.GPS测定的2008年汶川M_s8． 0级地震的同震位移场.中国科学(D辑:地球科学),2008,38(10) :1195～1206 GUO-Jia-Zhong-Da-Ke-Xue-Gong-Cheng“Zhong-Guo-Di-Ke-Yun-Dong-Guan-Ce-Wang-Luo”Xiang-Mu-Zu. Strain field of the M_s8． 0 2008 Wenchuan earthquake from GPS. Science in China (Series D-Earth Sciences) (in Chinese), 2008,38(10) : 1195 ～ 1206
[11] 滕吉文,白登海,杨辉等.2008汶川M_s8． 0地震发生的深层过程和动力学响应.地球物理学报,2008,51(5) :1385～1402 Teng J W, Bai D H, Yang H, et al. Deep processes and dynamic responses associated with the Wenchuan M_s8． 0 earthquake of 2008． Chinese J. Geophys. (in Chinese) ,2008, 51(5) : 1385 ～ 1402
[12] 刘启元,李昱,陈九辉等.汶川M_S8． 0地震:地壳上地幔S波速度结构的初步研究.地球物理学报,2009,52(2) :309～319 Liu Q Y, Li Y, Chen J H, et al. Wenchuan M_s 8． 0 earthquake: preliminary study of the S-wave velocity structure of the crust and upper mantle. Chinese J. Geophys. (in Chinese),2009,52(2) :309 ～ 319
[13] Xu X W, Yu G H, Klinger Y, et al. Reevaluation of surface rupture parameters and faulting segmentation of the 2001 Kunlunshan earthquake (M_w7． 8) , northern Tibetan Plateau,China. Journal of Geophysical Research-Solid Earth ,2006,UKB5) , Doi 10． 1029/2004jb003488
[14] 陈桂华,李峰,郑荣章,等.逆冲型断裂同震地表变形定量分析的几个问题--以汶川M_S8． 0地震为例.地震地质,2008,30(3) :674～682 Chen G H, Li F , Zheng R Z, et al. Several issues in the quantitative analysis of co-seismic surface rupture produced by reversal faults: a case study from the 2008 wenchuan earthquake. Seismology and Geology (in Chinese) , 2008,30 (3) :674～682
[15] Lee J C, Rubin C, Mueller K, et al. , Quantitative analysis of movement along an earthquake thrust scarp: a case study of a vertical exposure of the 1999 surface rupture of the Chelungpu fault at Wufeng, western Taiwan. Journal of Asian Earth Sciences,2004,23(2) :263～273
[16] Angelier J, Lee J C, Hu J C, et al. Three-dimensional deformation along the rupture trace of the September 21st,1999, Taiwan earthquake: a case study in the Kuangfu school. Journal of Structural Geology , 2003,25 (3) : 351 ～370
[17] Angelier J, Lee J C, Chu H T, et al. Reconstruction of fault slip of the September 21st, 1999, Taiwan earthquake in the asphalted surface of a car, park, and co-seismic slip partitioning. Journal of Structural Geology , 2003, 25 (3) :345～350
[18] 杜义,谢富仁,张效亮等.汶川M_s8． 0级地震断层滑动机制研究.地球物理学报,2009,52(2) :464～473
Du Y, Xie F R, Zhang X L, et al. The mechanics of fault slip of M_S8． 0 Wenchuan earthquake. Chinese J. Geophys. (in Chinese), 2009,52(2) :464 ～473
[19] 冉勇康,陈立春,陈桂华等.汶川M_S8． 0地震发震断裂大地震原地重复现象初析.地震地质,2008,30(3) :630～643 Ran Y K, Chen L C, Chen G H, et al. Primary analyses of in-situ recurrence of large earthquake along seismogenic fault of the M_s8． 0 Wenchuan earthquake. Seismology and Geology (in Chinese), 2008,30(3) : 630 ～ 643
[20] Nishimura N, Yagi Y. Rupture Process for May 12, 2008 Sichuan Earthquake (Ver. 2) . 2008; http://www. geol.tsukuba. ac.jp/～nisimura/20080512/.
