2021年云南漾濞M_(S)6.4地震同震位移场和震源滑动模型反演

Slip Model and Co-seismic Displacement Field of the 2021 Yangbi, Yunnan M_(S)6.4 Earthquake

基于2021年云南漾濞M_(S)6.4地震震中周围40 km范围内仅有的2个强震台近场强震记录进行基线校正并给出同震位移。同时分析强震和GPS资料呈现的永久位移场特征,利用快速获取的GPS同震位移场和InSAR升、降轨资料分别独立和联合反演该地震的震源滑动模型,并进一步展现全空间预测位移场分布。结果表明:(1)漾濞地震水平同震位移场呈现以右旋走滑为主的错动。(2)GPS和InSAR独立和联合反演所得的震源静态滑动范围基本一致,均呈现单侧破裂的总体特征,即主要滑动均发生在震中东南部。6种模型的最大滑动量分别为0.74 m、0.66 m、0.44 m、0.45 m、0.47 m和0.47 m,反演的矩震级为MW5.9~6.3。(3)根据震源滑动模型正演所得的漾濞地震全空间预测水平同震位移场与实际观测位移场一致性较好,震中南、北两侧向内挤压,东、西两侧向外拉张,符合走滑型地震所产生的四象限位移场分布特征。

On the basis of the near-field strong motion records within 40 km around the epicenter of the Yangbi M_(S)6.4 earthquake in Yunnan on May 21,2021,we used an improved automatic empirical baseline correction method to estimate the co-seismic displacement.We analyzed the characteristics of strong motion and GPS co-seismic displacement field.We inverted independently and jointly the source slip model using GPS data and InSAR ascending-and descending-orbit data,and further proposed the distribution of the predicted,full-space,co-seismic displacement field based on the slip model.The results showed that:(1)The horizontal co-seismic displacement field showed that the fault dislocation was dominated by right-lateral strike-slip.(2)The static slip range of the source obtained by independent-and joint-inversion of GPS and InSAR was basically the same.The maximum slip occurred in the south of the epicenter.The maximum slips of the source by the 6 models were respectively 0.74 m,0.66 m,0.44 m,0.45 m,0.47 m and 0.47 m.The inverted MW ranged from 5.9 to 6.3.(3)The predicted,full-space,horizontal,co-seismic displacement field of the Yangbi earthquake by the slip model was in good agreement with the observed,horizontal,co-seismic displacement field.The north and south parts of the epicenter were compressing inward,while the east and west parts were stretching outward.This was consistent with the characteristics of the co-seismic displacement field produced by a strike-slip earthquake.