Electromagnetic emission under uniaxial compression of ice: I. Identification of nonstationary processes of structural relaxation by electromagnetic signals

2005 ◽  
Vol 50 (6) ◽  
pp. 994-1004 ◽  
Author(s):  
A. A. Shibkov ◽  
M. A. Zheltov ◽  
V. V. Skvortsov ◽  
R. Yu. Kol’tsov ◽  
A. V. Shuklinov
Keyword(s):  
Uniaxial Compression ◽  
Structural Relaxation ◽  
Electromagnetic Emission ◽  
Nonstationary Processes ◽  
Electromagnetic Signals

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 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 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.

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.

Электромагнитные методы контроля изменений напряженно-деформированного состояния диэлектрических материалов

2021 ◽  
pp. 44-53
Author(s):  
А.А. Беспалько ◽  
Д.Д. Данн ◽  
М.В. Петров ◽  
Е.К. Помишин ◽  
Г.Е. Уцын ◽  
...  
Keyword(s):  
Strain State ◽  
Experimental Studies ◽  
Electromagnetic Emission ◽  
Acoustic Excitation ◽  
Acoustic Sounding ◽  
Rock Samples ◽  
Electromagnetic Responses ◽  
Electromagnetic Signals ◽  
Complex Methods ◽  
Sample Axis

Mechanical-electrical and acoustic-electrical complex methods of testing cracking while changing the stress-strain state in dielectrics are discussed on the example of rock samples. The paper discusses the results of numerical and experimental studies of changes in the electromagnetic responses parameters under the pulse deterministic acoustic excitation of rock samples with different composition and texture. Also the results of mathematical calculations of the stress concentration on cracks located along the sample axis are presented, perpendicular to which deterministic acoustic pulses were introduced. The experimental studies results of sample electromagnetic emission with containing calcite and magnetite under uniaxial compression to fracture are shown. Regularities in the electromagnetic signals amplitudes changes during acoustic sounding in the process of «stepwise» uniaxial loading by compression to destruction are given.

scholarly journals Experimental evidence of the compatibility of the cumulative electromagnetic energy release data, with the hierarchical models for the catastrophic fracturing process

2011 ◽  
Vol 11 (6) ◽  
pp. 1605-1608 ◽  
Author(s):  
D. Mastrogiannis ◽  
V. Hadjicontis ◽  
C. Mavromatou
Keyword(s):  
Energy Release ◽  
Prediction Method ◽  
Electromagnetic Emission ◽  
Cumulative Energy ◽  
Emission Data ◽  
Electromagnetic Pulses ◽  
Fracturing Process ◽  
Release Data ◽  
Electromagnetic Signals ◽  
The Moment

Abstract. In this paper, we performed experiments of uniaxial compression of granite samples and recorded time series of electromagnetic pulses during the evolution of the catastrophic fracturing process. The cumulative energy release of the electromagnetic emission (EME) up to the critical point at the moment of rupture was then calculated. It was shown, that the validity of the proposed hierarchy models for the catastrophic fracturing process of composite materials, in analogy to critical phenomena, can be experimentally established not only via acoustic emission data, but via electromagnetic emission data as well. The above conclusion could be a useful tool for the improvement of the earthquake prediction method, based on precursory electromagnetic signals.

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

2014 ◽  
Vol 14 (6) ◽  
pp. 1383-1389 ◽  
Author(s):  
A. A. Panfilov
Keyword(s):  
Laboratory Experiments ◽  
Experimental Studies ◽  
Electromagnetic Emission ◽  
Mechanical Action ◽  
Impact Action ◽  
Rock Samples ◽  
Electric Component ◽  
Electromagnetic Emissions ◽  
Electromagnetic Signals ◽  
The Impact

Abstract. The paper presents the results of laboratory experiments on electromagnetic emissions excitation (the electric component of electromagnetic fields) 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 an increasing number of hits. It was found that strong electromagnetic signals, generated while rock samples were fracturing, were accompanied by repetitive weak but perceptible variations in the electric field intensity in short frequency ranges.

Sign in / Sign up

Export Citation Format

Share Document