Pre-earthquake signals – Part II: Flow of battery currents in the crust

Abstract

Abstract. When rocks are subjected to stress, dormant electronic charge carriers are activated. They turn the stressed rock volume into a battery, from where currents can flow out. The charge carriers are electrons and defect electrons, also known as positive holes or pholes for short. The boundary between stressed and unstressed rock acts as a potential barrier that lets pholes pass but blocks electrons. One can distinguish two situations in the Earth's crust: (i) only pholes spread out of a stressed rock volume into the surrounding unstressed rocks. This is expected to lead to a positive surface charge over a wide area around the future epicenter, to perturbations in the ionosphere, to stimulated infrared emission from the ground, to ionization of the near-ground air, to cloud formation and to other phenomena that have been reported to precede major earthquakes. (ii) both pholes and electrons flow out of the stressed rock volume along different paths, sideward into the relatively cool upper layers of the crust and downward into the hot lower crust. This situation, which is likely to be realized late in the earthquake preparation process, is necessary for the battery circuit to close and for transient electric currents to flow. If burst-like, these currents should lead to the emission of low frequency electromagnetic radiation. Understanding how electronic charge carriers are stress-activated in rocks, how they spread or flow probably holds the key to deciphering a wide range of pre-earthquake signals. It opens the door to a global earthquake early warning system, provided resources are pooled through a concerted and constructive community effort, including seismologists, with international participation.

Advances in understanding of the mechanism for generation of earthquake thermal precursors detected by satellites

“…A mechanism of strong low frequency electromagnetic emission has been proposed by Freund and his co-workers through a solid-state physics viewpoint (Freund, 2002(Freund, , 2003(Freund, , 2007Freund et al, 2005). The proposed mechanism combines the critical earthquake concept of crust acting as a charging electric battery under increasing stress.…”

Non-inductive components of electromagnetic signals associated with L'Aquila earthquake sequences estimated by means of inter-station impulse response functions

“…Another generation mechanism of signal emission proposed by Varotsos and Alexopoulos are the PSPC (Pressure Stimulated polarization Currents), (Varotsos et al, 1993(Varotsos et al, , 1998, (Uyeda et al, 2009). Another interesting model of generation of electric current was proposed by Freund and his co-workers (Freund, 2002(Freund, , 2003(Freund, , 2007 named P-Holes theory which took strong low frequency electromagnetic emissions reported in other published papers into account. Kopytenko et al (1993) and Johnston (1997) show that the detection of seismogenic signals in the extreme frequency band would require however surface measurement systems to be very close to the epicenter of the earthquake.…”

Influences of Solar Cycles on Earthquakes

“…Freund and Hermance [7][8][9], showed different sources of electrical charges generated by rocks. The first aim of this research is to find out the possible connections between the sunspot variations and their influence on the earthquakes.…”