基于GNSS应变时序的云南地区构造运动与地震事件孕震模式分析

Analysis of Seismogenic Modes of Tectonic Movement and Earthquake Events in Yunnan: Based on GNSS Time Series of Strain Anomalies

基于2011年以来云南地区59个GNSS测站的连续观测资料,计算面应变异常网格变化的时间序列,结合异常格网所在区域的动力学和地质构造背景、断层活动特性及震源机制等对区域异常的时空分布特征及地壳形变异常与地震事件之间的关系进行综合分析,并以2013-08-28发生的5.1级德钦地震为例验证基于应变时序孕震分析方法的有效性。结果表明,在宏观分析区域面应变长期背景特征的基础上,基于区域断裂活动性质和应变时间序列分析探讨面应变短期异常与地震事件之间关系的分析方法具有一定的科学合理性,能够在地震发震前夕得到有效的预报信号。

Based on continuous observation data from 59 GPS stations in Yunnan since 2011,the time series of surface strain anomaly mesh changes is obtained.The dynamics and geological tectonic background of the anomalous grid region,the characteristics of fault activity,and the type of focal mechanism of earthquake events are combined to analyze the spatial and temporal distribution characteristics of regional anomalies,as well as the relationship between crustal deformation anomalies and seismic events.The Dêqên earthquake is used as a seismic case to verify the effectiveness of the seismometric analysis method based on strain sequences.The results show that,based on the long-term background characteristics of the surface strain in the macroscopic analysis,the analysis method of the relationship between the short-term anomaly of surface strain and the earthquake event based on the nature of regional fault activity,that the strain time series analysis has certain scientific rationality.Possibly,for some earthquakes such as the Dêqên earthquake,there were effective predictive signals on the eve of the earthquake.