首都圈中强震前后视应力时空演化过程研究

Temporal-spatial Evolution of Apparent Stresses before Moderate-strong Earthquakes in the Capital Circle Area of China

选用首都圈数字遥测地震台网地震波形资料,利用近震源Brune模式计算首都圈地区2002年至今ML≥2.0地震的视应力值,探讨了震源参数的标度关系,最终选取2.0≤ML≤2.9地震对首都圈地区2002年以来中强地震前视应力的时空异常变化特征进行详细分析。研究结果表明:首都圈中强地震前,多次地震出现显著的视应力高值异常,且地震多发生在视应力高值异常区域附近。同时与波速比计算结果进行了对比分析,印证了异常存在具有一定的客观性。由此可见,分析识别首都圈地区的应力状态可以为该地区中强震的危险性提供判定依据。

Using the near-source Brune model,we calculate apparent stresses of ML≥2.0earthquakes occurred in the capital area of China since 2002 using seismic waveform data recorded by the Capital Circle Digital Seismic Network.We discussed scaling relations of source parameters,and choose the 2.0≤ML≤2.9earthquakes to analyze and discuss anomalous variation characteristics in time and space before medium-strong earthquakes.The results show that apparent stresses have an obvious high value anomaly before many medium-strong earthquakes,and the earthquakes occurred at high value anomaly area.It can be seen that apparent stress state of can provide evidence for seismic risk analysis in the capital region.