利用InSAR资料反演缅甸Mw6.8地震断层滑动分布

2011年3月24日缅甸东北部发生M_w6.8级地震.本文利用覆盖该地区的升降轨ALOS PALSAR数据,获取了该次地震的同震形变场,并采用灰度配准技术获取了其地表破裂位移.针对影像中因轨道不精确造成的非线性长波长误差,本文采用二次多项式曲面法予以去除,获取了更为精确的同震形变场.最后,基于弹性半空间形变模型反演了该地震的断层滑动分布.结果表明,该地震断层滑动以左旋走滑为主,兼具少许的倾滑运动分量,断层滑动主要集中分布在断层面0~10 km深度范围,最大滑动量达5 m,位于地表以下5 km深处.反演获得的地震标量矩为2.49×10¹⁹N·m,震级约为M_w6.8级.

The fault slip distribution of the Myanmar Mw6.8 earthquake inferred from InSAR measurements

On 24^th March 2011, an M_w6.8 earthquake occurred in Northeastern Myanmar, close to Thailand and Laos. We utilize both the ascending and descending orbit ALOS PALSAR data to obtain the coseismic deformation of this event. We also use a quadratic surface to remove the long wavelength orbital ramps related to imprecise orbit information. In addition to phase measurement, we also use offset-tracking technique to obtain coseismic deformation and fault trace, which can assist to construct the fault geometry. The fault slip distribution of Myanmar earthquake is inferred from the InSAR observation based on Okada half-space elastic model. The result shows that there is large sinistral strike-slip in the fault concentrating in the depth above 10 km, with a little dip-slip component. The maximum slip of 5 m is observed at a depth of 5 km. The inverted seismic moment is 2.49×10¹⁹N·m (M_w6.8).