基于经验模态分解方法的山西断裂带跨断层形变资料分析

Analysis of Shanxi Fault Zone Cross-Fault Deformation Observation Data Based on Empirical Mode Decomposition

利用经验模态分解方法重构并提取山西断裂带跨断层形变监测高频平稳信号和低频趋势信号。基于高频平稳信号分析地震前兆异常及其表现形式,结果表明,在山西断裂带及邻近地区中强地震前部分跨断层测段出现明显异常;强震前山西断裂带跨断层异常测点数量多、分布广、距离震中较远,中强地震前异常测点多集中在震中附近。基于低频趋势信号分析断层形变时空分布特征表明,山西断裂带断层以继承性正断运动为主,断层分时分段差异特征明显。

We reconstruct and extract the high-frequency stationary signals and low-frequency trend signals of Shanxi fault zone cross-fault deformation observation data using empirical mode decomposition(EMD).We analyze the earthquake precursory anomalies and their manifestations based on the high-frequency stationary signals reconstructed,and the results show that notable omen anomalies appear before the moderate-strong earthquakes occurred in Shanxi province and its adjacent areas.While there are a great number of abnormal sites before the strong earthquakes in the adjacent areas,which are widely spread and far from the epicenters,the abnormal sites before the moderate-strong earthquakes in Shanxi province concentrate close to the epicenters.We analyze the spatio-temporal evolution characteristics of fault deformation based on the low-frequency trend signal reconstructed,and the results show that the faults in Shanxi fault zone are dominated by inherited positive fault movement,but the fault movement characteristics vary by place and time.