摘要
地震波在地球内部四处传播,向大气辐射次声波,称为地震次声波.次声波频率在20Hz以下,振幅衰减小,传播距离远,在大气声道中(从地面到50km的高空)可以传播上千km,有的绕地球数周后仍能被探测到.因此次声波与地震有很好的对应关系,一般情况下世界范围内7级以上地震在震前能观测到次声波异常信号.利用高性能电子计算机和日益完善的信号分析处理技术,找出震前次声波异常信号的内在特征。为以后的地震预报提供重要的参考价值.对地震前接收到的次声波异常信号数字离散化,运用傅里叶变换和小波分析理论对信号进行处理,发现震前接收到的次声波异常信号频率主要集中在0～4×10-3Hz频段,该信号在高尺度段表现出对称有序性,在低尺度段突变明显.
When the weave of earthquake spreads out in the earth, it can radiate the infrasound. The kind of infrasound is called as earthquake infrasound. The frequency of infrasound is under the 20 Hz, it＇s magnitude is declined slowly, and at the same time it spreads far. The infrasound can spread several kilometers long in the air （from the earth＇s surface upper to the 50 kilometers）. The infrasound can be detected after circling the earth several weeks. Because of these characters, the infrasound has the good opposite connection with the earthquake. As a rule, the abnormal infrasound signal can be detected beyond the magnitude 7 of earthquake in the world. Using the good capabilities of computer and the more and more perfect technologies of signal analysis to find out the inside qualities of infrasound abnormal signal before the earthquake, which will provide the important value for forecasting the earthquake later. Using the discrete Fourier transform and wavelet theories, the abnormal signal is found and it＇s range of frequency is about from 0 Hz to 4 × 10^-3 Hz after the abnormal signal is discrete, at the same time the abnormal signal is symmetrical and regular in higher scale and the abnormal signal is broken in lower scale.
出处
《北京工业大学学报》
CAS
CSCD
北大核心
2005年第5期461-465,共5页
Journal of Beijing University of Technology
关键词
次声波
信号分析处理
地震预报
infrasound
analysis of signal
earthquake forecast
