EXOELECTRON EMISSION - POSSIBLE RELATION TO SEISMIC GEOELECTROMAGNETIC ACTIVITIES AS A MICROSCOPIC ASPECT IN GEOTRIBOLOGY

The present study investigates the source mechanism of the seismic geo-electromagnetic activities that occur in a geotribosystem. It was shown that granite generates thermally stimulated exoelectron emission (TSEE) at temperatures ranging from 300 to 400-degrees-C. This emission is released from the trapped levels at intrinsic and extrinsic centres in the minerals. Possible heat sources are discussed in terms of the frictional heating of the precursor slip. Fracture-induced transient electric signals (FTESs), propagated through the rock, could be detected; the intensity of the signals decayed inversely proportionally to the distance from the fracture zone. Less FTES was detected for granite annealed at a temperature of 400-degrees-C, where the piezoelectric effect was unchanged but the exoelectron sites were reset. This confirms that the main source of FTES and seismic geo-electric activity is probably the trapped electrons.