Russian Journal of Earth Sciences
Papers in press
Modelling of seismo-electromagnetic phenomena
Naum Gershenzon and Gust Bambakidis
Abstract
A model for seismo-electromagnetic (SEM) phenomena is described. The electromagnetic signals
generated by mechanical disturbances in the earth's crust have been calculated and compared
with reported seismo-electromagnetic signals (SEMS). The major known SEM phenomena, namely,
tectonomagnetic variations, electrotelluric anomalies, geomagnetic variations in the ultra-low
frequency range and electromagnetic emission in the radio frequency range, have been considered.
We have calculated the spectral densities associated with various types of sources. The set of
formulas necessary to calculate the detected (filtered and averaged) electric and magnetic fields
generated by mechanical disturbances for a wide range of frequencies and at various distances
from the source are presented. Based on these formulas, we discuss the conditions under which
electro-kinetic, piezo-magnetic and piezo-electric effects could be responsible for SEMS.
A comparison of estimated values of SEMS with reported field measurements leads to the conclusion
that the sources of most anomalous SEMS are relatively close to the detector. In other words,
the source of the signal is local, although the source of the mechanical disturbance which
activates it, i.e. the epicenter of an earthquake, may be far away. Recommendations for field
experiments (appropriate detector sitting, detector parameters and frequency range) following
from the model developed here are presented.