玉树震区地质灾害分布规律与发育特征
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摘要
2010年4月14日7时49分,青海省玉树县发生MS7.1级地震。玉树地震不仅造成大量房屋破坏与人员伤亡,同时引发了大量的崩塌、滑坡和山体裂缝,并且形成了大量的诸如泥石流、碎屑流等链生灾害隐患,造成玉树震区地质灾害分布规律与发育特征发生显著改变。通过现场调查与数据统计,对地震前后地质灾害分布规律与发育特征进行分析、研究。结果表明:玉树震区震前地质灾害呈零星点状分布,以泥石流、不稳定斜坡为主要地质灾害类型,规模以小型为主,形成时间主要集中于每年的5～7月。震后,玉树震区地质灾害数量显著增加,在宏观震中结古镇主震断裂穿越的巴曲两岸与结古镇北部山区以及扎曲南部山区,沿主震断裂呈面状集中分布,距离主震断裂较远或远离宏观震中的区域呈零星点状分布。地质灾害受玉树主震断裂控制明显,并受坡型、坡高与坡度的控制;地质灾害主要分布于距主震断裂2km以内的北盘区域,在坡型上主要分布于凸型与直线型坡,高程为3800～4000m内,坡度在25°～40°范围内,且以30°～35°范围内地质灾害最为发育;地震造成山体地表裂缝所形成的地质灾害隐患比较突出,大中型规模的地质灾害数量明显增加,危害程度显著增高;汛期地质灾害发育更加集中,并加剧冻融期地质灾害的孕育。
At 7: 49a.m.April 14 th 2010,a Ms 7.1 earthquake occurred in Yushu county,Qinghai province,China.The Yushu earthquake not only resulted in destruction of lots of buildings and plenty of casualty,but also brought lots of geo-hazards such as debris flows,rock falls,landslides and ground cracks.So it evidently changed the distribution regularity and development characteristics of the geohazards at the region.Based on field investigations and statistics,the distribution regularity and development characteristics of the geohazards before and after the earthquake are analyzed.The results show that the geohazards scatter in the area and take place from May to July every year.The main types of the geohazards were debris flows and unstable slopes,as well as the main small scale of geohazards before the Yushu earthquake;After the earthquake,the numbers of geohazards increased obviously, and the distribution of geohazards concentrated in the areas where the main faults cross the Valley of Baqu river, the mountain areas of northern Jiegu town and southern of Zhaqu river,and the geohazards distribute sporadically in the areas where far away from the main faults or macroscopic epicenter.The geohazards are controlled evidently not only by the main faults,but also by the shape,altitude and gradient of slopes.The geohazards mainly distributed in the area of within 2km away from north of the main faults,and on the bulgy shape slopes,altitude of 3800 ～ 4000m,and the gradient of 25° ～ 40°,focused on the gradient of 30° ～ 35°.The geohazards induced by the ground cracks in the mountains develop distinctly,and the numbers of large and middle scales of geohazards increase clearly,so that the harm of geohazards increase greatly.Especially,the geohazards took place more frequently in rain season,which accelerates the development of geohazards in freezing and thawing periods.
At 7: 49a.m.April 14 th 2010,a Ms 7.1 earthquake occurred in Yushu county,Qinghai province,China.The Yushu earthquake not only resulted in destruction of lots of buildings and plenty of casualty,but also brought lots of geo-hazards such as debris flows,rock falls,landslides and ground cracks.So it evidently changed the distribution regularity and development characteristics of the geohazards at the region.Based on field investigations and statistics,the distribution regularity and development characteristics of the geohazards before and after the earthquake are analyzed.The results show that the geohazards scatter in the area and take place from May to July every year.The main types of the geohazards were debris flows and unstable slopes,as well as the main small scale of geohazards before the Yushu earthquake;After the earthquake,the numbers of geohazards increased obviously, and the distribution of geohazards concentrated in the areas where the main faults cross the Valley of Baqu river, the mountain areas of northern Jiegu town and southern of Zhaqu river,and the geohazards distribute sporadically in the areas where far away from the main faults or macroscopic epicenter.The geohazards are controlled evidently not only by the main faults,but also by the shape,altitude and gradient of slopes.The geohazards mainly distributed in the area of within 2km away from north of the main faults,and on the bulgy shape slopes,altitude of 3800 ～ 4000m,and the gradient of 25° ～ 40°,focused on the gradient of 30° ～ 35°.The geohazards induced by the ground cracks in the mountains develop distinctly,and the numbers of large and middle scales of geohazards increase clearly,so that the harm of geohazards increase greatly.Especially,the geohazards took place more frequently in rain season,which accelerates the development of geohazards in freezing and thawing periods.
引文
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[11]郭小花,李小林,赵振,等.青海4.14玉树地震地质作用对地质环境影响分析[J].工程地质学报,2011,19(5):685～696.Guo Xiaohua,Li Xiaolin,Zhao Zhen,et al.Effects of 4.14Yushu earthquake in Qinghai on geological enviroment.Journal ofEngineering Geology,2011,19(5):685～696.
[12]闻学泽,徐锡伟,郑荣章,等.甘孜—玉树断裂的平均滑动速率与近代大地震破裂[J].中国科学,2003,33(增):199～208.Wen Xueze,Xu Xiwei,Zheng Rongzhang,et al.Average slip-rateand recent large earthquake ruptures along the Ganzi—Yushufault.Science in China,2003,33(S):199～208.
