基于InSAR分析2015年尼泊尔MW7.8地震形变场特征及断层滑动分布反演

doi:10.12196/j.issn.1000-3274.2020.04.006

摘要/Abstract

摘要： 2015年4月25日尼泊尔发生了M_W7.8地震, 本文基于震前、震后两景Sentinel-1A雷达影像, 采用D-InSAR两轨差分干涉法提取了此次地震的同震形变场。结果显示, 同震形变场位于喜马拉雅造山带—主边界逆冲断裂(MBT)和主前锋逆冲断裂(MFT)附近, 形变场整体表现为自西北向往东南方向延伸近150 km的纺锤形包络状, 以大面积隆起抬升形变为主, 视线向最大隆升形变达1.18 m, 抬升区北侧存在一小沉陷区, 以InSAR观测值定位同震最大形变中心。基于均匀介质弹性半空间模型(Okada模型)与InSAR观测数据反演了断层滑动分布。反演结果表明该地震属于典型逆冲型地震, 发震断层为主喜马拉雅逆冲断裂(MHT), 同震破裂从主喜马拉雅逆冲断裂(MHT)向上沿着主前锋逆冲断裂(MFT)传递。基于InSAR同震形变场局部形变细节, 结合震区地质背景、断裂分布及断层运动特征, 获得了同震破裂拟出露地表迹线。

关键词: 2015年尼泊尔M_W7.8地震, D-InSAR, 同震形变场, 滑动分布反演

Abstract: The Nepal M_W7.8 earthquake occurred on April 25, 2015. Based on Sentinel-1A SAR images before and after the earthquake, the coseismic deformation field was derived by D-InSAR method. InSAR observation results show that the coseismic deformation field was located near the Main Boundary Thrust Fault (MBT) and the Main Frontal Thrust Fault (MFT) in the Himalayan Orogenic Belt. The whole deformation field showed a spindle-shaped envelope extending about 150 km in length from northwest to southeast. The coseismic deformation is dominated by uplift in large area. The maximum uplift in line-of-sight (LOS) is 1.18m. There was a small subsidence area to the north of the uplift area. The maximum coseismic deformation center is obtained from InSAR deformation. Based on the Okada model and InSAR observations, we inverted the fault slip distribution. Inversion results show that the earthquake is a typical thrusting event. The main seismogenic fault is Main Himalayan Thrust Fault (MHT). And coseismic rupture is transmitted upward from Main Himalayan Thrust Fault (MHT) along Main Frontal Thrust Fault (MFT). In this paper, based on the details of InSAR coseismic deformation field, combined with the geological background, fault distribution and fault movement characteristics of the earthquake area, the preliminary interpretation and description of the pseudo coseismic fracture surface trace is completed.

Key words: 2015 Nepal M_W7.8 earthquake, D-InSAR, Coseismic deformation field, Fault slip inversion

中图分类号:

P315.7

徐小波, 马超, 洪顺英, 连达军, 张迎峰. 基于InSAR分析2015年尼泊尔M_W7.8地震形变场特征及断层滑动分布反演[J]. 地震, 2020, 40(4): 76-89.

XU Xiao-bo, MA Chao, HONG Shun-ying, LIAN Da-jun, ZHANG Ying-feng. Analysis of Coseismic Displacements due to the M_W7.8 Nepal Earthquake Using InSAR Data and Inversion of Fault Slip Distribution[J]. EARTHQUAKE, 2020, 40(4): 76-89.

