用最大熵谱法分析玉门地震序列的频谱变化

Analysis on the Spectrum Variation of Yumen Earthquake Sequence by Using Maximum-entropy Method

摘要:

采用Burg最大熵谱分析方法对玉门地震序列进行了频谱分析计算。结果显示:当主震发生时,频谱主频向高频方向变化,当整个序列接近尾声时,频率逐渐恢复。这个结果可解释为,随着应力的积累,孕震区介质部分裂隙闭合,挤出裂隙水,密度相对增大,品质因数提高,高频成分的衰减降低,使频谱的主频率移向高频。

Abstract:

In this paper the spectrum of Yumen earthquake sequence was calculated and analyzed by using the maximum-entropy method of Burg. The results showed that the dominant frequencies changed in direction to high frequencies with the coming of main shock, and the dominant frequencies gradually restored with the ending of sequence. This phenomenon could be understood as:with the accumulation of stress, some crannies across the earthquake-preparation zone were closed, then fluid in the crannies was pushed out, and density of the medium became relatively high, which made quality factor of the medium increase and attenuation of high-frequency components reduce so that dominant frequencies became higher.