东昆仑断裂带东段塔藏断裂几何结构及滑动递减模型讨论

摘要/Abstract

摘要： 塔藏断裂位于东昆仑断裂带东段, 长约170 km, 与岷山断裂带共同构成巴颜喀拉块体的东北构造边界, 中部与岷江断裂、荷叶断裂、虎牙断裂的北延段交会, 构成岷山隆起的地貌边界。通过卫星影像解译结合构造地貌调查, 确定了断层属于全新世活动断层, 并利用断层走向弯曲和活动性、阶区等标志将塔藏断裂分为三段。西段为罗叉段, 总体走向NWW, 西侧与玛曲断裂形成左行左阶拉分区, 东侧在下黄寨村走向顺时针偏转至东北村段。中段为东北村段, 总体走向NW, 东侧在九寨沟口附近走向逆时针偏转至马家磨段。东段为马家磨段, 总体走向NWW, 西侧隔荷叶断裂、虎牙断裂的北延段与中段相接。东北村段以岷江断裂斜交点为界可分为南北两个次级段, 马家磨段以阶区为界划分为扎如次段、唐寨次段、勿角次段。罗叉段和马家磨段的地震离逝时间较近, 东北村段相对较远。断裂带整体呈反“S”形, 自西向东滑动速率总体呈减小趋势, 大部分水平变形转化为垂向的岷山隆升。结合不同段上的滑动速率, 发现东昆仑断裂东段滑动速率呈梯度下降特征与东昆仑断裂带东段断层弯曲的几何特征相对应。

关键词: 东昆仑断裂带, 塔藏断裂, 几何结构, 分段, 青藏高原

Abstract: The Tazang fault is located in the eastern part of the East Kunlun fault zone with a length of 170 km, which constitutes the northeast border of Bayan Har block with Minshan fault zone. Satellite image and geological survey have revealed evidence for Holocene movement along the fault. The fault can be divided into three sections by the segmental signs of strike-slip fault, such as geometric and tectonic discontinuities in combination of geomorphic features and fault zone materials. The Locha section generally strikes NWW, developed sinistral left-step with Maqu fault in the west, and rotates clockwise on the Xiahuangzhai village in the east. The Dongbei village section generally strikes NW, and rotates anticlockwise on the entrance of Jiuzhaijou in the east. We divided the Dongbei village section into two sub-sections, and the northern and southern sub-sections are separated by the Minjiang fault. The Majiamo section is divided into three sub-sections, namely Zharu, Tangzhai, Wujiao sections. The elapsed time in Loucha and Majiamo sections was relatively short. The linear horizontal slip of the east Kunlun fault zone transforms into the vertical movement of the Minjiang fault zone and Huya fault zone which trends nearly SN~NNE, and the uplift of Minshan. The fault sections splay out from NW to SE that has good correlation with the slip gradients along the east Kunlun fault.

Key words: East Kunlun fault zone, Tazang fault, Geometry, Segmentation, Tibetan Plateau

中图分类号:

P315.7

李建军, 蔡瑶瑶, 张军龙. 东昆仑断裂带东段塔藏断裂几何结构及滑动递减模型讨论[J]. 地震, 2019, 39(1): 20-28.

LI Jian-jun, CAI Yao-yao, ZHANG Jun-long. Geometric Structure and Slip Gradient Model of the Tazang Fault in the East Kunlun Fault Zone[J]. EARTHQUAKE, 2019, 39(1): 20-28.

