Description of seismic events using wavelet transform
This paper deals with engineering application of wavelet transform for processing of real seismological signals. Methodology for processing of these slight signals using wavelet transform is presented in this paper. Briefly, three basic aims are connected with this procedure: 1. Selection of optimal wavelet and optimal wavelet basis B-opt for selected data set based on minimal entropy: B-opt = axg min(B) E(X, B). The best results were reached by symmetric complex wavelets with scaling coefficients SCD-6. 2. Wavelet packet decomposition and filtration of data using universal criterion of thresholding of the form lambda = sigma root 2 ln(n), where sigma is minimal variance of the sum of packet decomposition of chosen level. 3. Cluster analysis of decomposed data. All programs were elaborated using program MATLAB 5.
wavelet transform time frequency spectra seismological data