2021年3月19日西藏自治区那曲市比如县发生MS 6.1地震,因西藏地区地球物理台站少且分布稀疏,无法较好地获取地震发生前后地球物理场变化信息。基于Sentinel-1卫星升、降轨SAR数据及数字高程模型SRTM3,利用合成孔径雷达差分干涉测量技术(DInSAR)技术,获取震区地震同震形变场信息,判断地表形变场的变化。结果表明:本次地震由正断兼走滑的断层运动造成,升、降轨沿雷达视线向的最大沉降量分别为2.4 cm(升轨)和2.8 cm(降轨),最大抬升量分别为0.6 cm(升轨)和3.5 cm(降轨)。
On March 19, 2021, an earthquake with MS 6.1 occurred in Nagqu City, Tibet Autonomous Region. Due to the few geophysical stations in Tibet and their sparse distribution, it is impossible to obtain the change information in the geophysical field before and after the earthquake. Based on Sentinel-1 satellite ascending and descending SAR data and digital elevation model SRTM3, the coseismic deformation field information of earthquake area is obtained by using differential synthetic aperture radar interferometry (DInSAR) technology, and the change of surface deformation field is judged. The results show that the earthquake was caused by normal fault and strike-slip fault movement. The maximum subsidence of the ascending and descending tracks along the radar line of sight are 2.4 cm (ascending track) and 2.8 cm (descending track) respectively, and the maximum uplift are 0.6 cm (ascending track) and 3.5 cm (descending track) respectively.
2023,44(2): 134-140 收稿日期:2022-12-15
DOI:10.3969/j.issn.1003-3246.2023.02.017
基金项目:中国地震局地震监测、预报、科研三结合课题(项目编号:3JH-202201032)
作者简介:桑杰卓玛(1998—),女,毕业于长安大学地质工程与测绘学院测绘工程专业,助理工程师,从事地震监测预报相关工作。E-mail:2118762942@qq.com
参考文献:
宫熙雯,张正加,陈启浩,等.融合DInSAR和MAI技术反演九寨沟地震三维形变场[J].测绘工程,2021,30(5):49-57.
田雷,张小涛,解孟雨,等. 2021年3月19日西藏比如MS 6.1地震总结[J]. 地震地磁观测与研究,2021,42(2):42-57.
李玉丽,李启雷. 2021年西藏比如MS 6.1地震序列发震构造分析[J].地震研究,2022,45(1):54-65.
刘学武,胡波,莫玉娟,等. DInSAR技术监测玉树地震同震形变场的研究[J].测绘工程,2011,20(6):38-39.
吴中海,赵希涛,吴珍汉,等.西藏安多-错那湖地堑的第四纪地质、断裂活动及其运动学特征分析[J].第四纪研究,2005,25(4):490-502.
杨红磊,彭军还.基于DInSAR和MAI技术揭示地震三维形变场[J].地球物理学进展,2014,29(6):2580-2586.
袁伏全,黄浩,孙世瑞,等. 2021年西藏比如MS 6.1地震震源机制解与发震构造分析[J].地震地磁观测与研究,2021,42(Z1):186-188.
张明,高涵,牛玉芬,等. 2016年门源地震震源机制DInSAR同震形变反演[J].地球物理学进展,2017,32(3):1 089-1 094.
张威,吴仍武,刘勇. D-InSAR技术在地面变形监测中的应用[J].科技信息,2014,(1):79.
张艳梅,江在森,李斐,等.基于DInSAR的2001年昆仑山口西8.1级大地震形变探测[J].大地测量与地球动力学,2007,27(3):12-17.
Massonnet D, Rossi M, Carmona C, et al. The displacement field of the Landers earthquake mapped by radar interferometry[J]. Nature, 1993, 364 (6 433): 138-142.