scholarly journals Acoustic–electromagnetic effects of tectonic movements of the crust – borehole survey

2015 ◽  
Vol 7 (2) ◽  
pp. 1447-1468
Author(s):  
V. N. Uvarov ◽  
E. I. Malkin ◽  
G. I. Druzhin ◽  
D. V. Sannikov ◽  
V. M. Pukhov
Keyword(s):  
Stress Relaxation ◽  
Electromagnetic Radiation ◽  
Rock Fracture ◽  
Electromagnetic Emission ◽  
Tectonic Stress ◽  
Signal Frequency ◽  
Deep Layers ◽  
Shear Relaxation ◽  
Electromagnetic Signals ◽  
Hydrocarbon Deposits

Abstract. Borehole radiophysical properties are briefly described. Borehole investigation of lithosphere acoustic-electromagnetic radiation was carried out in a seismically active region. Four main types of anomalies of acoustic-electromagnetic radiation were distinguished. They correspond to shear and bulk relaxations of tectonic stress. Stability of phase relations of acoustic and electromagnetic signals in the region of anomalies was detected that allows us to state their coherence. It was concluded that the reason of mutual coherence of acoustic and electromagnetic signals is the magnetoelastic effect of the casing pipe. A mechanism of generation of rock self-induced vibrations during tectonic stress relaxation causing acoustic-electromagnetic emission was suggested. It was concluded that "sigmoid" anomalies may correlate with excitation of eigen vibrations in a fracture cavity during brittle shear relaxation of rock tectonic stress. An explanation of the change of anomalous "sigmoid" signal frequency was given. It is considered to be the result of growth of rock fracture cavity and the decrease of tectonic stress relaxation. It was concluded that a borehole, cased in a steel pipe, together with a system of inductance coils and a hydrophone is the effective sounding sensor for acoustic fields of interior deep layers. It may be applied to investigate and to monitor the geodynamic activity, in particular, in earthquake forecasts and in monitoring of hydrocarbon deposits during their production.

ONSET TIME DETERMINATION OF ACOUSTIC AND ELECTROMAGNETIC EMISSION DURING ROCK FRACTURE

2012 ◽  
Vol 35 ◽  
pp. 51-62 ◽  
Author(s):  
Gianni Niccolini ◽  
Jie Xu ◽  
Amedeo Manuello ◽  
Giuseppe Lacidogna ◽  
Alberto Carpinteri
Keyword(s):  
Rock Fracture ◽  
Onset Time ◽  
Electromagnetic Emission ◽  
Time Determination

Relationship Between Frequency of Electromagnetic Radiation Induced by Rock Fracture and Elastic Parameters

2006 ◽  
Vol 49 (5) ◽  
pp. 1368-1374 ◽  
Author(s):  
Qiang GONG ◽  
Xiang-Yun HU ◽  
Sheng-Ye ZHANG ◽  
Rong ZHANG ◽  
Xiao-Zhu HAO
Keyword(s):  
Electromagnetic Radiation ◽  
Rock Fracture ◽  
Elastic Parameters ◽  
Radiation Induced

A three-axis antenna to measure near-field low-frequency electromagnetic radiation generated from rock fracture

Measurement ◽  
2020 ◽  
pp. 108563
Author(s):  
Menghan Wei ◽  
Dazhao Song ◽  
Xueqiu He ◽  
Majid Khan ◽  
Zhenlei Li ◽  
...  
Keyword(s):  
Electromagnetic Radiation ◽  
Rock Fracture ◽  
Near Field ◽  
Low Frequency

scholarly journals The results of experimental studies of VLF–ULF electromagnetic emission by rock samples due to mechanical action

2013 ◽  
Vol 1 (6) ◽  
pp. 7821-7842
Author(s):  
A. A. Panfilov
Keyword(s):  
Laboratory Experiments ◽  
Experimental Studies ◽  
Electromagnetic Emission ◽  
Mechanical Action ◽  
Frequency Range ◽  
Impact Action ◽  
Rock Samples ◽  
Electric Component ◽  
Electromagnetic Signals ◽  
The Impact

Abstract. The paper presents the results of laboratory experiments on electromagnetic emission excitation (electric component of electromagnetic field) by rock samples due to different forms of mechanical stress applications. It was shown that samples generate electric impulses with different spectra when the impact action, gradual loading or dynamic friction is applied. It was ascertained that level and spectral compositions of signals, generated by rock samples, change with increasing quantity of hits. It was found that strong electromagnetic signals, generated while rock samples were fracturing, were accompanied by repetitive weak, but perceptible variations of the electric field intensity in short frequency range.

scholarly journals Comparative analysis of acoustic and electromagnetic emissions of rocks

2021 ◽  
Vol 929 (1) ◽  
pp. 012013
Author(s):  
V N Klyuchkin ◽  
V A Novikov ◽  
V I Okunev ◽  
V A Zeigarnik
Keyword(s):  
Comparative Analysis ◽  
Uniaxial Compression ◽  
High Stress ◽  
Electromagnetic Emission ◽  
Rock Failure ◽  
Dynamic Rupture ◽  
Block Model ◽  
Rock Samples ◽  
Electromagnetic Emissions ◽  
Electromagnetic Signals

