基于小波分析提取地倾斜异常特征

Extraction of Ground Tilt Anormalies Based on Wavelet Analysis

利用小波分析方法在时间域和频率域具有较高分辨率的特性,选取db4小波基、细节6阶为各台站地倾斜整点值数据的研究对象,建立了小波分析异常提取方法。利用该方法提取了2011年以来新疆天山中段地区2次6级地震前地倾斜形变异常。结果表明,在MS≥6.0地震前,震中附近（〈300km）不同台站记录到了相同频段、周期的异常信号;异常主要集中在震中150~300km范围内,震中附近观测资料异常并不明显;不同方位台站对地震异常信号的接收时间具有一定指示意义。

Wavelet analysis possesses the characteristic of high resolution in time and frequency domains.We develop a method of extracting wavelet anomalies from ground tilt data using db4 wavelet packet and the 6-order detail.With this method,we have studied two earthquakes in middle area of Tianshan mountain in Xinjiang.The results show that the deformation stations in the region can record the same abnormal band information within 300 kilometers from the epicenter for magnitude 6or larger earthquakes.Anormalies mainly are concentrated in areas in the range of 150 to 300km.Stations at different azimuths play an important role for the starting times of ground tilt anomalies.