HR: 08:20h
AN: S31C-02 INVITED     [Abstracts]
TI: A Wavelet Analysis Approach To Azimuth Estimation From Local Seismic Phases
AU: * Galiana-Merino, J
EM: juanjo@dfists.ua.es
AF: Dpto. Fisica, Ingenieria de Sistemas y Teoria de la Se¤al, Universidad de Alicante, Carretera de San Vicente del Raspeig s/n, San Vicente del Raspeig, Alicante, 03690 Spain
AU: Rosa-Herranz, J
EM: julio@dfists.ua.es
AF: Dpto. Fisica, Ingenieria de Sistemas y Teoria de la Se¤al, Universidad de Alicante, Carretera de San Vicente del Raspeig s/n, San Vicente del Raspeig, Alicante, 03690 Spain
AU: Jauregui-Eslava, P
EM: pedro.jauregui@ua.es
AF: Facultad de Ciencias, Universidad de Alicante, Carretera de San Vicente del Raspeig s/n, San Vicente del Raspeig, Alicante, 03690 Spain
AU: Molina-Palacios, S
EM: sergio.molina@ua.es
AF: Facultad de Ciencias, Universidad de Alicante, Carretera de San Vicente del Raspeig s/n, San Vicente del Raspeig, Alicante, 03690 Spain
AU: Giner-Caturla, J
EM: jj.giner@ua.es
AF: Facultad de Ciencias, Universidad de Alicante, Carretera de San Vicente del Raspeig s/n, San Vicente del Raspeig, Alicante, 03690 Spain
AB: We have developed a new approach for azimuth estimation in local three-component seismograms through wavelet analysis. The proposed method proceeds in three stages: First, raw seismograms are denoised through an approach based on the wavelet packet transform. Next, the denoised signal is decomposed using the discrete wavelet transform and expressed as a set of different signals (wavelet coefficients). According to the frequency content of the seismograms, we select one of these wavelet coefficients and apply a P-picker algorithm very similar to a short-term-average long-term-average scheme. In the last stage, we generate a new signal that it is a combination of selected wavelet coefficients, and an adaptative-length window around the pick is chosen. Finally, we calculate the azimuth and elevation angles using the data in this window. The proposed method has been applied to local three-component short-period seismograms recorded by the local seismic network of the University of Alicante, in southeastern Spain. The locations of these events were previously obtained through the software HYPO71PC (Lee and Valdes, IASPEI, 1989) and the seismograms recorded by four analog stations of vertical component distributed within the province of Alicante. The results obtained by the wavelet decomposition algorithm have been compared with the azimuth angles obtained through the results from the location software. The comparison indicates that the proposed method can determine the azimuth angle of the analyzed events within a standard deviation of 4.3§, which is lower than the uncertainty of our local array azimuth estimates for the same events.
DE: 7290 Computational seismology
SC: Seismology [S]
MN: Fall Meeting 2005