A phase plane method for the analysis of seismic signals

In explosion seismology, computer detection of reflected waves is the most important process in relating seismograms to subsurface structure. In this paper the analysis of the complex oscillations of the seimometers is undertaken in the phase plane. The variations of the "phase plane velocity", defined as the velocity of the point moving along the phase trajectory, reflect the changing properties of a dynamic model of the seismic signal. A procedure is presented that determines the arrival times of the waves by segmenting the signals into intervals where the "phase plane velocity" tends to vary in a monotonic manner. Field results show that the arrival times can be precisely identified.