Directionality of surface high-frequency geoacoustic emission during deformational disturbances

2010 ◽  
Vol 430 (1) ◽  
pp. 67-70 ◽  
Author(s):  
B. M. Shevtsov ◽  
Yu. V. Marapulets ◽  
A. O. Shcherbina
Keyword(s):  
High Frequency ◽  
Geoacoustic Emission

Relationship of high-frequency geoacoustic emission and electric field in the atmosphere in seismotectonic process

2010 ◽  
Vol 431 (1) ◽  
pp. 361-364 ◽  
Author(s):  
Yu. V. Marapulets ◽  
O. P. Rulenko ◽  
M. A. Mishchenko ◽  
B. M. Shevtsov
Keyword(s):  
Electric Field ◽  
High Frequency ◽  
Geoacoustic Emission ◽  
Relationship Of

scholarly journals Adaptive Threshold Scheme for Pulse Detection under Condition of Background Nonstationary Noise

2021 ◽  
Vol 2096 (1) ◽  
pp. 012019
Author(s):  
A O Shcherbina ◽  
O O Lukovenkova ◽  
A A Solodchuk
Keyword(s):  
High Frequency ◽  
Background Noise ◽  
Signal Amplitude ◽  
Threshold Value ◽  
Adaptive Threshold ◽  
Threshold Scheme ◽  
Pulse Detection ◽  
Geoacoustic Emission ◽  
Time Parameters ◽  
Frequency Pulse

Abstract The paper describes a new adaptive threshold scheme for detecting pulses in high-frequency signals against a background of non-stationary noise. The result of the scheme operation is to determine the pulse boundaries by comparing the signal amplitude-time parameters with the threshold. The threshold value is calculated in non-overlapping windows of fixed length and depends only on the background noise level. The detected pulses undergo additional shape checking, taking into account their characteristics. The parameters of the algorithms for detecting pulses and checking their shape can be adjusted for any type of high-frequency pulse signals. This threshold scheme is tuned to detect pulses in high frequency geoacoustic emission signals. The results of the scheme operation on an artificial signal and on fragments of a geoacoustic signal are given, a comparison is made between the proposed scheme and the previously used (outdated) one. The new threshold scheme proposed by the authors is less sensitive to the choice of the initial threshold value and it is more stable in operation. When processing 15-minute fragments of a geoacoustic signal, the new scheme correctly detects, on average, 5 times more pulses.

Anomaly in high-frequency geoacoustic emission as a close earthquake precursor

2008 ◽  
Vol 54 (1) ◽  
pp. 82-93 ◽  
Author(s):  
V. A. Gordienko ◽  
T. V. Gordienko ◽  
N. V. Krasnopistsev ◽  
A. V. Kuptsov ◽  
I. A. Larionov ◽  
...  
Keyword(s):  
High Frequency ◽  
Earthquake Precursor ◽  
Geoacoustic Emission

scholarly journals Joint Anomalies of High-Frequency Geoacoustic Emission and Atmospheric Electric Field by the Ground–Atmosphere Boundary in a Seismically Active Region (Kamchatka)

Atmosphere ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 267 ◽  
Author(s):  
Yury Marapulets ◽  
Oleg Rulenko
Keyword(s):  
Electric Field ◽  
High Frequency ◽  
Weather Conditions ◽  
Atmospheric Electric Field ◽  
Near Surface ◽  
Geoacoustic Emission ◽  
Sign Change ◽  
The Common ◽  
Calm Weather ◽  
Short Time

The authors generalize and analyze the investigation results of joint anomalies of high-frequency geoacoustic emission and atmospheric electric field by the ground–atmosphere boundary which were detected by them in Kamchatka. These anomalies are observed as geoacoustic emission increases in kilohertz frequency range and bay-like decreases of atmospheric electric field with the sign change which occur close in time during calm weather conditions. It is the authors’ opinion that the common nature of these anomalies is short-time stretching of the near-surface sedimentary rocks at an observation site during unstable tectono-seismic process. A scheme of the detected anomalies formation has been suggested.

scholarly journals Coupling mechanism between geoacoustic emission and electromagnetic anomalies prior to earthquakes

2014 ◽  
Vol 3 (1) ◽  
Author(s):  
Viacheslav Pilipenko ◽  
Evgeniy Fedorov
Keyword(s):  
Fluid Dynamics ◽  
Acoustic Emission ◽  
High Frequency ◽  
Effective Viscosity ◽  
Laboratory Experiments ◽  
Coupling Mechanism ◽  
Filtration Process ◽  
Geoacoustic Emission ◽  
Low Intensity ◽  
Acoustic Impact

Micro-cracking in the earthquake preparation zone is accompanied by the generation of acoustic emission (AE). Even low-intensity AE can essentially modify the underground fluid dynamics owing to the influence of high-frequency acoustic field on filtration process. Laboratory experiments show that acoustic impact on pour sample destroys a film with bounded water and results in a steep increase of its permeability up to 2 orders of magnitude. Impulsive acoustic fields also decrease the effective viscosity of the fluid. The occurrence in the crust under pressure of a region with distinct hydrodynamic and electrokinetic parameters will result in an appearance of anomalous telluric and magnetic fields on the surface above. This effect is estimated analytically using a simple model with an ellipticshaped inhomogeneity. The suggested hypothesis about possible coupling between AE and geoelectrical anomalies needs observational verification.

The Microstructure of Steatite (Protoenstatite)

1985 ◽  
Vol 43 ◽  
pp. 236-237
Author(s):  
W. E. Lee ◽  
A. H. Heuer
Keyword(s):  
High Frequency ◽  
Glass Ceramics ◽  
Magnesium Silicate ◽  
Beam Current ◽  
Glassy Matrix ◽  
Angle Of Incidence ◽  
X Ray ◽  
Mechanical And Electrical Properties ◽  
Argon Ions ◽  
High Temperature Polymorph

IntroductionTraditional steatite ceramics, made by firing (vitrifying) hydrous magnesium silicate, have long been used as insulators for high frequency applications due to their excellent mechanical and electrical properties. Early x-ray and optical analysis of steatites showed that they were composed largely of protoenstatite (MgSiO3) in a glassy matrix. Recent studies of enstatite-containing glass ceramics have revived interest in the polymorphism of enstatite. Three polymorphs exist, two with orthorhombic and one with monoclinic symmetry (ortho, proto and clino enstatite, respectively). Steatite ceramics are of particular interest a they contain the normally unstable high-temperature polymorph, protoenstatite.Experimental3mm diameter discs cut from steatite rods (∼10” long and 0.5” dia.) were ground, polished, dimpled, and ion-thinned to electron transparency using 6KV Argon ions at a beam current of 1 x 10-3 A and a 12° angle of incidence. The discs were coated with carbon prior to TEM examination to minimize charging effects.

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