参考文献

[1] Parameswaran R M, Natarajan T, Rajendran K, et al. Seismotectonics of the April-May 2015 Nepal earthquake: An assessment based on the aftershock patterns, surface effects and deformational characteristics[J]. Journal of Asian Earth Sciences, 2015, 111: 161-174.
[2] 雷东宁, 蔡永建, 李恒, 等. 尼泊尔M_S8.1地震构造背景及对周边地区地震活动趋势的影响[J]. 大地测量与地球动力学, 2015, 35(5): 738-741.
LEI Dong-ning, CAI Yong-jian, LI Heng, et al. The seismotectonic setting and effect on the Neighbouring seismicity trend of M_S8.1 earthquake on April 25, 2015[J]. Journal of Geodesy and Geodynamics, 2015, 35(5): 738-741 (in Chinese).
[3] 吴中海, 赵根模, 刘杰. 2015年尼泊尔M_S8.1地震构造成因及对青藏高原及邻区未来强震趋势的影响[J]. 地质学报, 2016, 90(6): 1062-1085.
WU Zhong-hai, ZHAO Gen-mo, LIU Jie, et al. Tectonic genesis of the 2015 M_S8.1 Nepal great earthquake and its influence on future strong earthquake tendency of Tibetan Plateau and its adjacent region[J]. Acta Geologica Sinica, 2016, 90(6): 1062-1085 (in Chinese).
[4] Paul J, Bürgmann R, Gaur V K, et al. The motion and active deformation of India[J]. Geophysical Research Letters, 2001, 28(4): 647-650.
[5] 刘静, 纪晨, 张金玉, 等. 2015年4月25日尼泊尔M_W7.8级地震的孕震构造背景和特征[J]. 科学通报, 2015, 60(27): 2640-2655.
LIU Jing, JI Chen, ZHANG Jin-yu, et al. Tectonic setting and general features of coseismic rupture of the 25 April, 2015 M_W7.8 Gorkha, Nepal earthquake[J]. Chinese Science Bulletin, 2015, 60(27): 2640-2655 (in Chinese).
[6] Grandin R, Doin M P, Bollinger L, et al. Long-term growth of the Himalaya inferred from interseismic InSAR measurement[J]. Geology, 2012, 40(12): 1059-1062.
[7] 张勇, 许力生, 陈运泰. 2015年尼泊尔M_W7.9地震破裂过程: 快速反演与初步联合反演[J]. 地球物理学报, 2015, 58(5): 1804-1811.
ZHANG Yong, XU Li-sheng, CHEN Yun-tai, et al. Rupture process of the 2015 Nepal M_W7.9 earthquake: Fast inversion and preliminary joint inversion[J]. Chinese Journal of Geophysics, 2015, 58(5): 1804-1811 (in Chinese).
[8] 刘刚, 王琪, 乔学军, 等. 用连续GPS与远震体波联合反演2015年尼泊尔中部M_S8.1地震破裂过程[J]. 地球物理学报, 2015, 58(11): 4287-4297.
LIU Gang, WANG Qi, QIAO Xue-jun, et al. The 25 April 2015 Nepal M_S8.1 earthquake slip distribution from joint inversion of teleseismic, static and high-rate GPS data[J]. Chinese Journal of Geophysics, 2015, 58(11): 4287-4297 (in Chinese).
[9] 方进, 许才军, 温扬茂, 等. 基于方差分量估计的2015年尼泊尔M_W7.8地震同震滑动分布[J]. 地球物理学报, 2019, 62(3): 923-939.
FANG Jin, XU Cai-jun, WEN Yang-mao, et al. Coseismic slip distribution of 2015 Gorkha (Nepal) M_W7.8 earthquake determined using the Helmert variance component estimation[J]. Chinese Journal of Geophysics, 2019, 62(3): 923-939 (in Chinese).
[10] Avouac J P, Meng L S, Wei S J, et al. Lower edge of locked Main Himalayan Thrust unzipped by the 2015 Gorkha earthquake[J]. Nature Geoscience, 2015, 8(9): 708-711.
