2008年3月21日新疆于田7.1级地震近断层破坏作用
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摘要
2008年3月21日新疆于田7.1级地震发生在青藏高原北缘东昆仑山、西昆仑山和阿尔金山交汇的地区。文中介绍了此次地震的近断层破坏作用。此次地震在阿尔金断裂西端近南北向谷地海拔4 900~5 600m东坡形成了近31km长的地震地表破裂带。破裂带主要显示正断层滑动性质,其总体走向近南北,但局部追索北北西和北北东向共轭断裂发育,走向变化很大。受地形及滑塌作用影响,断裂陡坎高度最大可达20m,垂直位移为2m左右,最大水平拉张量也接近1.8m,此外局部还存在近1m的左旋位移。沿断裂发育一个近10hm2的滑坡体,以及大量中小规模的滑坡、崩塌,多为冰碛物、洪积物及残坡积物等松散堆积。虽位于陡峭的山坡上,也未见大规模基岩崩塌、滑坡。通过平地上巨石的翻滚推测,断层附近的最大加速度峰值可达1 g。同时根据不同坡度的边坡崩塌和滚石发育程度估算出距离断层不同距离地区的地震震动峰值加速度。地裂缝分布范围较宽,距断层1km的地区仍可见到长度超过100m的地裂缝。这些地裂缝可能是地震震动、谷地边坡变形及旁支断层地震触发滑动的综合产物。极震区最大烈度估计可达Ⅹ度,综合各方面资料文章提供了该次地震Ⅸ度、Ⅷ度、和Ⅶ度等震线;长轴方向呈NNE-SSW向,与余震方向大致一致。近断层破坏作用包括强地面运动、断层破裂带、地裂缝、滑坡、崩塌、滚石等。它们受到震级、断裂活动性质及场地条件等多因素控制。
The near-fault damaging effects of 2008Yutian MS7.1earthquake in Xinjiang,China were investigated in May of 2011.This quake occurred at the junction of West Kunlun,East Kunlun and Altun Tag Mountains in the north margin of Tibetan Plateau.The characteristics of near fault damaging effects of this quake are introduced in this paper.After the earthquake,a 31km long surface rupture appeared along the eastern slope of a N-S trending valley with the elevation of 4900-5600m,developed in the western end of the Altun Tag fault.The general trending of the rupture is in N-S,but locally it extends following the conjugate breaks of NNE-NNW and varies greatly in trending.Due to the topography and slumping,the maximun height of the fault scarp on the steep slope is up to 20m.The largest vertical offset of the rupture is about 2m,and the maximum horizontal extension is about 1.8m.Besides,there are locally about 1msinistral displacements.A large landslide with area over 10hm2,as well as a large number of moderate and small landslides and collapses were developed during the quake in loose debris,including moraine,diluvial,and eluvial deposits,which can be seen along the surface ruptures on the mountainside.No large scale bedrock collapse or landslide was found,even on the steep slopes along the rupture.The peak acceleration of strong ground motion,inferred from the evidence of rolled or turned over of large boulders on the level ground,is up to 1 g.Based on the collapse of slopes and the development of large boulders,the peak acceleration values of the strong ground motion at various distance from the fault can be calculated.The distribution of the surface cracks is rather wide,and about 1km from the the fault,the surface cracks more than 100mlong still can be found.These cracks are probably the integrated results of earthquake tremor,valley slope deformation and quake-induced sliding of the branch faults.The maximum intensity of extreme seismic zone of this quake is estimated to beⅩdegree in Chinese Seismic Intensity Scale.The isoseismic lines of Ⅸ,Ⅷ,Ⅶ degrees were inferred from comprehensive observed data or phenomena.The long axis of the intensity district is trending to NNE-SSW,which is consistent with the distribution of aftershocks.The near-fault damage effects involved strong ground motion,fault ruptures,fissures,landslides,collapses,and rock falls.They were controlled by the magnitude and slip sense of the quake,and the site condition of the epicenter.
