2018年通海两次5.0级地震前GNSS观测异常及震后云南地区的应变变化

基于2018-01以来云南地区GNSS连续观测时间序列,采用克里金插值方法对形变场进行网格化、计算应变,并获取面应变,结合基线数据动态分析两次通海5.0级地震前区域应变场特征和震后云南地区的应变变化情况。结果表明,通海地震前,云南整体区域应变积累存在显著增强的背景,并在震前短期内出现快速反向调整;通海地震后,短期内以腾冲为代表的小滇西地区、大寨-会泽等滇东北地区挤压应变积累出现明显的减弱趋势,滇南地区的勐海-勐腊区域存在压性增强现象。

GNSS Observation Anomalies before the 2018 M5.0 Earthquake in Tonghai and Subsequent Strain Changes in Yunnan

Based on the continuous observation time series of GNSS in Yunnan since January 2018, the Kriging interpolation method is used to mesh the deformation field, the strain calculation is performed, and the surface strain is obtained. Based on baseline data, the characteristics of the regional strain field before the Tonghai M5.0 earthquake and the strain changes in the Yunnan area after the earthquake are analyzed. The results show that before the Tonghai earthquake, the overall regional strain accumulation in Yunnan has a significantly enhanced background, and a rapid reverse adjustment occurs in the short term before the earthquake. After the Tonghai earthquake, in the short-term, the squeezing strain accumulation has obviously weakened for the Dazhai-Huize areas in northeastern Yunnan and the near areas of Tengchong. There is a pressure-enhanced phenomenon in the Menghai-Mengla area of southern Yunnan.