The electroseismic effect manifests itself as an electrical potential generated in the subsurface by the passage of seismic waves. It can be detected at the surface of the ground with electrode pairs. The time of occurrence of the voltage clearly distinguishes the effect from either the ionization potential produced at the time of explosion or the seismic electric effect produced coincident with the arrival of seismic waves at the surface of the ground.
Evidence is presented which associates the electroseismic effect with the base of the weathered layer and demonstrates its characteristics in several areas and at various distances from the shotpoint. Its immediate utility appears to be that of determining the travel time through the weathered layer at the shotpoint.