【摘要】 基于前人整理的"前驱波"特征和小波变换理论,应用小波方法分析了2001年11月14日昆仑山口西MS8.1和2004年12月26日苏门答腊MS8.7地震前30天山东泰安台体应变观测分钟值的高通滤波数据。研究表明,在昆仑山口西MS8.1地震前,高通滤波数据和小波分析结果比较正常。苏门答腊MS8.7地震前,高通滤波数据呈与气压相关变化,无明显异常,但小波分析结果细节部分第1、2层在12月5日左右有类似"前驱波"信号出现,波幅变化在±0.5×10-9之间,主要周期成分在2～4分钟之间,持续时间1天左右,与同时段气压变化形态不一致,对这种异常现象需要做进一步的分析。小波变换能够提取出体应变资料中的微弱变化信号,是检验强震"前驱波"的一种有效方法。更多还原

【Abstract】 Based on precursor characteristics and wavelet transform theory,in order to check-up the precursors before the KunLun MS8.1 earthquake on November 14,2001 and Sumatra MS8.7 earthquake on December 26,2004,we apply wavelet transform method to analyze the high-pass filtered data,which was recorded at a sampling interval of 1 minute by Tai’an station,Shan-Dong province,of in the 30 days before earthquake.The research results indicate that there were not anomaly changes during the 30 days before the KunLun MS8.1 earthquake.Before Sumatra MS 8.7 earthquake,there were neither anomaly changes in high-pass filtered data,but a precursor-like signal exists in the detailed decomposing decomposed signals of wavelet when the scale equals to 1,and 2,which appeared on December 5,with amplitude change between ±0.5×10-9 and period between 2～4 minute,.The signal is not coincident with air pressure change.We should pay attention to and thoroughly analyze this kind of phenomenon.Therefore,wavelet transform can be used to identify the two-by-twice change existed in deformation signal,which is an effective method to check-up precursors before strong earthquakes.更多还原