Abstract Comparative analysis of acoustic and electromagnetic emissions recorded during the intact rock samples deformation and dynamic rupture of simulated crustal fault is presented. Specialized machines for uniaxial compression and shear tests of rock samples with identical data acquisition systems for both test cases were employed. Increase of acoustic emission was observed accompanied by significant rise of intensity and amplitude of electromagnetic signals at high stress of the rock samples under the uniaxial compression or dynamic failure in the spring-block model. Such correlation is consistent with the previous conclusions that an increase of electromagnetic emission may be considered as a rock failure precursor. Any specific characteristics of the detected electromagnetic signals to be used for prediction of impending rock failure or the earthquake fault rupture were not found. The similarity of electromagnetic signals and their spectra obtained at the press equipment and the spring-block model suggests that in both cases, the signals observed are generated by the crack formations and shear. The electromagnetic emission appeared only in dry samples. The samples saturated by water with the salinity of over 0.1% demonstrated no electromagnetic emission.

scholarly journals Numerical Calculation of Electric Fields in Housing Spaces Due to Electromagnetic Radiation from Antennas for Mobile Communication

10.14311/478 ◽  
2003 ◽  
Vol 43 (5) ◽  
Author(s):  
H.-P. Geromiller ◽  
A. Farschtschi
Keyword(s):  
Electromagnetic Wave ◽  
Electric Field ◽  
Electromagnetic Radiation ◽  
Electric Fields ◽  
Mobile Communication ◽  
Signal Frequency ◽  
High Signal ◽  
Maximum Value ◽  
Mobile Antennas ◽  
The Impact

The influence of electromagnetic radiation from mobile antennas on humans is under discussion in va'rious groups ofscientists, This paper deals with the impact ofelectromagnetic radiation in a housing space. The space is assumedto be bordered by 5 walls of ferroconcrete and a door-window combination on the 6th side, the latter to be electromagnetically transparent. The transparent side of the housing is exposed to an electromagnetic wave. As the source ofradiation is considered to be far away from the housing, the radiation is regarded to be from a plane wave. Due to the high signal frequency and ferroconcrete walls, 5 sides ofthe housing space are considered to be perfect conductors. The electric field inside the housing is calculated numerically by the method of finite differences for different angles of incidence of the radiated electromagnetic wave. The maximum value of the calculated electric field is outlined in a diagram.

scholarly journals Stress induced polarization currents and electromagnetic emission from rocks and ionic crystals, accompanying their deformation

2004 ◽  
Vol 4 (5/6) ◽  
pp. 633-639 ◽  
Author(s):  
V. Hadjicontis ◽  
C. Mavromatou ◽  
D. Ninos
Keyword(s):  
Piezoelectric Materials ◽  
Electromagnetic Emission ◽  
Induced Polarization ◽  
Ionic Crystals ◽  
Uniaxial Deformation ◽  
Plausible Model ◽  
Plausible Answer ◽  
Preparatory Stage ◽  
Electromagnetic Signals ◽  
Electric Signals

Abstract. A crucial question of the scientific community nowadays, concerns the existence of electric signals preceding earthquakes. In order to give a plausible answer to this question, we carried out two kinds of laboratory experiments of uniaxial deformation of ionic crystals and rock samples: a) In the first kind, stress induced polarization currents are detected and recorded. Our experimental results showed not only the existence of stress induced polarization currents before the fracture of the samples, but the possibility of the propagation of these signals, as well, through conductive channels, for distances much longer than the source dimensions. b) In the second, acoustic and electromagnetic signals are detected and recorded in the frequency range from 1KHz to some MHz. The mechanism of generation of these signals is shown to be different for those emitted from piezoelectric and from non-piezoelectric materials. A plausible model is also suggested, on the compatibility of our laboratory results with the processes occurring in the earth during the earthquake preparatory stage.

Experimental and theoretical investigations of electromagnetic radiation induced by rock fracture

2000 ◽  
Vol 49 (1) ◽  
pp. 9-19 ◽  
Author(s):  
Dov Bahat ◽  
Julia Goldbaum ◽  
Vladimir Frid ◽  
Avinoam Rabinovitch ◽  
Vladimir Frid ◽  
...  
Keyword(s):  
Electromagnetic Radiation ◽  
Rock Fracture ◽  
Theoretical Investigations ◽  
Radiation Induced

Research progress on electromagnetic radiation in gas-containing coal and rock fracture and its applications

2012 ◽  
Vol 50 (4) ◽  
pp. 728-735 ◽  
Author(s):  
Xueqiu He ◽  
Baisheng Nie ◽  
Wenxue Chen ◽  
Enyuan Wang ◽  
Linming Dou ◽  
...  
Keyword(s):  
Electromagnetic Radiation ◽  
Rock Fracture ◽  
Research Progress

The Development of Rock Failure Electromagnetic Emission Monitoring System

2013 ◽  
Vol 330 ◽  
pp. 401-406
Author(s):  
Song Ling Huang ◽  
Fu Rong Zhu ◽  
Hong Xiu Zhu ◽  
Zheng Wei ◽  
Shen Wang
Keyword(s):  
Data Acquisition ◽  
Monitoring System ◽  
Electromagnetic Induction ◽  
Rock Fracture ◽  
Electromagnetic Emission ◽  
Rock Failure ◽  
Mine Safety ◽  
Signal Conditioning ◽  
Signal Conditioning Circuit ◽  
Conditioning Circuit

The research about electromagnetic emission (EME) during rock failure is very important to earthquake prediction and mine safety. A corresponding monitoring system has been developed according to the characteristics of EME signals during rock fracture, which include a wide frequency band and small amplitude of the inductive signals. The system is constituted by electromagnetic induction probe, signal-conditioning circuit and a computer for data acquisition. Among them, the electromagnetic induction probe can detect spatial magnetic field changes in a certain direction and convert it into electrical signals, the signal-conditioning circuit can magnify, filter and isolate signals acquired by the probe, and the computer for data acquisition is used for recording and displaying the detected signals. Several testing results have been achieved in rock failure experiments on marble that are carried out both by mechanical loading and expansion caused by chemical agents.

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