Seismic noise study for accurate P-wave arrival detection via MODWT

The arrival timing of the onset of microseisms and weak events is difficult to be picked even manually. The proposed algorithm uses the maximal-overlap discrete wavelet transform (MODWT) to perform manual detection for such weak events. A seismic noise analysis was done to choose the best criteria for showing clear P-wave arrival. This algorithm is also used as an accurate automatic P-wave picking algorithm. The noise level at a seismic station does not affect the proposed picking algorithm because it adapts itself to the noise level in front of each earthquake. Local events recorded by the Egyptian National Seismic Network (ENSN) were used to test this proposed algorithm. The overall average error was found to be 0.02 s.

► P-wave picking is the first step in seismic signal analysis.
► Studying the seismic noise is a key point in making the algorithm.
► MODWT is used because it does not suffer from start point choice.
► Small detection error could be achieved.