One possible generation mechanism of co-seismic electric signals

Abstract

A model considering the compensation of piezoelectric effect and the dislocation theory of fault is developed to investigate theoretically the generation of co-seismic electric signals. Charges are assumed to be induced by the stress changes associated with earthquakes. The stressinduced charges are quantified by the charge density as a function of the polarization, which can be calculated using a piezoelectric model and an analytical solution of seismic stress. The theoretical charge distribution around the Nojima fault, which moved at the 1995 Kobe earthquake (M=7.2), was obtained. The co-seismic electric field consistent with that observed at the Kobe earthquake was estimated as the field due to the charges, which compensated the piezoelectric charges.