Evidence of fractional-Brownian-motion-type asperity model for earthquake generation in candidate pre-seismic electromagnetic emissions

Abstract

Abstract. Many aspects of earthquake generation still escape our full understanding. Observations of electromagnetic emissions preceding significant earthquakes provide one of the few cases of premonitory events that are possibly related to a subsequent earthquake. Understanding the factors that control electromagnetic precursors generation seems to be important for determining how significant earthquakes nucleate. Here we report the results of a comprehensive study of the appearance of individual patterns in candidate electromagnetic precursors possibly indicating the breaking of backbone of large and strong asperities that sustain the activated fault. The search of precursory patterns is mainly based on well documented scaling properties of fault surface topology. More precisely, we argue that the candidate electromagnetic precursors might be originated during the slipping of two rough and rigid fractional-Brownian-motion-type profiles one over the other, with a roughness which is consistent with field and laboratory studies. The results also imply that the activation of a single earthquake (fault) is a reduced selfaffine image of the whole regional seismicity and a magnified self-affine image of the laboratory seismicity.

Fractal Analysis of Pre-Seismic Electromagnetic and Radon Precursors: A Systematic Approach

“…The pre-seismic traces may unfold with fractal methods [3,6,8,9,11,14,16,17,43,44,52,[55][56][57][58]61,84]. These seismic systems evolve naturally into self-organised critical (SOC) states with fractal organisation in space and time [4].…”

“…In general, it is well accepted that electromagnetic phenomena are detectable before the occurrence of earthquakes [3,4,9,10,18]. [5] reported that several seismogenic phenomena have already been found from direct current (DC), ULF up Figure 2 with the corresponding lettering in bold red.…”

“…The EM seismic precursors include ultra-low frequencies (ULF) from 0.001 to 1 Hz [1][2][3][4][5][6][7], low frequencies (LF) from 1 to 10 kHz [6,[8][9][10][11][12][13], high frequencies (HF) from 40 to 60 MHz [6,8,[14][15][16][17] and very high frequencies (VHF) up to 300 MHz [18]. A key strategy for recognising the EM pre-earthquake precursors is the direct detection of EM radiation emission from the lithosphere [5].…”

“…As indicated by researchers [10,11,19], these principal transmitters are the dynamically unstable multi-cracks that are continuously generated and moved during the earthquake preparation process. It is the movement of the cracks that causes the fragment of the ionic bonds at the surfaces of new small scale cracks and brings out the surface-charge division which transforms the smaller scale cracks into effective electric dipoles and electromagnetic emitters before seismic events [9][10][11]20,21]. Therefore, the study of EM precursors is a significant step towards reliable earthquake prediction.…”

Recent seismic activity at Cephalonia (Greece): a study through candidate electromagnetic precursors in terms of non-linear dynamics

“…The possible relation of the field-observed fracture-induced electromagnetic emissions (EME) in the frequency bands of MHz and kHz, associated with shallow EQs with magnitude 6 or larger that oc-curred inland or near the coast, has been examined in a series of publications in order to contribute to a better understanding of the underlying processes (e.g. Eftaxias et al, 2001Eftaxias et al, , 2004Eftaxias et al, , 2008Kapiris et al, 2004;Karamanos et al, 2006;Papadimitriou et al, 2008;Contoyiannis et al, 2005Contoyiannis et al, , 2013Potirakis et al, 2011Potirakis et al, , 2012aPotirakis et al, , b, c, 2013Potirakis et al, , 2015Minadakis et al, 2012a, b;Balasis et al, 2011Balasis et al, , 2013Donner et al, 2015;Kalimeris et al, 2016). Additionally, a four-stage model for the preparation of an EQ by means of its observable EM activity has been recently put forward Contoyiannis et al, 2015, and references therein).…”