Electromagnetic Signature of Prefracture Criticality in Heterogeneous Media

Kapiris, P.; Eftaxias, K.; Chélidzé, T.

doi:10.1103/physrevlett.92.065702

Cited by 87 publications

(163 citation statements)

References 29 publications

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“…Their lead time is ranged from a few days to a few hours. Importantly, the MHz radiation precedes the kHz one at geophysical scale, as well (Eftaxias et al, 2002;Kapiris et al, 2004a;Contoyiannis et al, 2005). Notice that a complete sequence of SES, MHz and kHz EM anomalies have been observed one after the other in a series of significant EQs that occurred in Greece (Eftaxias et al, 2000(Eftaxias et al, , 2002Karamanos et al, 2006;Papadimitriou et al, 2008).…”

Section: Figmentioning

confidence: 96%

“…We recall that an important feature, observed both on laboratory and geophysical scale, is that the MHz radiation precedes the kHz one (Eftaxias et al, 2002 and references therein). Recently, we proposed that the pre-earthquake MHz and kHz EM anomalies obey the following two-stage model (Kapiris et al, 2004a;Contoyiannis et al, 2005;Eftaxias et al, , 2007bPapadimitriou et al, 2008).…”

Section: A Two Stages Model Of Eq Preparation In Terms Of Mhz-khz Em mentioning

confidence: 99%

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Unfolding the procedure of characterizing recorded ultra low frequency, kHZ and MHz electromagnetic anomalies prior to the L'Aquila earthquake as pre-seismic ones - Part 2

Eftaxias¹,

Athanasopoulou²,

Balasis³

et al. 2010

Nat. Hazards Earth Syst. Sci.

147

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Abstract. Ultra low frequency-ULF (1 Hz or lower), kHz and MHz electromagnetic (EM) anomalies were recorded prior to the L'Aquila catastrophic earthquake (EQ) that occurred on 6 April 2009. The detected anomalies followed this temporal scheme. The question effortlessly arises as to whether the observed anomalies before the L'Aquila EQ were seismogenic or not. The main goal of this work is to provide some insight into this issue. More precisely, the main aims of this contribution are threefold: How can we recognize an EM observation as pre-seismic one? We aim, through a multidisciplinary analysis to provide some elements of a definition. How can we link an individual EM anomaly with a distinctive stage of the EQ preparation process? The present analysis is consistent with the hypothesis that the kHz EM anomalies were associated with the fracture of asperities that were distributed along the L'Aquila fault sustaining the system, while the MHz EM anomalies could be triggered by fractures in the highly disordered system that surrounded the backbone of asperities of the activated fault. How can we identify precursory symptoms in an individual EM precursor that indicate that the occurrence of the EQ is unavoidable? We clearly state that the detection of a MHz EM precursor does not mean that the occurrence of EQ is unavoidable; the Correspondence to: K. Eftaxias (ceftax@phys.uoa.gr) abrupt emergence of kHz EM emissions indicate the fracture of asperities. The observed ULF EM anomaly supports the hypothesis of a relationship between processes produced by increasing tectonic stresses in the Earth's crust and attendant EM interactions between the crust and ionosphere. We emphasize that we attempt to specify not only whether or not a single EM anomaly is pre-seismic in itself, but mainly whether a combination of emergent ULF, MHz and kHz EM anomalies could be characterized as pre-earthquake.

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Section: Figmentioning

confidence: 96%

Section: A Two Stages Model Of Eq Preparation In Terms Of Mhz-khz Em mentioning

confidence: 99%

Unfolding the procedure of characterizing recorded ultra low frequency, kHZ and MHz electromagnetic anomalies prior to the L'Aquila earthquake as pre-seismic ones - Part 2

Eftaxias¹,

Athanasopoulou²,

Balasis³

et al. 2010

Nat. Hazards Earth Syst. Sci.

147

View full text Add to dashboard Cite

show abstract

“…These precursors are detectable both at a laboratory and a geophysical scale. It is by now recognized that the pre-fracture kHz-MHz EM time series contain valuable information about the fracture EQ preparation process (Kapiris et al, 2004;Karamanos et al, 2005Karamanos et al, , 2006. Being non-destructive, monitoring techniques based on these fracture-induced fields are a basis for a fundamental understanding of fracture mechanism and for development consecutive models of rock/focal area behavior.…”

Section: Introductionmentioning

confidence: 99%

Tsallis and Levy statistics in the preparation of an earthquake

Contoyiannis

Eftaxias

2008

Nonlin. Processes Geophys.