[21] 张勇,许力生,陈运泰.2008年汶川大地震震源机制的时空变化.地球物理学报,200,52(2) :379～389
Zhang Y, Xu L S, Chen Y T. Rupture process of the 2008 great Wenchuan earthquake from the analysis of the Alaska-array data. Chinese J. Geophys. (in Chinese) , 2009,52(2) : 379 ～ 389
[22] Li X J, Zhou Z H, Yu H Y, et al. Strong motion observations and recordings from the great Wenchuan Earthquake. Earthquake Engineering and Engineering Vibration,2008,7(3) :235～246
[23] Lettis W R, Hanson K L. Crustal strain partitioning:Implications for seismic-hazard assessment in western California. Geology, 1991,19(6) :559～562
[24] Bowman D, King G, Tapponnier P. Slip partitioning by elastoplastic propagation of oblique slip at depth. Science,2003,300(5622) :1121 ～1123
[25] Harris R A, Introduction to special section: Stress triggers,stress shadows, and implications for seismic hazard. J.Geophys. Res. ,1998,103:24347 ～ 24358
[26] Parsons T, Ji C, Kirby E. Stress changes from the 2008 Wenchuan e.arthquake and increased hazard in the Sichuan basin. Nature,2008,454(7203) :509 ～ 510
[ 2 ] Xu X W, Wen X Z, Yu G H, et al. Co-seismic reverse-and oblique-slip surface faulting generated by the 2008 M_w7． 9 Wenchuan earthquake. China. Geology, 2009 , 37(6) : 515 ～518
[3] 朱艾斓,徐锡伟,刁桂苓等.汶川M_s8． 0地震部分余震重新定位及地震构造初步分析.地震地质,2008,30(3) :759～767 Zhu A L, Xu X W, Diao G L, et al. Relocation of the M_S8． 0 Wenchuan earthquake sequence in part: preliminary seismotectonic analysis. Seismology and Geology ( in Chinese), 2008,30(3) :759～767
[4] 黄媛,吴建平,张天中等.汶川8． 0级大地震及其余震序列重定位研究.中国科学(D辑:地球科学),2008,(10) :1242～1249 Huang Y, Wu J P, Zhang T Z, et al. Relocation of the M8． 0 Wenchuan earthquake and its aftershock sequence. Science in China Series D : Earth Sciences ,2008,51(12) : 1703 ～ 1711
[5] 陈九辉,刘启元,李顺成等.汶川M_S8． 0地震余震序列重新定位及其地震构造研究.地球物理学报,2009,52(2) :390～397 Chen J H, Liu Q Y, Li S C, et al. Seismotectonic study by relocation of the Wenchuan M_S8． 0 earthquake sequence. Chinese J. Geophys. (in Chinese) ,2009 ,52(2) : 390 ～397
[6] 张勇,冯万鹏,许力生等.2008年汶川大地震的时空破裂过程.中国科学(D辑:地球科学),2008,38(10) :1186～1194 Zhang Y, Feng W P, Xu L S, et al. Spatio-temporal rupture process of the 2008 great Wenchuan earthquake. Science in ChinaiSeries D-Earth Sciences) ,2009 ,52(2) : 145 ～154
[7] 王卫民,赵连锋,李娟等.四川汶川8． 0级地震震源过程.地球物理学报,2008,51(5) :1403～1410
Wang W M, Zhao L F, Li J, et al. Rupture process of the M_s8． 0 wenchuan earthquake of Sichuan, China. Chinese J. Geophys. (in Chinese) ,51(5) :1403 ～1410
[8] 胡幸平,俞春泉,陶开等.利用P波初动资料求解汶川地震及其强余震震源机制解.地球物理学报。2008,51(6) :1711～1718 Hu X P,Yu C Q,Tao K, et al. Focal mechanism solutions of Wenchuan earthquake and its strong aftershocks obtained from initial P wave polarity analysis. Chinese J .Geophys. (in Chinese),2008,51(6) :1711～1718
[9] 孙建宝,梁芳,沈正康等.汶川M_s8． 0地震InSAR形变观测及初步分析.地震地质,2008,30(3) :789～795
Sun J B, Liang F, Shen Z K, et al. Insar deformation observation and preliminary analysis of the M_s8 Wenchuan earthquake. Seismology and Geology (in Chinese) , 30 (3) : 789 ～ 795
[10] 国家重大科学工程中国地壳运动观测网络项目组.GPS测定的2008年汶川M_s8． 0级地震的同震位移场.中国科学(D辑:地球科学),2008,38(10) :1195～1206 GUO-Jia-Zhong-Da-Ke-Xue-Gong-Cheng“Zhong-Guo-Di-Ke-Yun-Dong-Guan-Ce-Wang-Luo”Xiang-Mu-Zu. Strain field of the M_s8． 0 2008 Wenchuan earthquake from GPS. Science in China (Series D-Earth Sciences) (in Chinese), 2008,38(10) : 1195 ～ 1206
[11] 滕吉文,白登海,杨辉等.2008汶川M_s8． 0地震发生的深层过程和动力学响应.地球物理学报,2008,51(5) :1385～1402 Teng J W, Bai D H, Yang H, et al. Deep processes and dynamic responses associated with the Wenchuan M_s8． 0 earthquake of 2008． Chinese J. Geophys. (in Chinese) ,2008, 51(5) : 1385 ～ 1402