参考文献

[1] 张国民, 田勤俭, 王辉. 可可西里—东昆仑活动构造带强震活动研究[J]. 地学前缘, 2003, 10(1): 39-46.
[2] 李建军, 张军龙, 蔡瑶瑶. 东昆仑断裂带历史地震、古地震及地震空区讨论[J]. 地震, 2017, 37(1): 103-111.
[3] 青海省地震局. 中国地震局地壳应力研究所.东昆仑活动断裂带[M]. 北京: 地震出版社, 1999.
[4] Van Der Woerd J, Tapponnier P, Ryerson F J, et al. Uniform postglacial slip-rate along the central 600 km of the Kunlun Fault (Tibet), from ²⁶Al, ¹⁰Be, and ¹⁴C dating of riser offsets, and climatic origin of the regional morphology[J]. Geophys J Int, 2002, 148(3): 356-388.
[5] Zhang J L, Ren J W, Chen C Y, et al. The Late Pleistocene activity of the eastern part of east Kunlun fault zone and its tectonic significance[J]. Sci China Earth Sci, 2014, 57: 439-453.
[6] 李陈侠, 袁道阳, 杨虎, 等. 东昆仑断裂带东段分支断裂—阿万仓断裂晚第四纪构造活动特征[J]. 地震地质, 2016.38(1): 44-64.
[7] Li J, Zhang Y Q, Li H L, et al. Revisiting Late Quaternary Sliprate along the Maqu Segment of the Eastern Kunlun Fault, Northeast Tibet[J]. Acta Geosicientia Sinica, 2016, 90(2): 486-502.
[8] Kirby E, Harkins N, Wang Er-Qi, et al. Slip rate gradients along the eastern Kunlun fault[J]. Tectonics, 2007, 26: TC2010.
[9] M7专项工作组. 中国大陆大地震中—长期危险性研究[M]. 北京: 地震出版社, 2012.
[10] 李陈侠. 东昆仑断裂带东段(玛沁—玛曲)晚第四纪长期滑动习性研究[D]. 北京: 中国地震局地质研究所, 2009.
[11] 李陈侠, 袁道阳, 杨虎, 等. 东昆仑断裂带东段分支断裂—阿万仓断裂晚第四纪构造活动特征[J]. 地震地质, 2016, 38(1): 44-64.
[12] 甘肃省地质局. 中华人民共和国区域地质矿产报告(1∶20万)—巴西幅[R]. 兰州, 1973.
[13] Li J J, Zhang J L, Cai Y Y. Geometric Detection of the Concealed Area of Tazang Fracture with Ground Penetrating Radar[J]. Revista de la Facultad de Ingeniería U.C.V., 2016, 31: 1-10.
[14] 张军龙, 任金卫, 付俊东, 等. 东昆仑断裂带东部塔藏断裂地震地表破裂特征及其构造意义[J]. 地震, 2012, 32(1): 1-16.
[15] 付国超, 张军龙, 蔡瑶瑶. 塔藏断裂马家磨段晚第四纪以来活动性研究[J]. 地震, 2017, 37(3): 51-60.
[16] 丁国瑜, 田勤俭, 孔凡臣, 等. 活断层分段: 原则、方法及应用[M]. 北京: 地震出版社, 1993.
[17] Zhang P Z, Peter Molnar, Xu X W. Late Quaternary and present-day rates of slip along the Altyn Tagh Fault, northern margin of the Tibetan Plateau[J]. Tectonics, 2007, 26(5): 1-25.
[18] 李建军, 张军龙, 郭玉涛. 晚更新世以来若尔盖盆地的地层划分及构造—气候意义[J]. 地震地质, 2016, 38(4): 950-963.
[19] 付俊东, 任金卫, 张军龙, 等. 东昆仑断裂东段塔藏断裂晚第四纪古地震研究[J]. 第四纪研究, 2012, 32: 473-483.
[20] Zhang J L. On fault evidence for a large earthquake in the late fifteenth century, Eastern Kunlunfault, China[J]. Journal of Seismology, 2017, 21(10): 1-9.
[21] 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.
[22] 何玉林. 青藏高原东缘主干断裂活动性及其构造变形模式研究[D]. 成都理工大学, 2013.
[23] 徐锡伟, 陈桂华, 王启欣, 等. 九寨沟地震发震断层属性及青藏高原东南缘现今应变状态讨论[J]. 地球物理学报, 2017, 60(10): 4018-4026.
[24] 谢祖军, 郑勇, 姚华建, 等. 2017年九寨沟M_S7.0地震震源性质及发震构造初步分析[J]. 中国科学(D辑), 2018, 48(1): 79-92.
[25] 季灵运, 刘传金, 徐晶, 等. 九寨沟M_S7.0地震的InSAR观测及发震构造分析[J]. 地球物理学报, 2017, 60(10): 4069-4082.
[26] 易桂喜, 龙锋, 梁明剑, 等. 2017年8月8日九寨沟M7.0地震及余震震源机制解与发震构造分析[J]. 地球物理学报, 2017, 60(10): 4083-4097.
[27] 任俊杰, 徐锡伟, 张世民, 等. 东昆仑断裂带东端的构造转换与2017年九寨沟M_S7.0地震孕震机制[J]. 地球物理学报, 2017, 60(10): 4027-4045.
[28] 张军龙, 陈长云, 李建军, 等. 青藏高原东缘活动块体隆升过程与形成机制[M]. 北京: 地质出版社, 2016.
[29] 周荣军, 李勇, Densmore A L, 等.青藏高原东缘活动构造[J]. 矿物岩石, 2006, 26(2): 40-51.
[30] 张军龙, 任金卫, 陈长云, 等. 岷江断裂全新世古地震参数及模型[J]. 地球科学-中国地质大学学报, 2013, 38(增1): 83-90.
[31] Guo X Y, Gao R, Xu X, et al. Longriba fault zone in eastern Tibet: An important tectonic boundary marking the westernmost edge of the Yangtze block[J]. Tectonics, 2015, 34: 970-985.