Robust arrival time determination of seismic waves in noise

In explosion seismology, the arrival time determination of reflected waves is the fundamental problem in relating seismograms to the subsurface structure. A robust method, combining both energitical and zero-crossings analyses of the signal, is proposed. The basic idea is to analyse the variations of the signal power computed between consecutive zero-crossings. In order to handle noisy signals, discrimination of the effects of noise on the so-computed power is performed by means of an unsupervised automatic classification procedure. Synthetic signals and field data, recorded in the south of Morocco, have been used to illustrate the performance of the procedure.