摘要
采用地震波初动半周期估算应力降的方法 ,计算了张北震区 2 5次较大地震的应力降并对余震的应力降进行了分析 ,2月 2 3日震区内发生的 ML3.5级地震 ,其应力降高达2 6.2× 1 0 5Pa,为 3月 1 1日 5.6级地震的震前异常。
Using the method to estimate stress drop with the semiperiod of seismic wave's first motion,we calculated the stress drop of 25 larger earthquakes in Zhangbei earthquake area,and analyzed the stress drop of after shocks.The stress drop of the M L3.5 earthquake occurred on February 23 was high to 26.2×10 5Pa.This anomaly can be regarded as the precursor of March 11's Ms5.6 earthquake.
出处
《华北地震科学》
2000年第2期66-69,共4页
North China Earthquake Sciences