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Abstract. Precursory fracture induced electromagnetic (EM) emissions, rooted in opening cracks and ranging from MHz to kHz, with the MHz appearing earlier, are produced and detected both at laboratory and geophysical scale. Recently, we have proposed the following two epochs/stages model of EQ generation: (i) The final kHz part is triggered by the fracture of high strength and large asperities that are distributed along the activated fault and sustain the system. (ii) The initial MHz part is thought to be due to the fracture of highly heterogeneous system that surrounds the family of asperities. Interestingly, the MHz EM time-series can be described in analogy with a thermal second order phase transition. Herein we focus on the MHz pre-seismic activity, and especially on the naturally arising question: what is the physical mechanism that organizes the heterogeneous system in its critical state? Combining ideas of Levy and Tsallis statistics and criticality with features hidden in the precursory MHz time-series we argue that a Levy walk type mechanism can organize the heterogeneous system to criticality. Based on a numerically produced truncated Levy walk, we propose a way to estimate in the stage of critical fluctuations: (i) the associated Levy index-a, which describes quantitatively the underlying Levy dynamics, and (ii) the range of values where the nonextesitive Tsallis index q is restricted. We also show that the kHz EM activity could not be described by a truncated Levy mechanism. This result further indicates an abrupt sweep of the population of asperities that sustain the system.

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“…Some reports including the magnetic field data, are Hayakawa et al (1999Hayakawa et al ( , 2000; Smirnova et al (2001);Telesca et al (2001);Gotoh et al (2003), Ida et al (2005); Ida and Hayakawa (2006) and for the electric signals, Ramirez-Rojas et al (2004a, b); Varotsos et al (2002Varotsos et al ( , 2003a; Kapiris et al (2003Kapiris et al ( , 2004.…”

Section: Introductionmentioning

confidence: 99%

A statistical analysis of electric self-potential time series associated to two 1993 earthquakes in Mexico

Flores-Márquez

Márquez-Cruz

Ramírez-Rojas³

et al. 2007

Nat. Hazards Earth Syst. Sci.

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Abstract. Recent studies related with earthquake prediction involve statistical studies of the ground electric self-potential behavior. Published results about the complexity of this kind of processes encourage us to study the statistical behavior of the ground electric self-potential recorded in Guerrero state, Mexico. This region is characterized by high seismicity. The electric self-potential variations were recorded in the Acapulco station directly from the ground. The sampling period was four seconds and the data were stored from March to December of 1993. Two significant earthquakes (EQs) occurred near this station, 15 May and 24 October whose magnitudes were Mw=6.0 and Mw=6.6 respectively. A preliminary processing was carried out consisting of a moving average of the original time series in order to filter the very high frequencies and to complete short lacks of data and outliers. Then, a visual inspection of the complete filtered signal was performed to search some seismic electric signals (SES), which were ambiguously depicted. Subsequently, a detrending of µ=0 was applied with the windows of 3.3, 6.6 and 10 h. Later, the analysis of the spectral exponent β was made, showing changes during the total period examined, and the most evident changes occurred during the preparation mechanism of the Mw=6.6 EQ. Fifteen days before the 24 October EQ, a Brownian-noise like behavior was displayed (β≈2), having a duration of about two days. In addition a Higuchi fractal method and wavelet analysis were made confirming the presence of the β-anomaly.

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Electromagnetic Signature of Prefracture Criticality in Heterogeneous Media

Cited by 87 publications

References 29 publications

Unfolding the procedure of characterizing recorded ultra low frequency, kHZ and MHz electromagnetic anomalies prior to the L'Aquila earthquake as pre-seismic ones - Part 2

Unfolding the procedure of characterizing recorded ultra low frequency, kHZ and MHz electromagnetic anomalies prior to the L'Aquila earthquake as pre-seismic ones - Part 2

Tsallis and Levy statistics in the preparation of an earthquake

A statistical analysis of electric self-potential time series associated to two 1993 earthquakes in Mexico

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