利用InSAR技术研究2016年青海门源MW5.9地震同震形变场及断层滑动分布

2016年1月21日, 青海省门源县冷龙岭断裂带附近发生了M_W5.9地震。 基于Sentinel-1A影像, 采用差分干涉雷达测量技术研究了此次地震产生的同震形变场, 结果表明, 门源地震的形变影响范围约20~30 km, 形变态势在升降轨道形变场均显示为隆升, 基本沿冷龙岭断裂呈近似同心圆展布, 推测可能是冷龙岭断裂与民乐—大马营断裂之间的一条逆断层, 沿雷达视线方向最大形变量级约为6 cm。 均匀滑动反演显示门源发震断层长7.3 km, 宽6.2 km, 走向298.6°, 倾角34.5°, 倾向宽度9.5 km, 沿走向滑动量为170 mm, 沿倾向滑动量为460 mm, 矩震级为M_W5.97; 分布式滑动反演显示门源地震以逆冲为主, 兼具少量右旋走滑分量, 滑动量主要集中在沿断层倾向方向, 距离地表5～15 km处, 最大滑动量约0.3 m, 位于断层倾向深度10 km处, 矩震级为M_W5.93。

Coseismic Deformation Field and Fault Slip Distribution of the 2016 Qinghai Menyuan MW5.9 Earthquake from InSAR measurement

On January 21^st, 2016, an M_W5.9 earthquake occurred nearby the fault zone of Lenglong ridge in Menyuan of Qinghai. In the paper, based on Sentinel-1A satellite image, we use differential interference radar measurement technology to study the seismic deformation. The results show that the Menyuan earthquake deformation influences scope of about 20~30 km, the deformation are displayed as uplift, the influenced area is concentric distribution along the Lenglong ridge fault zone,the causative fault is likely to be a reverse fault between Lenglong ridge fault and Minle-Damaying fault, and the maximum deformation magnitude along the radar line of sight direction is about 6.5 cm. Uniform slip inversion shows that the causative fault 7.3 km long, 6.2 km wide, 9.5 km depth, strike 298.6°, dip 34.5°, along the strike slip momentum is 170 mm, along the dip slip momentum is 460 mm,and the moment magnitude is M_W5.97. Distributed slip inversion shows that the earthquake is thrust tectonic quake with right-lateral strike-slip. Slide mainly is concentrated in the direction along the fault dip, where distance from the surface of the 5 km to 15 km, the biggest slide momentum is 0.3 m, in the fault depth of 10 km with moment magnitude of M_W5.93.