Monitoring ULF magnetic disturbances and schemes for recognizing earthquake precursors

Hayakawa, Masashi; Kopytenko, Yu. A.; Смирнова, Н. А.; Troyan, V.N.; Peterson, Th.

doi:10.1016/s1464-1895(00)00042-9

Cited by 19 publications

(10 citation statements)

References 8 publications

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“…2002; Smirnova et al, 2001;Hayakawa et al, 2000b;Gotoh et al, 2003). This study reinforces our hypothesis that the behaviour of parameter β (or H ) seems to be a candidate precursor of failure.…”

Section: Indications Of a Universal Behavioursupporting

confidence: 87%

Evolving towards a critical point: A possible electromagnetic way in which the critical regime is reached as the rupture approaches

Kapiris

Eftaxias

Νομικός

et al. 2003

Nonlin. Processes Geophys.

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Abstract. In analogy to the study of critical phase transitions in statistical physics, it has been argued recently that the fracture of heterogeneous materials could be viewed as a critical phenomenon, either at laboratory or at geophysical scales. If the picture of the development of the fracture is correct one may guess that the precursors may reveal the critical approach of the main-shock. When a heterogeneous material is stretched, its evolution towards breaking is characterized by the appearance of microcracks before the final break-up. Microcracks produce both acoustic and electromagnetic (EM) emission in the frequency range from VLF to VHF. The microcracks and the associated acoustic and EM activities constitute the so-called precursors of general fracture. These precursors are detectable not only at laboratory but also at geophysical scales. VLF and VHF acoustic and EM emissions have been reported resulting from volcanic and seismic activities in various geologically distinct regions of the world. In the present work we attempt to establish the hypothesis that the evolution of the Earth's crust towards the critical point takes place not only in a mechanical but also in an electromagnetic sense. In other words, we focus on the possible electromagnetic criticality, which is reached while the catastrophic rupture in the Earth's crust approaches. Our main tool is the monitoring of micro-fractures that occur before the final breakup, by recording their radioelectromagnetic emissions. We show that the spectral power law analysis of the electromagnetic precursors reveals distinguishing signatures of underlying critical dynamics, such as: (i) the emergence of memory effects; (ii) the decrease with time of the anti-persistence behaviour; (iii) the presence of persistence properties in the tail of the sequence of the precursors; and (iv) the acceleration of the precursory electromagnetic energy release. Moreover, the statistical analysis of the amplitudes of the electromagnetic fluctuations reveals the breaking of the symmetry as the theory predicts. Finally, we try to answer the question: how universal the observed Correspondence to: K. A. Eftaxias (ceftax@phys.uoa.gr) electromagnetic critical behaviour of the failing system is?

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Section: Indications Of a Universal Behavioursupporting

confidence: 87%

Evolving towards a critical point: A possible electromagnetic way in which the critical regime is reached as the rupture approaches

Kapiris

Eftaxias

Νομικός

et al. 2003

Nonlin. Processes Geophys.

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“…This frequency range is also favourable for detection of electromagnetic signals of lithospheric origin, which could be related to the earthquake preparation processes. The corresponding consideration based on the field observations and also on the estimations of the appropriate skin depths for electromagnetic waves is contained in Kopytenko et al (1993aKopytenko et al ( , b, 1994Kopytenko et al ( , 2001, Hayakawa et al (1996Hayakawa et al ( , 1999Hayakawa et al ( , 2000b, and . The calculations of skin depth values show the ability of the ULF electromagnetic fields of space origin to penetrate the earthquake focal areas.…”

Section: Experimental Data and The Analysis Methodologymentioning

confidence: 99%

Scaling characteristics of ULF geomagnetic fields at the Guam seismoactive area and their dynamics in relation to the earthquake

Смирнова

Hayakawa

Gotoh

et al. 2001

Nat. Hazards Earth Syst. Sci.

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Abstract. The long-term evolution of scaling (fractal) characteristics of the ULF geomagnetic fields in the seismoactive region of the Guam Island is studied in relation to the strong (Ms = 8.0) nearby earthquake of 8 August 1993. The selected period covers 10 months before and 10 months after the earthquake. The FFT procedure, Burlaga-Klein approach and Higuchi method, have been applied to calculate the scaling exponents and fractal dimensions of the ULF time series. It is found that the spectrum of ULF emissions exhibits, on average, a power law behaviour S(f ) ∝ f −β , which is a fingerprint of the typical fractal (self-affine) time series. The spectrum slope β fluctuates quasi-periodically during the course of time in a range of β = 2.5−0.7, which corresponds to the fractional Brownian motion with both persistent and antipersistent behaviour. An tendency is also found for the spectrum slope to decrease gradually when approaching the earthquake date. Such a tendency manifests itself at all local times, showing a gradual evolution of the structure of the ULF noise to a typical flicker noise structure in proximity to the large earthquake event. We suggest considering such a peculiarity as an earthquake precursory signature. One more effect related to the earthquake is revealed: the longest quasiperiod, which is 27 days, disappeared from the variations of the ULF emission spectrum slope during the earthquake, and it reappeared three months after the event. Physical interpretation of the peculiarities revealed has been done on the basis of the SOC (self-organized criticality) concept.

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“…The north-south component data for the whole period (1 year) of tripartite observation were used to differentiate the variations caused by different sources (geomagnetic variations, man-made noise, and other sources). The ULF waveform data sampled at 1 s were fed to into a numerical 0.01 Ϯ 0.002 Hz bandpass filter on the basis of previous studies (9)(10)(11). By measuring the correlations between the data from the three stations, we estimated three eigen vectors and eigen values ( 1 Ͼ 2 Ͼ 3 ), thereby separating three components with possibly different sources.…”

Section: Magnetic Field Changesmentioning

confidence: 99%

Electric and magnetic phenomena observed before the volcano-seismic activity in 2000 in the Izu Island Region, Japan

Uyeda

Hayakawa

Nagao

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

182

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Significant anomalous changes in the ultra low frequency range (Ϸ0.01 Hz) were observed in both geoelectric and geomagnetic fields before the major volcano-seismic activity in the Izu Island region, Japan. The spectral intensity of the geoelectric potential difference between some electrodes on Niijima Island and the third principal component of geomagnetic field variations at an array network in Izu Peninsula started to increase from a few months before the onset of the volcano-seismic activity, culminating immediately before nearby magnitude 6 class earthquakes. Appearance of similar changes in two different measurements conducted at two far apart sites seems to provide information supporting the reality of preseismic electromagnetic signals.

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Monitoring ULF magnetic disturbances and schemes for recognizing earthquake precursors

Cited by 19 publications

References 8 publications

Evolving towards a critical point: A possible electromagnetic way in which the critical regime is reached as the rupture approaches

Evolving towards a critical point: A possible electromagnetic way in which the critical regime is reached as the rupture approaches

Scaling characteristics of ULF geomagnetic fields at the Guam seismoactive area and their dynamics in relation to the earthquake

Electric and magnetic phenomena observed before the volcano-seismic activity in 2000 in the Izu Island Region, Japan

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