The near-fault damaging effects of 2008Yutian MS7.1earthquake in Xinjiang,China were investigated in May of 2011.This quake occurred at the junction of West Kunlun,East Kunlun and Altun Tag Mountains in the north margin of Tibetan Plateau.The characteristics of near fault damaging effects of this quake are introduced in this paper.After the earthquake,a 31km long surface rupture appeared along the eastern slope of a N-S trending valley with the elevation of 4900-5600m,developed in the western end of the Altun Tag fault.The general trending of the rupture is in N-S,but locally it extends following the conjugate breaks of NNE-NNW and varies greatly in trending.Due to the topography and slumping,the maximun height of the fault scarp on the steep slope is up to 20m.The largest vertical offset of the rupture is about 2m,and the maximum horizontal extension is about 1.8m.Besides,there are locally about 1msinistral displacements.A large landslide with area over 10hm2,as well as a large number of moderate and small landslides and collapses were developed during the quake in loose debris,including moraine,diluvial,and eluvial deposits,which can be seen along the surface ruptures on the mountainside.No large scale bedrock collapse or landslide was found,even on the steep slopes along the rupture.The peak acceleration of strong ground motion,inferred from the evidence of rolled or turned over of large boulders on the level ground,is up to 1 g.Based on the collapse of slopes and the development of large boulders,the peak acceleration values of the strong ground motion at various distance from the fault can be calculated.The distribution of the surface cracks is rather wide,and about 1km from the the fault,the surface cracks more than 100mlong still can be found.These cracks are probably the integrated results of earthquake tremor,valley slope deformation and quake-induced sliding of the branch faults.The maximum intensity of extreme seismic zone of this quake is estimated to beⅩdegree in Chinese Seismic Intensity Scale.The isoseismic lines of Ⅸ,Ⅷ,Ⅶ degrees were inferred from comprehensive observed data or phenomena.The long axis of the intensity district is trending to NNE-SSW,which is consistent with the distribution of aftershocks.The near-fault damage effects involved strong ground motion,fault ruptures,fissures,landslides,collapses,and rock falls.They were controlled by the magnitude and slip sense of the quake,and the site condition of the epicenter.
引文
[1]陈学忠,蒋长胜,李燕娥.2008年3月21日新疆于田7.3级地震[J].国际地震动态,2008(4):18-28.
[2]唐明帅,王海涛,段天山.利用和田地震台阵数据对2008年于田7.3级地震序列重新定位[J].内陆地震,2010,24(3):227-235.
[3]尹光华,蒋靖祥,吴国栋,等.2008年3月21日于田7.3级地震构造背景[J].内陆地震,2008,31(4):343-349.
[4]Shan X,Zhang G,Wang C,et al.Source characteristics of the Yutian earthquake in 2008from inversion of the co-seismic deformation field mapped by InSAR[J].Journal of Asian Earth Sciences,2011,40(4):797-1026.
[5]聂晓红,李莹甄.2008年3月21日新疆于田7.4级地震序列特征及震前部分地震学异常特征[J].内陆地震,2010,24(4):330-339.
[6]邓起东,张培震,冉勇康,等.中国活动构造与地震活动[J].地学前缘,2003,10(增刊):66-73.
[7]陈运泰,许力生.青藏高原及其周边地区大地震震源过程成像[J].地学前缘,2003,10(1):57-62.
[8]任金卫,王敏.GPS观测的2001年昆仑山口西MS8.1级地震地壳变形[J].第四纪研究,2003,25(1):35-44.
[9]徐锡伟,Tapponnier P,van der Woerd J,等.阿尔金断裂带晚第四纪左旋走滑速率及其构造运动转换模式讨论[J].中国科学:D辑,2003,33(10):968-974.
[10]傅碧宏,张松林,谢小平,等.阿尔金断裂系西段—康西瓦断裂的晚第四纪构造地貌特征研究[J].第四纪研究,2006,26(2):228-235.
[11]Lin A,Kano K,Guo J,et al.Late Quaternary activity and dextral strike-slip movement on the Karakax Fault Zone,northwest Tibet[J].Tectonophysics,2008,453:44-62.
