Studies of electromagnetic emission of seismotectonic origin in the Kirghiz S.S.R.

Nikiforova, N. N.; Yudakhin, F. N.; Toktosopiev, A.M.

doi:10.1016/0031-9201(89)90215-x

Cited by 12 publications

(6 citation statements)

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“…It was reported by Russian and Japanese scientists that pre-earthquake electromagnetic radiation abnormal strengthening phenomena in the lower frequency ranges were observed by the ground-based sites (Nikiforova et al 1989;Morgunov and Matveev 1990;Uyeda et al 2002). Since 1991, Chinese scholars also joined this researching field and some achievements had been made (Guan and Liu 1995;Yu et al 2010;Zhang et al 2012;Zhima et al 2012).…”

Section: Slf/elf Emission As Earthquake Precursor and Field On And Nementioning

confidence: 94%

Historical and Technical Overview of SLF/ELF Electromagnetic Wave Propagation

Pan¹,

Li²

2013

Advanced Topics in Science and Technology in China

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In general, very low frequency (VLF) refers to electromagnetic waves with frequencies from 3 kHz to 30 kHz; ultra low frequency (ULF) refers to frequency range between 300 Hz to 3 kHz; the frequency range of 30 Hz to 300 Hz is defined as super low frequency (SLF); and the frequency below 30 Hz is referred to as extremely low frequency (ELF). In some early studies, alternative definitions may have been used with frequency range of 3 Hz to 3 kHz generally referred to ELF. In this book, the emphasis is on SLF (30-300 Hz) and ELF (below 30 Hz) ranges, using the MKS system of units and the time dependency e −iωt . Medium Characteristics of SLF/ELF Wave PropagationDue to the long wavelength, SLF/ELF waves, when excited and propagated on and near the Earth's surface, will cover lithosphere, atmosphere and ionosphere, whose electromagnetic characteristics differ significantly in their propagation paths. The permeability of the atmosphere and ionosphere is approximately μ 0 , the permeability in free space, as well as that of the lithosphere, except in the regions that are rich in iron, nickel, cobalt, etc. Therefore, the permeability of the lithosphere can be also treated as μ 0 , if neither the transmitter nor the receiver is located in mineral-rich areas. The atmosphere is a non-conductive medium with negligible conductivity, whose permittivity is close to ε 0 , the permittivity of free space. While the lithosphere is conductive, the conductivity of sea water σ sea is in the range of 2.5-5.5 S/m, and the conductivity σ g of rock and soil in the range of 10 −2 -10 −4 S/m. The dielectric constant ε r of the lithosphere does not have large effects on the propagation of SLF/ELF waves.The ionosphere is composed of partially ionized gas, which includes electrons, ions, and electrically neutral particles, above 70 km or so from the sea level. The electrons and ions make the ionosphere conductive, thus the majority of the energy of the incident VLF/SLF/ELF waves will be reflected by the ionosphere. When both the transmitter and the receiver are located in the space between the ground and the W. Pan, K. Li, Propagation of SLF/ELF Electromagnetic Waves,

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Section: Slf/elf Emission As Earthquake Precursor and Field On And Nementioning

confidence: 94%

Historical and Technical Overview of SLF/ELF Electromagnetic Wave Propagation

Pan¹,

Li²

2013

Advanced Topics in Science and Technology in China

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“…The first EMR anomaly was registered two weeks before, and another powerful EMR emission (20 dB higher than the usual noise level) was observed one day prior to the eruption. Nikiforova and Yadakhin (1989) investigated EMR in the Issik-Kul, Kyrgyzstan seismic region at a frequency of 15 kHz. They obtained a significant increase of EMR intensity in the immediate zone of active geological faults, and claimed that the EMR sources were of ionosphere origin.…”

Section: Emr From Rocks In Connection With Earthquake Prognosismentioning

confidence: 99%

Experimental and theoretical investigations of electromagnetic radiation induced by rock fracture

Bahat

Goldbaum²,

Frid

et al. 2000

Israel Journal of Earth Sciences

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There is a general agreement in the literature that the technique of measuring electromagnetic radiation (EMR) emitted from cracked rock is a good candidate for forecasting of earthquakes. Our immediate objective in pursuing this goal is to correlate EMR with crack dimensions in micro-scales (mm-cm), coupling it with the understanding of atomic-scale phenomena for coherently understanding the EMR process. We review some of the results obtained in this laboratory. They include the isolation, both experimentally and theoretically, of an individual EMR pulse. Individual EMR pulse parameters are correlated with crack dimensions: the time from pulse origin up to its maximum is proportional to the crack length, and the frequency of the EMR pulse relates to the crack width. Individual EMR pulses are classified both according to their length and according to their location on the stress-strain curve. We find that the key elastic parameter for EMR characterization during triaxial compression is the Poisson ratio: the lower the Poisson ratio, the higher the EMR activity. Amplitudes of EMR and their changes with loading are shown to be independent of crack mode (tensile vs. shear), they are only dependent on the entire crack area. In order to experimentally overcome load limitations we introduce a new sample shape, the truncated cone, that fails more readily than standard cylindrical samples.

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“…However, in the previous research, a unified physical model for an Earth-airionosphere region was not employed to treat quantitatively the electromagnetic field radiated by underground radiation source. Meanwhile, the case for the observation point being located on the Earth's surface was investigated widely, and the case for the observation point located in the ionosphere was seldom considered (Nikiforova et al 1989;Morgunov and Matveev 1990;Uyeda et al 2002).…”

Section: Introductionmentioning

confidence: 99%

SLF/ELF Field in Air and Ionosphere Generated by Earthquake Radiation Source

Pan¹,

2013

Advanced Topics in Science and Technology in China

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In this chapter, we treat analytically SLF/ELF field in air and ionosphere radiated by an HED in the Earth. The region of interest consists of the lithosphere, air, and ionosphere. For the planar model, the analytical solution for SLF/ELF field in the air and ionosphere generated by an underground HED is obtained readily. Then, comparison and analyses are treated for both planar and spherical models. Finally, computations are carried out and discussions are presented.

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Studies of electromagnetic emission of seismotectonic origin in the Kirghiz S.S.R.

Cited by 12 publications

References 0 publications

Historical and Technical Overview of SLF/ELF Electromagnetic Wave Propagation

Historical and Technical Overview of SLF/ELF Electromagnetic Wave Propagation

Experimental and theoretical investigations of electromagnetic radiation induced by rock fracture

SLF/ELF Field in Air and Ionosphere Generated by Earthquake Radiation Source

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