[13]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 Rongjun,Wen Xueze,Cai Changxing,et al.Recentearthquakes and assessment of seismic tendency on the GanziYushu fault zone.Seismology and Geology,1997,19(2):115～124.
[14]都昌庭,李文巧,卢宁,等.2006年青海玉树地震类型和发震构造分析[J].西北地震学报,2007,29(3):271～274.Du Changting,Li Wenqiao,Lu Ning,et al.Analysis on theseismic type and seimogenic structure of Yushu earthquake inQinghai province in 2006.Northwestern Seismological Journal,2007,29(3):271～274.
[15]赵家绪,李玉军,张力征,等.青海玉树“4.14”地震灾区地质灾害应急排查报告[R].2010.Zhao Jiaxu,Li Yujun,Zhang Lizheng,et al.UrgencyInvestigation Report of Geohazrad in 4.14 Yushu EarthquakeStroked Area,Qinghai Province.2010.
[2]Keefer DK.Landslides caused by earthquakes[J].GeologicalSociety of America Bulletin,1984,95:406～421.
[3]Dai Fuchu,Xu Chong,Yao Xin,et al.Spatial distribution oflandslides triggered by the 2008 MS 8.0 Wenchuan earthquake,China[J].Journal of Asian Earth Sciences,2011,40(4):883～895.
[4]殷跃平.汶川8级地震地质灾害研究[J].工程地质学报,2008,16(4):433～444.Yin Yueping.Research on the geo-hazards triggered by Wenchuanearthquake,Sichuan.Journal of Engineering Geology,2008,16(4):433～444.
[5]祁生文,许强,刘春玲,等.汶川地震极重灾区地质背景及次生斜坡灾害空间发育规律[J].工程地质学报,2009,17(1):39～49.Qi Shengwen,Xu Qiang,Liu Chunling,et al.Slope instabilitiesin the severest disaster areas of 5.12 Wenchuan earthquake.Journal of Engineering Geology,2009,17(1):39～49.
[6]黄润秋,裴向军,李天赋.汶川地震触发大光包巨型滑坡基本特征及形成机理分析[J].工程地质学报,2008,16(6):730～741.Huang Runqiu,Pei Xiangjun,Li Tianfu.Basic characteristic andformation mechanism of the largest scale landslide at dagungbaooccurred during the Wenchuan earthquake.Journal of EngineeringGeology,2008,16(6):730～741.
[7]黄润秋,李为乐.汶川大地震触发地质灾害的断层效应分析[J].工程地质学报,2009,17(1):19～28.Huang Runqiu,Li Weile.Fault effect analysis of geo-hazardtriggered by Wenchuan earthquake.Journal of EngineeringGeology,2009,17(1):19～28.
[8]许强,黄润秋.5.12汶川大地震诱发大型崩滑灾害动力特征初探[J].工程地质学报,2008,16(6):722～729.Xu Qiang,Huang Runqiu.Kinetics characteristics of largelandslides triggered by May 12th Wenchuan earthquake.Journal ofEngineering Geology,2008,16(6):722～729.
[9]张永双,马寅生,胡道功,等.玉树地震地表破裂调查与灾后重建避让选址研究[J].地质学报,2010,84(5):593～605.Zhang Yongshuang,Ma Yinsheng,Hu Daogong,et al.Investigation and research on the surface rupture of the Yushuearthqu ake and reconstruction site selection.Acta GeologicaSinica,2010,84(5):593～605.
[10]许冲,徐锡伟,戴福初,等.2010年4月14日玉树地震滑坡空间分布与控制变量分析[J].工程地质学报,2011,19(4):505～510.Xu Chong,Xu Xiwei,Dai Fuchu,et al.Analysis of spatialdistribution and controlling parameters of landslides triggered bythe April 14,2010 Yushu earthquake.Journal of EngineeringGeology,2011,19(4):505～510.
[11]郭小花,李小林,赵振,等.青海4.14玉树地震地质作用对地质环境影响分析[J].工程地质学报,2011,19(5):685～696.Guo Xiaohua,Li Xiaolin,Zhao Zhen,et al.Effects of 4.14Yushu earthquake in Qinghai on geological enviroment.Journal ofEngineering Geology,2011,19(5):685～696.
[12]闻学泽,徐锡伟,郑荣章,等.甘孜—玉树断裂的平均滑动速率与近代大地震破裂[J].中国科学,2003,33(增):199～208.Wen Xueze,Xu Xiwei,Zheng Rongzhang,et al.Average slip-rateand recent large earthquake ruptures along the Ganzi—Yushufault.Science in China,2003,33(S):199～208.
[13]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 Rongjun,Wen Xueze,Cai Changxing,et al.Recentearthquakes and assessment of seismic tendency on the GanziYushu fault zone.Seismology and Geology,1997,19(2):115～124.
[14]都昌庭,李文巧,卢宁,等.2006年青海玉树地震类型和发震构造分析[J].西北地震学报,2007,29(3):271～274.Du Changting,Li Wenqiao,Lu Ning,et al.Analysis on theseismic type and seimogenic structure of Yushu earthquake inQinghai province in 2006.Northwestern Seismological Journal,2007,29(3):271～274.
[15]赵家绪,李玉军,张力征,等.青海玉树“4.14”地震灾区地质灾害应急排查报告[R].2010.Zhao Jiaxu,Li Yujun,Zhang Lizheng,et al.UrgencyInvestigation Report of Geohazrad in 4.14 Yushu EarthquakeStroked Area,Qinghai Province.2010.
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