基于InSAR技术的门源Ms6.9地震形变特征分析

Analysis of Deformation Characteristics of Gate Source Ms6.9 Earthquake Based on InSAR Technology

青海省门源县位于青海东北部,地形复杂,高差悬殊,北边与冻龙岭断裂带相邻,向西又与托莱山断裂带相连,在2022年1月8日发生Ms6.9级地震。利用Sentinel-1A提供的雷达干涉像对,获取此次地震的同震地表形变场和地表沉降数据产品。干涉条纹结果表明,本次门源地震至少有3条割裂带,其中主震导致的割裂带最为明显,另外两条割裂带较为明显,长约3 km,推断是主震后1 h内发生的两次余震导致。主震割裂带沿NWW-SEE向破裂,此地理位置与冻龙岭西段与托莱山东段同时发生破裂的推论相符。地表形变数据结果显示,西南部抬升明显,最大值为0.66 m,东北部地表下沉严重,最大值0.54 m,其形变特征与左旋走滑型特征相吻合。地震震心波及半径为15~50 km,形变剖面反映出地表形变分布范围远大于垂直断层分布范围。

Menyuan County is located in the northeast of Qinghai province,where has complex terrain and great height difference,and which is adjacent to the Donglongling fault zone in the north and connected to the Tuolaishan fault zone in the west.The Ms6.9 earthquake occurred on January 8,2022 in this region.SAR images provided by Sentinel-1A are used to obtain the coseismic surface deformation field of this earthquake.The results show that there are at least three rift zones in the Menyuan earthquake,among which the main earthquake causes the most obvious rift zone,and the other two obvious rift zones with a length of about 3 km.It is inferred that two aftershocks occurred within 1 hour after the main earthquake.The main fracture zone broke along the NWW-SEE direction.The geographical location is consistent with the inference that the western segment of the Donglongling fault occurred simultaneously with the eastern segment of the Tolai Mountain fault.The results of surface deformation data show that the southwest is uplifted obviously with the maximum value of 0.66 m,while the northeast is subsidence seriously with the maximum value of 0.54 m.The deformation characteristics are consistent with the characteristics of left-lateral strike-slip type.The shockwave radius of epicenter is between 15 and 50 km and the deformation profile reflects that the distribution range of surface deformation is much larger than that of vertical fault.