基于干涉雷达的玉树地震断裂运动模式与地震迁移趋势分析
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摘要
2010年4月14日青海省玉树县发生Ms7.1级地震。利用地震前后2期ALOS雷达数据进行了地表同震形变场InSAR解译研究,获取了高质量的干涉图像,并解算出定量变形场。进而根据干涉计算的变形方向、变形范围、变形量和变形梯度,参考该区的构造背景和走滑断裂的力学机理对本次地震构造活动进行了分析并得出如下结论:1)玉树地震引发了地表NWW走向、由5段构成的"S"形走滑断裂,总体为左阶排列,走滑量从10.2cm到133.2cm不等,走滑极值可达195cm,其中在结古镇和隆宝镇附近的两段出现较明显的地表破裂;2)断裂两侧的雷达视线向运动方向和运动量的差异预示发震断裂以左旋走滑运动为主,SW盘为主动盘;3)宏观震中可以定位于玉树县城西北约16km的地表陡变带附近;4)发震断裂地表行迹、变形量和地表破裂幅度预示余震将主要沿发震断裂向NW迁移;5)根据青藏高原东部地块的分区,本次地震属于羌塘地块活动的结果,与巴颜喀拉地块活动引发的汶川地震不存在直接的关联。
On April 14,2010,a Ms7.1 earthquake struck the Yushu County,Qinghai Province,China.The authors observed the co-seismic deformation of Yushu Ms7.1 scale earthquake,on July,14,2010,using two periods PALSAR by Interferometric Synthetic Aperture Radar(InSAR) technology,and yielding a clearly wrapped InSAR image and solving a absolutely deformation map covering most earthquake impact region.Furthermore,referencing to the amount,region,direction and gradient of InSAR co-seismic deformation,as well as combining with tectonic setting and mechanics of strike-slip fault,this paper infers its tectonic activity features: 1)Yushu earthquake triggered a NWW extend,sinistral step,"S" shape strike-slip fault deformation belt,which contains 5 sub-sections,average slip dislocation ranging from 10.2 cm to 133.2 cm,maximum up to 195 cm,and two of them near Jiegu Town and Longbao Town presented clear surface ruptures.2)The difference of two walls' movement in direction and amount shows that the seisgenic fault is a sinistral strike-slip and SW wall is an initiative wall.3)The macro-epicenter can be located on mutation belt of NW 16 km of Yushu County;4)The deformation amount,surface track and rupture amplitude of seisgenic fault indicate that the aftershocks will migrate towards NW alone fault.5)This earthquake is the results of Qiangtang Block's activity and does not directly related with Wenchuan Earthquake induced by Bayan Har Block.
On April 14,2010,a Ms7.1 earthquake struck the Yushu County,Qinghai Province,China.The authors observed the co-seismic deformation of Yushu Ms7.1 scale earthquake,on July,14,2010,using two periods PALSAR by Interferometric Synthetic Aperture Radar(InSAR) technology,and yielding a clearly wrapped InSAR image and solving a absolutely deformation map covering most earthquake impact region.Furthermore,referencing to the amount,region,direction and gradient of InSAR co-seismic deformation,as well as combining with tectonic setting and mechanics of strike-slip fault,this paper infers its tectonic activity features: 1)Yushu earthquake triggered a NWW extend,sinistral step,"S" shape strike-slip fault deformation belt,which contains 5 sub-sections,average slip dislocation ranging from 10.2 cm to 133.2 cm,maximum up to 195 cm,and two of them near Jiegu Town and Longbao Town presented clear surface ruptures.2)The difference of two walls' movement in direction and amount shows that the seisgenic fault is a sinistral strike-slip and SW wall is an initiative wall.3)The macro-epicenter can be located on mutation belt of NW 16 km of Yushu County;4)The deformation amount,surface track and rupture amplitude of seisgenic fault indicate that the aftershocks will migrate towards NW alone fault.5)This earthquake is the results of Qiangtang Block's activity and does not directly related with Wenchuan Earthquake induced by Bayan Har Block.
引文
[1]Zhang Yong-shuang,Yao Xin,Xiong Tan-yu,et al.Rapid Identification and Emergency Investigation ofSurface Rupturesand Geohazards Induced by theMs7.1Yushu Earthquake[J].Acta Geologica Sinica,2010,84(6):801-813.