[12]鲁如魁,张国伟,钟华明,等.从郭扎错断裂构造特征探讨阿尔金断裂带西延问题[J].中国地质,2007,34(2):229-239.
[13]洪顺英,申旭辉,单新健,等.基于升降轨ASAR的于田MS7.3级地震同震形变场信息提取与分析[J].国土资源遥感,2010(4):98-102.
[14]Xu X,Tan X,Yu G,et al.Normal-and oblique-slip of the2008Yutian earthquake:Evidence for eastward block motion,northern Tibetan Plateau[J].Tectonophysics,2013,584:152-165.
[15]国家地震局《阿尔金活动断裂》课题组.阿尔金活动断裂带[M].北京:地震出版社,1992:1-319.
[16]Ding G,Chen J,Tian Q J,et al.Active faults and magnitudes of left-lateral displacement along the northern margin of the Tibetan Plateau[J].Tectonophysics,2004,380:243-260.
[17]Zhao J,Mooney W D,Zhang X,et al.Crustal structure across the Altyn Tagh Range at the northern margin of the Tibetan plateau and tectonic implications[J].Earth and Planetary Science Letters,2006,241:804-814.
[18]徐锡伟,谭锡斌,吴国栋,等.2008年于田MS7.3地震地表破裂带特征及其构造属性讨论[J].地震地质,2011,33(2):462-471.
[19]韩金良,吴树仁,何淑军,等.5·12汶川8级地震次生地质灾害的基本特征及其形成机制浅析[J].地学前缘,2009,16(3):309-316.
[20]郭兆成,周成虎,孙晓宇,等.汶川地震触发崩滑地质灾害空间分布及影响因素[J].地学前缘,2010,17(5):234-242.
[21]袁仁茂,谭锡斌,陈桂华,等.地震破裂带特殊部位大型滑坡及其基于构造地貌发生模型的机制解释:以东河口抛射型滑坡为例[J].地学前缘,2010,17(5):243-253.
[22]GB 18306—2011中国地震动参数区划图[S].
[23]许向宁,王兰生.地震导致山体变形破裂机制地质力学模拟试验研究[J].地学前缘,2009,16(3):333-340.
[24]邓起东,高翔,陈桂华,等.青藏高原昆仑—汶川地震系列与巴颜喀喇断块的最新活动[J].地学前缘,2010,17(5):163-177.
[25]李德威.东昆仑、玉树、汶川地震的发生规律和形成机理:兼论大陆地震成因与预测[J].地学前缘,2010,17(5):179-191.
[26]徐锡伟,陈文彬,于贵华,等.2001年11月14日昆仑山库赛湖地震(MS8.1)地表破裂带的基本特征[J].地震地质,2002,24(1):1-13.
[27]朱艾斓,徐锡伟,于贵华,等.玉树地震序列重新定位及其地震构造研究[J].地学前缘,2012,19(4):8-14.
①新疆维吾尔自治区地震局、中国地震局联合现场工作队.2008年3月21日于田—策勒7.3级地震科学考察初步报告,2008.
[2]唐明帅,王海涛,段天山.利用和田地震台阵数据对2008年于田7.3级地震序列重新定位[J].内陆地震,2010,24(3):227-235.
[3]尹光华,蒋靖祥,吴国栋,等.2008年3月21日于田7.3级地震构造背景[J].内陆地震,2008,31(4):343-349.
[4]Shan X,Zhang G,Wang C,et al.Source characteristics of the Yutian earthquake in 2008from inversion of the co-seismic deformation field mapped by InSAR[J].Journal of Asian Earth Sciences,2011,40(4):797-1026.
[5]聂晓红,李莹甄.2008年3月21日新疆于田7.4级地震序列特征及震前部分地震学异常特征[J].内陆地震,2010,24(4):330-339.
[6]邓起东,张培震,冉勇康,等.中国活动构造与地震活动[J].地学前缘,2003,10(增刊):66-73.
