Study on the generation mechanism of Co-seismic electric signals

An electromagnetic fault model, which considered the compensation of piezoelectric effect and the dislocation theory of fault, was presented to deal with the reported co-seismic electric signals. Charges are assumed to be induced by the stress changes associated with an earthquake. The stress-induced 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 compensate the piezoelectric charges. ? 2004 IEEE.EI