Detection of wave reflectors and wave sources in the earth subsurface

Event detection is a very important task in geophysics. It encompasses the detection of wave sources (earthquakes, subsurface explosions) and the detection of wave reflectors (interfaces between rock layers having different velocities and/or different densities). The latter application is very important in seismic oil prospecting. Seismic events release energy which propagates toward the earth surface as waves which are recorded by arrays of sensors. The data recorded are usually corrupted by noise, which sometimes is much stronger than the weak events. The aim of this paper is to couple wave theory and detection theory to detect seismic events in an optimal way. A statistical model of the earth is proposed. This model combined with the wave equation describes sufficiently well the wave propagation in the stratified earth. Optimal and suboptimal receivers for event detection, based on this earth model, are proposed. The validity of our approach is demonstrated by simulation examples.