[11] 张贝, 程惠红, 石耀霖. 2015年4月25日尼泊尔M_S8.1大地震的同震效应[J]. 地球物理学报, 2015, 58(5): 1794-1803.
ZHANG Bei, CHENG Hui-hong, SHI Yao-lin, et al. Calculation of the co-seismic effect of M_S8.1 earthquake, Apirl 25, 2015, Nepal[J]. Chinese Journal of Geophysics, 2015, 58(5): 1794-1803 (in Chinese).
[12] 屈春燕, 左荣虎, 单新建, 等. 尼泊尔M_W7.8地震InSAR同震形变场及断层滑动分布[J]. 地球物理学报, 2017, 60(1): 151-162.
QU Chun-yan, ZUO Rong-hu, SHAN Xin-jian, et al. Coseismic deformation field of the Nepal M_S8.1 earthquake from Sentinel-1A/InSAR data and fault slip inversion[J]. Chinese Journal of Geophysics, 2017, 60(1): 151-162 (in Chinese).
[13] 杨晓平, 吴果, 陈立春, 等. 青藏高原南缘2015年尼泊尔M_W7.8地震发震构造[J]. 地球物理学报, 2016, 59(7): 2528-2538.
YANG Xiao-ping, WU Guo, CHEN Li-chun, et al. The seismogenic structure of the April 25, 2015 M_W7.8 Nepal earthquake in the southern margin of Qinghai-Tibetan Plateau[J]. Chinese Journal of Geophysics, 2016, 59(7): 2528-2538 (in Chinese).
[14] Massonnet D, Rossi M, Carmona C, et al. The displacement field of the Landers earthquake mapped by radar interferometry[J]. Nature, 1993, 364(6433): 138-142.
[15] Feng G C, Hetland E A, Ding X L, et al. Coseismic fault slip of the 2008 M_W7.9 Wenchuan earthquake estimated from InSAR and GPS measurements[J]. Geophysical Research Letters, 2010, 37(1): L01302.
[16] 邵叶, 申旭辉, 洪顺英, 等. 基于D-InSAR技术的玉树M_S7.1地震同震形变场提取与分析[J]. 地震, 2011, 31(3): 37-45.
SHAO Ye, SHEN Xu-hui, HONG Shun-ying, et al. Calculation and analysis of the coseismic deformation of the 2010 Yushu M_S7.1 earthquake based on D-InSAR technology[J]. Earthquake, 2011, 31(3): 37-45 (in Chinese).
[17] 孟国杰, Linlin Ge, 伍吉仓, 等. 雷达干涉测量在地震形变研究中的应用[J]. 地震, 2012, 32(2): 105-113.
MENG Guo-jie, Linlin Ge, WU Ji-cang, et al. Application of DInSAR in earthquake deformation studies[J]. Earthquake, 2012, 32(2): 105-113 (in Chinese).
[18] 黄其欢, 夏磊凯, 刘学敏, 等. 利用Sentinel-1A SAR影像监测尼泊尔“4·25”地震变形[J]. 河海大学学报(自然科学版), 2016, 44(5): 427-431.
HUANG Qi-huan, XIA Lei-kai, LIU Xue-min, et al. Seismic deformation monitoring of Nepal April 25 earthquake using Sentinel-1A SAR data[J]. Journal of Hohai University (Natural Sciences), 2016, 44(5): 427-431 (in Chinese).
[19] 杨珍, 张永志, 吴然, 等. 基于D-InSAR技术的当雄地震形变场提取研究[J]. 测绘工程, 2016, 25(8): 5-10.
YANG Zhen, ZHANG Yong-zhi, WU Ran, et al. On the extraction of surface deformation caused by Damxung earthquake based on D-InSAR technology[J]. Engineering of Surveying and Mapping, 2016, 25(8): 5-10 (in Chinese).
[20] 刘杰, 赵根模, 吴中海. 2015年尼泊尔8.1级大地震前后喜马拉雅带地震活动图像演变[J]. 地质力学学报, 2017, 23(1): 173-181.
LIU Jie, ZHAO Gen-mo, WU Zhong-hai. The evolution of seismic activity image in the Himalaya belt before and after 2015 Nepal M8.1 great earthquake[J]. Journal of Geomechanics, 2017, 23(1): 173-181 (in Chinese).