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[5]周荣军,闻学泽,蔡长星,等.甘孜—玉树断裂带的近代地震与未来地震趋势估计[J].地震地质,1997,19(2):115-124.Zhou Rong-jun,Wen Xue-ze,Cai Chang-xing,et al.Recent Earthquakes and Assessment of SeismicTendency on the Ganzi-Yushu Fault Zone[J].Seismology and Geology,1997,19(2):115-124.
[6]Massonnet D,Rossi M,Carmona C,et al.The Displa-cement Field of the Landers Earthquake Mapped byRadar Interferometry[J].Nature,1993,36(4),138-142.
[7]张岳桥,杨农,施炜,等.青藏高原东缘新构造及其对汶川地震的控制作用[J].地质学报,2008,82(12):1668-1678.Zhang Yue-qiao,Yang Nong,Shi Wei,et al.Neotectonics of Eastern Tibet and Its Control on theWenchuan Earthquake[J].Acta Geologica Sinica,2008,82(12):1668-1678.
[8]嵇少丞,王茜,孙圣思,等.亚洲大陆逃逸构造与现今中国地震活动[J].地质学报,2008,82(12):1644-1667.Ji Shao-cheng,Wang Qian,Sun Sheng-si,et al.Continental Extrusion and Seismicity in China[J].Acta Geologica Sinica,2008,82(12):1644-1667.
[9]都昌庭,李文巧,刘宁,等.2006年青海玉树5.0、5.6、5.4级地震灾害损失及震害特点[J].震灾防御技术,2006,1(4):371-377.Du Chang-ting,Li Wen-qiao,Liu Ning,et al.Characterstics of Loss and Hazards of YushuEarthquakes with M=5.0,5.6and 5.4in QinghaiProvince,2006[J].Technology for EarthquakeDiasaster Prevention,2006,1(4):371-377.
[10]吕乐婷,陈圣波,车大为,等.D-InSAR原理及其数据处理流程[J].吉林大学学报:地球科学版,2008(增刊1):232-234.LüLe-ting,Chen Sheng-bo,Che Da-wei,et al.ThePrinciple and Data Processing Flow of InterferometrySynthetic Aperture Radar[J].Journal of JilinUniversity:Earth Science Edition,2008,38(Sup.1):232-234.
[11]闻学泽.四川西部鲜水河—安宁河—则木河断裂带的地震破裂分段特征[J].地震地质,2000,22(3):239-249.Wen Xue-ze.Character of Rupture Segmentation ofthe Xianshuiher-Anninghe-Zemuhe Fault Zone,Western Sichuan[J].Seismology and Geology,2000,22(3):239-249.
[12]吴树仁,胡道功,石玲,等.鄂西清江下游主要活动断层分段、分形与地震活动[J].长春科技大学学报,1999,29(3):272-278.Wu Shu-ren,Hu Dao-gong,Shi Ling,et al.Segmentation,Fractal Dimension and EarthquakeActivity of the Main Active Faults in the LowQingjiang River of Western Hubei Province[J].Journal of Changchun University of Science andTechnology,1999,29(3):272-278.
①姚鑫.汶川地震同震形变场差分干涉雷达监测及其在区域地壳稳定性研究中的应用.中国地质科学院地质力学研究所基本科研业务费项目结题报告,2010:10-14.
①中国地震局.青海玉树7.1级地震震区地震构造分析.2010,http://www.eq-igl.ac.cn/.
②冉勇康.甘孜—玉树断裂及历史大地震活动情简况.2010.
[2]姚鑫,张永双,杨农,等.玉树地震InSAR观测及初步分析[J].地质力学学报,2010,19(2):129-136.Yao Xin,Zhang Yong-shuang,Yang Nong,et al.D-InSAR Deformation Observation and PreliminaryAnalysis of the Ms7.1 Yushu Earthquake[J].Geological Geomechanics,2010,19(2):129-136.
