METHOD FOR PASSIVE LOCATION OF SEISMIC SOURCES.

This paper discusses a methodology useful in locating sources of influences in a medium, whether they are considered to be ″signals″ or ″noises″ . It also presents results of measurement of the coherence, across a geophone array, of seismic signals generated by a moving six-ton truck. The phase fronts of waves emanating from a source through a medium have been shown to be sufficiently uniform over contiguous sectors of the propagating wave fronts to provide useful source location parameter estimates. This is presumed to be true for each layer of a stratified medium. However, the phase fronts from different layers may interfere and obscure the source location information. The technique reported here uses samples of the field produced by the sources obtained from a remote array of sensors. Operations on these samples of the field, carried out in the frequency domain, reveal the source location parameters. Refs.