[21] 单新建, 马瑾, 柳稼航, 等. 星载D-InSAR技术及初步应用以西藏玛尼地震为例[J]. 地震地质, 2001, 23(3): 439-446.
SHAN Xin-jian, MA Jin, LIU Jia-hang, et al. The theory of D-InSAR and its application to mapping the displacement fields of earthquake[J]. Seismology and geology, 2001, 23(3): 439-446 (in Chinese).
[22] 赵强. 利用InSAR技术研究2016年青海门源M_W5.9地震同震形变场及断层滑动分布[J]. 国际地震动态, 2017, (8): 123-124.
ZHAO Qiang. Coseismic deformation field and fault slip distribution of the 2016 Qinghai Menyuan M_W5.9 Earthquake from InSAR measurement[J]. Recent Developments in World Seismology, 2017, (8): 123-124 (in Chinese).
[23] 纪润池, 申旭辉, 张景发, 等. 中小地震三维形变场重构方法研究与同震滑动分布反演以2016年5月22日定日M_W5.3地震为例[J]. 地震, 2019, 39(4): 84-97.
JI Run-chi, SHEN Xu-hui, ZHANG Jing-fa, et al. Research on reconstruction method of three-dimensional deformation field for small and medium earthquakes and inversion of co-seismic slip distribution: A case study of May 22 2016 M_W5.3 Dingri earthquake[J]. Earthquake, 2019, 39(4): 84-97 (in Chinese).
[24] Ma C, Cheng X Q, Yang Y L, et al. Investigation on mining subsidence based on multitemporal InSAR and time-series analysis of the small baseline subset: Case study of working faces 22201-1/2 in Bu’ertai Mine, Shendong Coalfield, China[J]. Remote Sensing, 2016, 8(11): 951-976.
[25] 廖明生, 王腾. 时间序列InSAR技术与应用[M]. 北京: 科学出版社, 2014.
LIAO Ming-sheng, WANG Teng. Time series InSAR technology and application[M]. Beijing: Science Press, 2014 (in Chinese).
[26] Dong S C, Huang L L. Mapping surface displacement based on D-InSAR technique[R]. 2011 International Conference on Remote Sensing, Environment and Transportation Engineering, 2011.
[27] 何曙光, 张学东, 庞蕾, 等. 雷达干涉测量中基线估计常用方法分析[J]. 测绘通报, 2016, (9): 20-23, 28.
HE Shu-guang, ZHANG Xue-dong, PANG Lei, et al. Analysis of common methods of baseline estimation in radar interferometry[J]. Bulletin of Surveying and Mapping, 2016, (9): 20-23, 28 (in Chinese).
[28] 温扬茂, 许才军, 刘洋, 等. 升降轨InSAR数据约束下的2007年阿里地震反演分析[J]. 测绘学报, 2015, 44(6): 649-654.
WEN Yang-mao, XU Cai-jun, LIU Yang, et al. The 2007 Ali earthquake inversion from ascending and descending InSAR observations[J]. Acta Geodaetica et Cartographica Sinica, 2015, 44(6): 649-654 (in Chinese).
[29] 徐小波, 屈春燕, 单新建, 等. CR-InSAR与PS-InSAR联合解算方法及在西秦岭断裂中段缓慢变形研究中的应用[J]. 地球物理学报, 2016, 59(8): 2796-2805.
XU Xiao-bo, QU Chun-yan, SHAN Xin-jian, et al. Mapping slow deformation of the middle segment of the West Qinling fault using the combined algorithm of CR-InSAR and PS-InSAR[J]. Chinese Journal of Geophysics, 2016, 59(8): 2796-2805 (in Chinese).
[30] Okada Y. Internal deformation due to shear and tensile fault in a half-space[J]. Bulletin of the Seismological Society of America, 1992, 82(2): 1018-1040.