سید رضا منصوری

The determination of P and S waves arrival times is important for a variety of seismological applications including earthquake location and seismic tomography . Quickly detecting and accurately picking the first P wave arrivals are of great importance in event location , event identification , and source mechanism analysis , especially in the era of large volumes of digital and real-time seismic data . Manual analysis of seismograms and phase picking is time-consuming and subjective . Various techniques have been presented in the literatures for detecting and picking the arrivals of different seismic phases from single-component as well as three-component recordings . In this study the wavelet transform has been used to detect and pick the arrival of compressional phases since it is suitable for analysis of non-stationary signals in multi-scale format . In order to detect the Pwave arrival , the wavelet coefficients are calculated using the vertical component of the seismogram . In this study the P arrival time was determined by using the envelope of the wavelet coefficients and edge detection