Automatic Earthquake Signal Onset Picking Based on the Continuous Wavelet Transform

This paper presents a method for automatic earthquake signal phase picking based on the continuous wavelet transform (CWT) of the seismogram, namely, the wavelet phase picker (WPP). A characteristic function is defined using the envelope function of CWT coefficients of the vertical component seismogram. The performance of the WPP method is evaluated on a database consisting of more than 460 local seismograms, and the P-phases detected by the algorithm are compared with those reported in the database. This evaluation confirms the high accuracy of automatically detected picks for the majority of seismograms. In addition, the results obtained by the algorithm are compared with a well-known method of P-phase picking referred to as the autoregressive Akaike information criteria. This comparison demonstrates the reliability of the proposed method.