地震地质 ›› 2020, Vol. 42 ›› Issue (2): 366-381.DOI: 10.3969/j.issn.0253-4967.2020.02.008

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基于高精度LiDAR数据的断裂活动习性精细定量——以香山-天景山断裂景泰小红山段为例

唐清1,2), 郑文俊1,2),*, 石霖1,2), 张冬丽1,2), 黄荣1,2)   

  1. 1)中山大学地球科学与工程学院, 广东省地球动力作用与地质灾害重点实验室, 广州 510275;
    2)南方海洋科学与工程广东省实验室(珠海), 珠海 519082
  • 收稿日期:2019-12-06 出版日期:2020-04-20 发布日期:2020-07-13
  • 通讯作者: * 郑文俊, 男, 教授, 博士生导师, 主要从事新构造、 活动构造、 构造地貌与地震危险性方面的研究, E-mail: zhengwenjun@mail.sysu.edu.cn。
  • 作者简介:唐清, 男, 1997年生, 2019年于中山大学地球科学与工程学院获地质学专业学士学位, 现为中山大学地球科学与工程学院构造地质学专业在读硕士研究生, 主要从事活动构造与构造地貌方面的研究, 电话: 020-84112417, E-mail: tangq28@mail2.sysu.edu.cn。
  • 基金资助:
    国家重点研发计划项目(2017YFC1500101)、 第二次青藏高原综合科学考察(2019QZKK0901)和国家自然科学基金(41590861, 41774049, 41674051, 41602224)共同资助

QUANTITATIVE STUDY OF FAULT ACTIVITY BASED ON HIGH-PRECISION AIRBORNE LiDAR DATA: A CASE OF XIAOHONGSHAN FAULT IN XIANGSHAN-TIANJINGSHAN FAULT ZONE

TANG Qing1,2), ZHENG Wen-jun1,2), SHI Lin1,2), ZHANG Dong-li1,2), HUANG Rong1,2)   

  1. 1)Guangdong Provincial Key Laboratory of Geodynamics and Geohazards, School of Earth Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, China;
    2)Guangdong Laboratory of Southern Ocean Science and Engineering(Zhuhai), Zhuhai 519082, China
  • Received:2019-12-06 Online:2020-04-20 Published:2020-07-13

摘要: 高精度、 高分辨率的地形地貌数据是活动构造定量研究的重要基础数据。 传统研究方法中, 通过航卫片或遥感影像解译只能获取二维平面特征, 中等分辨率DEM(5~10m网格单元)只适用于大尺度三维地貌特征的提取。 激光雷达测量(Light Detection and Ranging, LiDAR)技术可直接对地貌进行高精度、 全方位的三维地表形态测量, 为活动构造研究提供了精细的地貌形态数据, 有助于深化对断裂带地表破裂过程和断裂活动特性的理解。 文中选取青藏高原东北缘香山-天景山断裂带西段的景泰小红山断裂中一段断错地貌明显的断裂段作为研究对象, 基于高精度LiDAR数据生成了景泰小红山断裂0.3m高分辨率的数字高程模型(DEM), 沿断裂带详细识别并测量了地貌标志(冲沟、 山脊和阶地)的断错位移, 获得了地貌标志的82个水平位移和62个垂直位移, 并分析了不同方向上的位移丛集特征。 结果显示, 沿断裂的水平与垂直位移均可识别出5个丛集, 其中最小丛集可能指示最新一次地震的同震位移, 而其它位移丛集则反映了断裂带多次地震活动累积的结果。 通过对多个断错标志的水平和垂直位移合成的滑动矢量进行分析, 可以看出该断层段的运动习性具有分段不均匀特征, 不同段落的倾滑矢量有一定的差异。

关键词: 高精度LiDAR, 断错地貌, 位移丛集, 滑动矢量, 走滑断裂

Abstract: High-precision and high-resolution topography are the basis of quantitative study of active tectonics. Traditional methods are mainly interpreted from the remote sensing image and can only obtain two-dimensional, medium-resolution DEM(5~10m grid unit)or local three-dimensional surface deformation characteristics. A combination of offset and micro-relief information is essential for understanding the long-term rupture pattern of faults, such as in seismic hazard evaluation. The recently developed high-resolution light detection and ranging(LiDAR)technology can directly carry out high-precision and omni-directional three-dimensional measurement of the landform, and provide fine geomorphologic data for the study of active tectonics, which is helpful to deepen the understanding of surface rupture process and fault activity characteristics. In this study, we take part of the Xiaohongshan Fault, the western segment of Xiangshan-Tianjingshan Fault located in Gansu Province(NE Tibet), as an example of how LiDAR data may be used to improve the study of active faults. Using the airborne LiDAR technology, we obtain the three-dimensional surface deformation characteristics with high accuracy and establish the three-dimensional topographic model of the fault geomorphic. A high-resolution digital elevation model(DEM)of the Jingtai-Xiaohongshan Fault was extracted based on high-precision LiDAR data. Then the faulted geomorphic markers(gullies, ridges and terraces)were measured in detail along the fault, and different offset clusters and long-term sliding vector of different segments of the fault were finally acquired. We obtained the 82 horizontal displacements and 62 vertical displacements of geomorphic markers. According to the offset amounts, we observed peaks in the histogram by using the method of cumulative offset probability density and interpreted that each peak may represent an earthquake that ruptured the Xiaohongshan Fault. The results show that the horizontal and vertical displacements fall into five clusters, and the smallest cluster may indicate the coseismic slip of the most recent earthquake, while the other clusters may represent the slip accumulation of multiple preceding earthquakes. The sliding vectors constrained by the horizontal and vertical displacement of several typical geomorphic markers show obvious differences on different segments of the fault. The results show that the fault segment is divided into three segments from west to east, which indicates that the fault activity is not uniform along the fault.

Key words: high-precision LiDAR data, faulted geomorphology, offset cluster, sliding vector, strike-slip faults

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