塔藏断裂马家磨段晚第四纪以来活动性研究
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摘要
近NW向展布的塔藏断裂带位于巴颜喀拉块体东北缘,研究其东部活动性质对于探讨青藏高原东缘形成的动力学机制具有重要意义,也是判断断裂带地震危险性的基础。基于对塔藏断裂东部马家磨段卫星影像解译、地质地貌特征及地表破裂调查,对于其活动性得到以下认识:断裂空间几何展布总体呈NWW走向,倾向NE,起于漳扎镇西,止于沙尕里东南部,全长近60km。自西向东可以分为扎如沟段、唐寨段、勿角段3个次级段落,均为左旋右阶排列,阶区规模较小,最大阶区长约2km。广泛分布的构造地貌和古地震造成的破裂标志表明该段全新世仍有活动,断裂的最新活动时间为480±40aB.P.。该活动断裂为巴颜喀拉块体向东滑移提供了边界条件。
The strike of Tazang fault zone which is located in the northeast edge of Bayan Hara block extends in the direction of NW.The research of the east extension and the east end point of the NW trending tectonics are of great impetus to explore the dynamic mechanism of the formation of the eastern margin of the Qinghai-Tibet plateau.It is the foundation of authenticating the danger of earthquake.Based on the interpretation of satellite image,geological and geomorphological features and surface rupture of the Majiamo section of the Tazang fault,the tectonic activity of the fault is recognized as follows:The Majiamo section of the Tazang fault extends northward to the southeastern part of the Shagali area.The total length is nearly 60 km.The sub-division of Majiasha is Zharu,Tangzhai and Wujiao respectively.And they are all left-lateral.The largest order is about 2km.The widely distributed tectonic landforms and the rupture signs caused by paleo-earthquake indicate that this section has experienced many tectonic activities,and the latest activity of fault occurred in 480±40aBP.The active features of the Majiamo segment indicate that the Tazang fault is one of the major faults in the east extension of the East Kunlun fault zone,which is providing an evidence for the Bayan Hara block extending along the East Kunlun fault zone to the SEE "escape".
The strike of Tazang fault zone which is located in the northeast edge of Bayan Hara block extends in the direction of NW.The research of the east extension and the east end point of the NW trending tectonics are of great impetus to explore the dynamic mechanism of the formation of the eastern margin of the Qinghai-Tibet plateau.It is the foundation of authenticating the danger of earthquake.Based on the interpretation of satellite image,geological and geomorphological features and surface rupture of the Majiamo section of the Tazang fault,the tectonic activity of the fault is recognized as follows:The Majiamo section of the Tazang fault extends northward to the southeastern part of the Shagali area.The total length is nearly 60 km.The sub-division of Majiasha is Zharu,Tangzhai and Wujiao respectively.And they are all left-lateral.The largest order is about 2km.The widely distributed tectonic landforms and the rupture signs caused by paleo-earthquake indicate that this section has experienced many tectonic activities,and the latest activity of fault occurred in 480±40aBP.The active features of the Majiamo segment indicate that the Tazang fault is one of the major faults in the east extension of the East Kunlun fault zone,which is providing an evidence for the Bayan Hara block extending along the East Kunlun fault zone to the SEE "escape".
引文
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[4]Van Der Woerd J,Tapponnier P,Ryerson F J,et al.Uniform post glacial slip-rate along the central600km of the Kunlun Fault(Tibet),from26 Al,10Be,and 14 C dating of riser offsets,and climatic origin of the regional morphology[J].Geophysical Journal International,2002,148(3):356-388.
[5]Wen X Z,Yi G X,Xu X W.Background and precursory seismicities along and surrounding the Kunlun fault before the MS8.1,Kokoxili earthquake,China[J].Journal of Asian Earth Sciences,2007,30:63-72.
[6]闻学泽,徐锡伟,龙锋,等.中国大陆东部中-弱活动断层潜在地震最大震级评估的震级-频度关系模型[J].地震地质,2007,29(2):236-253.
[7]张军龙,任金卫,陈长云,等.东昆仑断裂带东部晚更新世以来活动特征及其大地构造意义[J].中国科学:地球科学,2014,44(4):654-667.
[8]任俊杰.龙日坝断裂带晚第四纪活动及与其周边断裂的运动学关系[D].北京:中国地震局地质研究所,2013.
[9]袁道阳,杨青云,雷中生,等.四川北部地区三次中强历史地震补充考证[J].地震工程学报,2016,38(2):226-235.
[10]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,2005,25(1):34-44.
[11]邵志刚,周龙泉,蒋长胜,等.2008年汶川MS8.0地震对周边断层地震活动的影响[J].地球物理学报,2010,53(8):1 784-1 795.
[12]付俊东,任金卫,张军龙,等.东昆仑断裂带东段塔藏断裂晚第四纪古地震研究[J].第四纪研究,2012,32(3):473-483.
(1)样品由美国BETA实验室测试
[2]Eric Kirby,Nathan Harkins,Wang Erqi,et al.Slip-rate gradients along the eastern kunlun fault[J].Tectonics,2006,26:1-16.
[3]徐锡伟,于贵华,马文涛,等.昆仑山地震(MW7.8)破裂行为、变形局部化特征及其构造内涵讨论[J].中国科学(D辑:地球科学),2008,38(7):785-796.
[4]Van Der Woerd J,Tapponnier P,Ryerson F J,et al.Uniform post glacial slip-rate along the central600km of the Kunlun Fault(Tibet),from26 Al,10Be,and 14 C dating of riser offsets,and climatic origin of the regional morphology[J].Geophysical Journal International,2002,148(3):356-388.
[5]Wen X Z,Yi G X,Xu X W.Background and precursory seismicities along and surrounding the Kunlun fault before the MS8.1,Kokoxili earthquake,China[J].Journal of Asian Earth Sciences,2007,30:63-72.
[6]闻学泽,徐锡伟,龙锋,等.中国大陆东部中-弱活动断层潜在地震最大震级评估的震级-频度关系模型[J].地震地质,2007,29(2):236-253.
[7]张军龙,任金卫,陈长云,等.东昆仑断裂带东部晚更新世以来活动特征及其大地构造意义[J].中国科学:地球科学,2014,44(4):654-667.
[8]任俊杰.龙日坝断裂带晚第四纪活动及与其周边断裂的运动学关系[D].北京:中国地震局地质研究所,2013.
[9]袁道阳,杨青云,雷中生,等.四川北部地区三次中强历史地震补充考证[J].地震工程学报,2016,38(2):226-235.
[10]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,2005,25(1):34-44.
[11]邵志刚,周龙泉,蒋长胜,等.2008年汶川MS8.0地震对周边断层地震活动的影响[J].地球物理学报,2010,53(8):1 784-1 795.
[12]付俊东,任金卫,张军龙,等.东昆仑断裂带东段塔藏断裂晚第四纪古地震研究[J].第四纪研究,2012,32(3):473-483.
(1)样品由美国BETA实验室测试