[7]陈运泰,许力生.青藏高原及其周边地区大地震震源过程成像[J].地学前缘,2003,10(1):57-62.
[8]任金卫,王敏.GPS观测的2001年昆仑山口西MS8.1级地震地壳变形[J].第四纪研究,2003,25(1):35-44.
[9]徐锡伟,Tapponnier P,van der Woerd J,等.阿尔金断裂带晚第四纪左旋走滑速率及其构造运动转换模式讨论[J].中国科学:D辑,2003,33(10):968-974.
[10]傅碧宏,张松林,谢小平,等.阿尔金断裂系西段—康西瓦断裂的晚第四纪构造地貌特征研究[J].第四纪研究,2006,26(2):228-235.
[11]Lin A,Kano K,Guo J,et al.Late Quaternary activity and dextral strike-slip movement on the Karakax Fault Zone,northwest Tibet[J].Tectonophysics,2008,453:44-62.
[12]鲁如魁,张国伟,钟华明,等.从郭扎错断裂构造特征探讨阿尔金断裂带西延问题[J].中国地质,2007,34(2):229-239.
[13]洪顺英,申旭辉,单新健,等.基于升降轨ASAR的于田MS7.3级地震同震形变场信息提取与分析[J].国土资源遥感,2010(4):98-102.
[14]Xu X,Tan X,Yu G,et al.Normal-and oblique-slip of the2008Yutian earthquake:Evidence for eastward block motion,northern Tibetan Plateau[J].Tectonophysics,2013,584:152-165.
[15]国家地震局《阿尔金活动断裂》课题组.阿尔金活动断裂带[M].北京:地震出版社,1992:1-319.
[16]Ding G,Chen J,Tian Q J,et al.Active faults and magnitudes of left-lateral displacement along the northern margin of the Tibetan Plateau[J].Tectonophysics,2004,380:243-260.
[17]Zhao J,Mooney W D,Zhang X,et al.Crustal structure across the Altyn Tagh Range at the northern margin of the Tibetan plateau and tectonic implications[J].Earth and Planetary Science Letters,2006,241:804-814.
[18]徐锡伟,谭锡斌,吴国栋,等.2008年于田MS7.3地震地表破裂带特征及其构造属性讨论[J].地震地质,2011,33(2):462-471.
[19]韩金良,吴树仁,何淑军,等.5·12汶川8级地震次生地质灾害的基本特征及其形成机制浅析[J].地学前缘,2009,16(3):309-316.
[20]郭兆成,周成虎,孙晓宇,等.汶川地震触发崩滑地质灾害空间分布及影响因素[J].地学前缘,2010,17(5):234-242.
[21]袁仁茂,谭锡斌,陈桂华,等.地震破裂带特殊部位大型滑坡及其基于构造地貌发生模型的机制解释:以东河口抛射型滑坡为例[J].地学前缘,2010,17(5):243-253.
[22]GB 18306—2011中国地震动参数区划图[S].
[23]许向宁,王兰生.地震导致山体变形破裂机制地质力学模拟试验研究[J].地学前缘,2009,16(3):333-340.
[24]邓起东,高翔,陈桂华,等.青藏高原昆仑—汶川地震系列与巴颜喀喇断块的最新活动[J].地学前缘,2010,17(5):163-177.
[25]李德威.东昆仑、玉树、汶川地震的发生规律和形成机理:兼论大陆地震成因与预测[J].地学前缘,2010,17(5):179-191.
[26]徐锡伟,陈文彬,于贵华,等.2001年11月14日昆仑山库赛湖地震(MS8.1)地表破裂带的基本特征[J].地震地质,2002,24(1):1-13.
[27]朱艾斓,徐锡伟,于贵华,等.玉树地震序列重新定位及其地震构造研究[J].地学前缘,2012,19(4):8-14.
①新疆维吾尔自治区地震局、中国地震局联合现场工作队.2008年3月21日于田—策勒7.3级地震科学考察初步报告,2008.
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