[12] 刘启元,李昱,陈九辉等.汶川M_S8． 0地震:地壳上地幔S波速度结构的初步研究.地球物理学报,2009,52(2) :309～319 Liu Q Y, Li Y, Chen J H, et al. Wenchuan M_s 8． 0 earthquake: preliminary study of the S-wave velocity structure of the crust and upper mantle. Chinese J. Geophys. (in Chinese),2009,52(2) :309 ～ 319
[13] Xu X W, Yu G H, Klinger Y, et al. Reevaluation of surface rupture parameters and faulting segmentation of the 2001 Kunlunshan earthquake (M_w7． 8) , northern Tibetan Plateau,China. Journal of Geophysical Research-Solid Earth ,2006,UKB5) , Doi 10． 1029/2004jb003488
[14] 陈桂华,李峰,郑荣章,等.逆冲型断裂同震地表变形定量分析的几个问题--以汶川M_S8． 0地震为例.地震地质,2008,30(3) :674～682 Chen G H, Li F , Zheng R Z, et al. Several issues in the quantitative analysis of co-seismic surface rupture produced by reversal faults: a case study from the 2008 wenchuan earthquake. Seismology and Geology (in Chinese) , 2008,30 (3) :674～682
[15] Lee J C, Rubin C, Mueller K, et al. , Quantitative analysis of movement along an earthquake thrust scarp: a case study of a vertical exposure of the 1999 surface rupture of the Chelungpu fault at Wufeng, western Taiwan. Journal of Asian Earth Sciences,2004,23(2) :263～273
[16] Angelier J, Lee J C, Hu J C, et al. Three-dimensional deformation along the rupture trace of the September 21st,1999, Taiwan earthquake: a case study in the Kuangfu school. Journal of Structural Geology , 2003,25 (3) : 351 ～370
[17] Angelier J, Lee J C, Chu H T, et al. Reconstruction of fault slip of the September 21st, 1999, Taiwan earthquake in the asphalted surface of a car, park, and co-seismic slip partitioning. Journal of Structural Geology , 2003, 25 (3) :345～350
[18] 杜义,谢富仁,张效亮等.汶川M_s8． 0级地震断层滑动机制研究.地球物理学报,2009,52(2) :464～473
Du Y, Xie F R, Zhang X L, et al. The mechanics of fault slip of M_S8． 0 Wenchuan earthquake. Chinese J. Geophys. (in Chinese), 2009,52(2) :464 ～473
[19] 冉勇康,陈立春,陈桂华等.汶川M_S8． 0地震发震断裂大地震原地重复现象初析.地震地质,2008,30(3) :630～643 Ran Y K, Chen L C, Chen G H, et al. Primary analyses of in-situ recurrence of large earthquake along seismogenic fault of the M_s8． 0 Wenchuan earthquake. Seismology and Geology (in Chinese), 2008,30(3) : 630 ～ 643
[20] Nishimura N, Yagi Y. Rupture Process for May 12, 2008 Sichuan Earthquake (Ver. 2) . 2008; http://www. geol.tsukuba. ac.jp/～nisimura/20080512/.
[21] 张勇,许力生,陈运泰.2008年汶川大地震震源机制的时空变化.地球物理学报,200,52(2) :379～389
Zhang Y, Xu L S, Chen Y T. Rupture process of the 2008 great Wenchuan earthquake from the analysis of the Alaska-array data. Chinese J. Geophys. (in Chinese) , 2009,52(2) : 379 ～ 389
[22] Li X J, Zhou Z H, Yu H Y, et al. Strong motion observations and recordings from the great Wenchuan Earthquake. Earthquake Engineering and Engineering Vibration,2008,7(3) :235～246
[23] Lettis W R, Hanson K L. Crustal strain partitioning:Implications for seismic-hazard assessment in western California. Geology, 1991,19(6) :559～562
[24] Bowman D, King G, Tapponnier P. Slip partitioning by elastoplastic propagation of oblique slip at depth. Science,2003,300(5622) :1121 ～1123
[25] Harris R A, Introduction to special section: Stress triggers,stress shadows, and implications for seismic hazard. J.Geophys. Res. ,1998,103:24347 ～ 24358
[26] Parsons T, Ji C, Kirby E. Stress changes from the 2008 Wenchuan e.arthquake and increased hazard in the Sichuan basin. Nature,2008,454(7203) :509 ～ 510
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