SEISMOLOGY AND GEOLOGY ›› 2023, Vol. 45 ›› Issue (2): 401-421.DOI: 10.3969/j.issn.0253-4967.2023.02.006

Previous Articles     Next Articles

THE SURFACE RUPTURE CHARACTERISTICS BASED ON THE GF-7 IMAGES INTERPRETATION AND THE FIELD INVESTIGA-TION OF THE 2022 MENYUAN MS6.9 EARTHQUAKE

WANG Liao1)(), XIE Hong1,2),*(), YUAN Dao-yang3), LI Zhi-min4), XUE Shan-yu1), SU Rui-huan3), WEN Ya-meng3), SU Qi5)   

  1. 1)Lanzhou Institute of Seismology, China Earthquake Administration, Lanzhou 730000, China
    2)Lanzhou National Observatory of Geophysics, Lanzhou 730000, China
    3)School of Earth Sciences, Lanzhou University, Lanzhou 730000, China
    4)Qinghai Earthquake Agency, Xining 810001, China
    5)Faculty of Arts and Sciences, Beijing Normal University at Zhuhai, Zhuhai 519000, China
  • Revised:2022-09-26 Online:2023-04-20 Published:2023-05-18

结合野外考察的2022年门源MS6.9地震地表破裂带的高分七号影像特征

王辽1)(), 谢虹1,2),*(), 袁道阳3), 李智敏4), 薛善余1), 苏瑞欢3), 文亚猛3), 苏琦5)   

  1. 1)中国地震局兰州地震研究所, 兰州 730000l
    2)甘肃兰州地球物理国家野外科学观测研究站, 兰州 730000
    3)兰州大学, 地质科学与矿产资源学院, 兰州 730000
    4)青海省地震局, 西宁 810001
    5)北京师范大学珠海校区, 文理学院, 珠海 519000
  • 通讯作者: *谢虹, 女, 1982年生, 博士, 硕士生导师, 主要从事活动构造和构造地貌研究, E-mail: xiehlz@126.com
  • 作者简介:王辽, 男, 1998年生, 2021年于西南大学获地理信息科学专业学士学位, 现为中国地震局兰州地震研究所构造地质学专业在读硕士研究生, 主要从事活动构造与地震地质灾害研究, E-mail: 2667274493@qq.com
  • 基金资助:
    青海省重点研发与转化计划(2022-SF-138);国家自然科学基金(41302174);国家自然科学基金(42172227)

Abstract:

On January 8th, 2022, an MS6.9 earthquake occurred around Menyuan County(37.77°N, 101.26°E), Qinghai Province. The epicenter is located in the northeastern part of the Tibetan plateau, where the western section of the Lenglongling Fault meets the eastern section of the Tolaishan Fault. In order to know the spatial distribution of coseismic surface rupture zone as soon as possible, and determine the seismogenic structure, the post-earthquake GF-7 remote sensing images of the Menyuan MS6.9 earthquake were analyzed. Moreover, combining the interpretation of the GF-7 images and the field investigation, the distribution of the co-seismic surface rupture was determined and the typical coseismic landforms, and the image recognition features of various co-seismic landforms are interpreted and summarized. The results show that the earthquake produced two major surface rupture zones with a left-stepped oblique spatial arrangement. The main northern branch rupture distributes on the west side of the Lenglongling Fault, with a length of about 22km and a strike of 100°N~120°E, the secondary rupture of the southern branch distributes along the eastern section of the Tuolaishan Fault, with a length of about 4km and a strike of N90°E. The total length of the two rupture zones is about 26km.

Along the rupture zones, a series of typical left-lateral strike-slip coseismic landforms were formed, such as tensional fractures, tensional-shear fractures, pressure ridges, pressure bulges, left-lateral strike-slip gullies, as well as left-lateral strike-slip roadbeds, etc. We divided the surface rupture into six segments to conduct detailed observation and analysis, that is, the west of Daohe segment, Liuhuanggou segment, Honggou segment, Yongan River segment and Yikeshugou segment, from west to east among the main rupture zone of the north branch, as well as the secondary rupture zone of the south branch. In general, each co-seismic landform has its distinctive image characteristics, and we obtained them from the interpretation and summarization of the GF-7 images. The shear fractures located at the two ends of the main rupture and in the areas where the surface rupture is weak are zigzaggy on the remote sensing images, while the shear fractures located in the areas where the surface rupture is intense are shown as dark, wide and continuously smooth stripes; thrust scarps are represented on remote sensing images as shaded, narrow and slightly curved strips; the pressure ridges and pressure bulges exhibit black elliptical feature on the images that are parallel or at a smaller angle to the main rupture; tensional-shear fractures are displayed as black strips arranged in en echelon with a 30°~45° intersection angle with the main shear rupture, and their linear features are not as straight as those of shear ruptures yet are still distinct; the coseismic scarps formed on the ice are manifested in the images as traction bend and texture change. Based on the GF-7 images, the cumulative dislocations of typical sinistral landforms along the co-seismic surface rupture on Lenglongling Fault are interpreted and futher compared with the previous study. This is the first time of application of GF-7 to the strong earthquake geohazards monitoring since it was officially launched in August 2020. From this study, it can be seen that with its high resolution, GF-7 can be used to accurately identify faulted features. Not only it could provide information of the geometric roughness, complexity and segmentation of the fracture, but also can record clear dislocations of the landforms. The study of the GF-7 images in the 2022 Menyuan earthquake has showed that the GF-7 images can provide strong data support for the geology and geological hazard studies.

Key words: 2022 Menyuan earthquake, GF-7, co-seismic surface rupture characteristics, Lenglongling Fault, Tuolaishan Fault

摘要:

2022年1月8日, 青海省门源县发生了 MS6.9 地震。为及时全面了解地震同震地表破裂带的空间分布并准确判定发震构造, 文中通过对震后高分七号遥感影像进行解译判读, 综合野外考察核实, 获得了门源 MS6.9 地震同震地表破裂带的展布情况, 并识别出多种典型的同震破裂地貌, 总结了多种同震地貌的影像特征。结果表明, 此次地震产生了2条主要的地表破裂带, 呈左阶斜列展布。北支主破裂带分布于冷龙岭断裂西段, 长约22km, 走向 100°N~120°E; 南支次级破裂带分布在托莱山断裂东段的局部段上, 长约4km, 走向为N90°E, 2条破裂带总长约26km; 沿破裂带形成了一系列典型左旋走滑同震地貌, 如张裂隙、张剪裂隙、挤压脊、挤压鼓包、左旋纹沟、左旋断错路基等; 在此基础上, 文中还对冷龙岭地区典型左旋地貌的累积位错进行了测量, 并与前人的测量结果作对比研究, 得到了较为准确的测量结果。文中基于高分影像对断裂沿线典型的断错地貌开展研究, 不仅可为高分七号卫星数据的地质应用积累实例, 所得结果也可为未来构造地貌研究提供强有力的数据支撑。

关键词: 2022年门源地震, 高分七号, 地表破裂特征, 冷龙岭断裂, 托莱山断裂

CLC Number: