大地震前近台背景噪声的频谱分析

选取了2008年汶川地震发生前12天四川测震台网震中附近三个台和2010年玉树地震前14天青海测震台网震中附近三个台的地震仪连续记录进行功率谱密度的分析。结果表明,近台背景噪声频谱与其它台站的记录存在差异,并且两次大地震的近台记录特征具有相似性。这种特征表达了震源区的岩层活动的物理过程与其后发生的大地震是有关联的。这些信息的提取和研究有助于对构造性地震的发震机理研究以及地震预报的探索。

Analysis on the Spectrum of Background Noise in Stations near by Epicenters of Two Great Earthquakes

The continuous recorded broadband seismographics waveform data in 12 days before the Wenchuan M8.0 earthquake in 2008 from 3 seismic stations of Sichuan digital seismic network and one in 14 days before the Yushu M7.1 earthquake in 2010 from 3 seismic stations of Qinghai digital seismic network, which nearby the epicentres, are chosen and analyzed. The result shows that dominant frequence of background noise obvious changed before the two main rupure, and both cases have similar character. It indicated possible slight ruputures in the seismogenic zone before the great earthquake. Althougt it is a primary result, it is helpful to research induction machinism of earthquake and earquake prediction explore.