地震波拐角频率对地震序列的依赖性研究

使用皎口、海城、陡和、浑源等地震序列的地震波记录，研究了拐角频率随地震序列进程的变化特征。为了消除地震震级对拐角频率趋势性变化的影响，求得了每个地震的拐角频率与序列中同震级地震拐角频率的比值随地震序列发展而变化的曲线，较好地反映出该比值的发展进程；即在一个前一主一余地震序列中，同震级前震拐角频率高于余震拐角频率；而对震群地震序列则看不出这种变化。利用地震序列外围地区适当范围小震资料的拐角频率作为背景值，其比值曲线同样很好地反映出地震序列发展的规律。本方法可以作为对地震序列发展趋势进行较客观评估的新方法。

STUDY ON SEISMIC WAVE CORNER FREQUENCY DEPENDING ON EARTHQUAKE SEQUENCES

Using waveform data of Jiaokou, Douhe, Hunyuan and Haicheng earthquake sequences, the characteristics of corner frequency changing with the earthquake process is studied. In order to remove the magnitude affects which imposed on the corner frequency change trend, we obtain the ratio curves of corner frequency values in every event to corner frequency mean values with equal magnitudes in the same earthquake sequence.The curve shows the ratio changing process clearly:in the foreshock-aftershock pattern sequence, the corner frequency of foreshock is higher than that of aftershock if their magnitudes, are equal, but in swarm sequence this trend is not show.Using the mean value of corner frequency from small events in a larger area as the background value,we obtain the ratio curve which reflect the changing process of earthquake sequence also clearly. The method which gives the changing trend in a earthquake sequence could be a new way for earthquake prediction.