Dielectric properties of Granodiorite partially saturated with water and its correlation to the detection of seismic electric signals

TL;DR

This study investigates the dielectric properties of granodiorite from a seismically sensitive site, revealing a negative activation volume that supports models linking rock electrical behavior to pre-earthquake signals.

Contribution

It provides the first laboratory evidence of negative activation volume in granodiorite, supporting theories connecting dielectric response to seismic electric signals.

Findings

Negative activation volume observed in granodiorite

Supports correlation between dielectric properties and seismic signals

Laboratory results align with theoretical models

Abstract

Transient electric signals emitted prior to earthquake occurrence are recorded at certain sites in the Earth's crust termed sensitive. These field observations enforce the laboratory investigation of the dielectric response of rocks forming these localities. The dielectric relaxation of granodiorite rock coming from such a sensitive locality (Keratea, Greece) reveals, through complex impedance spectroscopy, that the activation volume for relaxation of this rock is negative which so far has been reported only rarely. This result, however, supports a theoretical model on the pre-seismic electric signals and is likely to be correlated with the sensitivity of the site and hence with the selectivity.