Automatic P-Phase Picking Based on Local-Maxima Distribution

In this paper, we propose a method for the automatic 4 identification of P -phase arrival based on the distribution of local 5 maxima (LM) in earthquake seismograms. The method efficiently 6 combines energy and frequency characteristics of the LM distri7 bution (LMD). The P detection is mainly based on the energy of 8 a seismic event in the case the earthquake has higher amplitude 9 than seismic background noise. Otherwise, it is based on the 10 frequency of LM. Thus, the method provides robust detection of 11 P -phase arrival in any quality type of seismic data. Moreover, 12 it uses two sequential sliding signal windows yielding very high 13 accuracy on the P -phase estimation. A hierarchical P -phase 14 detection algorithm dramatically reduces the computational cost, 15 making possible a real-time implementation. Experimental results 16 from a large database of more than 80 low, medium, and high 17 signal-to-noise ratio seismic events and comparison with existing 18 methods in the literature indicate the reliable performance of the 19 proposed scheme. 20