2020年3月西藏改则M_(S)≥5.0地震震前电离层异常特征

Characteristics of Ionospheric Anomalies Before the Gaize M_(S)≥5.0 Earthquakes in March 2020 in Tibet

基于2020年3月10日、12日西藏改则M_(S)5.0、M_(S)5.1地震前后GNSS基准站及电离层垂测站观测数据,对比分析了地震前后电离层VTEC异常分布、站点VTEC及站点fo F2时间序列变化。结果显示:3月9日、3月11日震中附近区域电离层多参量同步异常变化显著,异常时空演化特征与地震-电离层耦合特征一致,满足地震-电离层异常扰动判识标准。本文认为该异常扰动可能与西藏改则M_(S)5.0、M_(S)5.1地震孕育过程有关,进一步佐证了地震-电离层效应的短临性和局地性特征。

A magnitude 7.4 earthquake was occurred in Maduo,Qinghai on May 22,2021.In Sichuan,the far-field co-seismic displacements caused by the event were monitored and recorded by multiple GNSS continuous sta-tions.The results show that,afected by the M_(S)7.4 Maduo Farthquake some significant far-field co-seismic dis-placements were occured on the Xianshuihe fault along the southerm margin of the Bayan Har block.At the SHIQ station about 180 km away from the epicenter,the far-field co seismic displacement in the east-west direction reached as 8.8±2.4 mm,whereas the far field co-seismic displacement in the north-south direction reached as 2.5±2.3 mm.Through the analysis of the characteristics of the far-field co-seismic displacement field,we suggest that the horizontal co seismic displacement on the Xianshuihe fault along the southern margin of Bayan Har block gener-ated by the M_(S)7.4 Maduo earthquake gradually attenuated from west to east.