Review Article
Petraki E, Nikolopoulos D, Nom
Abstract
This paper is a survey of pre-earthquake short-term electromagnetic precursors. Extensive studies were carried out the last decades in analysis of electromagnetic emissions from 10-3 Hz up to MHz. These signals were analyzed through visual, statistical and chaotic techniques. The paper presents cumulative elements from scientific investigations performed during the last 40 years in this area. Physical models have also been developed for the interpretation of production and propagation of electromagnetic radiation during the fracture process. The Ultra Low Frequency (ULF) fracture-re-lated emissions attempted to be explained via magneto-hydrodynamic, piezomagnetic and electroki-netic effects whereas for the kHz-MHz observations the model of asperities was proposed.