[3]滕吉文,刘财,韩立国,等.汶川—映秀Ms8.0地震的介质破裂与深部物质运移的动力机制[J].吉林大学学报:地球科学版,2009(4):559-583.Teng Ji-wen,Liu Cai,Han Li-guo,et al.TheDynamical Mechanism for Medium Rapture andMotion of Deep Matler on Wenchuan-Yingxiu Ms8.0Earthquake,2008[J].Journal of Jilin University:Earth Science Edition,2009,39(4):559-583.
[4]Yao Xin,Zhang Yong-shuang,Dai Fu-chu,et al.Geoha-zard Distribution and Geological Activity of WenchuanEarthquake Surveyed by D-InSAR[C]//GeologicalActive:International Association for EngineeringGeology and Environment(IAEG)Congress 2010.[S.l.]:CRC Press,2010:871-880.
[5]周荣军,闻学泽,蔡长星,等.甘孜—玉树断裂带的近代地震与未来地震趋势估计[J].地震地质,1997,19(2):115-124.Zhou Rong-jun,Wen Xue-ze,Cai Chang-xing,et al.Recent Earthquakes and Assessment of SeismicTendency on the Ganzi-Yushu Fault Zone[J].Seismology and Geology,1997,19(2):115-124.
[6]Massonnet D,Rossi M,Carmona C,et al.The Displa-cement Field of the Landers Earthquake Mapped byRadar Interferometry[J].Nature,1993,36(4),138-142.
[7]张岳桥,杨农,施炜,等.青藏高原东缘新构造及其对汶川地震的控制作用[J].地质学报,2008,82(12):1668-1678.Zhang Yue-qiao,Yang Nong,Shi Wei,et al.Neotectonics of Eastern Tibet and Its Control on theWenchuan Earthquake[J].Acta Geologica Sinica,2008,82(12):1668-1678.
[8]嵇少丞,王茜,孙圣思,等.亚洲大陆逃逸构造与现今中国地震活动[J].地质学报,2008,82(12):1644-1667.Ji Shao-cheng,Wang Qian,Sun Sheng-si,et al.Continental Extrusion and Seismicity in China[J].Acta Geologica Sinica,2008,82(12):1644-1667.
[9]都昌庭,李文巧,刘宁,等.2006年青海玉树5.0、5.6、5.4级地震灾害损失及震害特点[J].震灾防御技术,2006,1(4):371-377.Du Chang-ting,Li Wen-qiao,Liu Ning,et al.Characterstics of Loss and Hazards of YushuEarthquakes with M=5.0,5.6and 5.4in QinghaiProvince,2006[J].Technology for EarthquakeDiasaster Prevention,2006,1(4):371-377.
[10]吕乐婷,陈圣波,车大为,等.D-InSAR原理及其数据处理流程[J].吉林大学学报:地球科学版,2008(增刊1):232-234.LüLe-ting,Chen Sheng-bo,Che Da-wei,et al.ThePrinciple and Data Processing Flow of InterferometrySynthetic Aperture Radar[J].Journal of JilinUniversity:Earth Science Edition,2008,38(Sup.1):232-234.
[11]闻学泽.四川西部鲜水河—安宁河—则木河断裂带的地震破裂分段特征[J].地震地质,2000,22(3):239-249.Wen Xue-ze.Character of Rupture Segmentation ofthe Xianshuiher-Anninghe-Zemuhe Fault Zone,Western Sichuan[J].Seismology and Geology,2000,22(3):239-249.
[12]吴树仁,胡道功,石玲,等.鄂西清江下游主要活动断层分段、分形与地震活动[J].长春科技大学学报,1999,29(3):272-278.Wu Shu-ren,Hu Dao-gong,Shi Ling,et al.Segmentation,Fractal Dimension and EarthquakeActivity of the Main Active Faults in the LowQingjiang River of Western Hubei Province[J].Journal of Changchun University of Science andTechnology,1999,29(3):272-278.
①姚鑫.汶川地震同震形变场差分干涉雷达监测及其在区域地壳稳定性研究中的应用.中国地质科学院地质力学研究所基本科研业务费项目结题报告,2010:10-14.
①中国地震局.青海玉树7.1级地震震区地震构造分析.2010,http://www.eq-igl.ac.cn/.
②冉勇康.甘孜—玉树断裂及历史大地震活动情简况.2010.
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