scholarly journals Electrical and magnetic data time series’ observations as an approach to identify the seismic activity of non-anthropic origin

2021 ◽  
Vol 25 (3) ◽  
pp. 297-307
Author(s):  
Juan Manuel Solano Fino ◽  
Alexander Caneva ◽  
Carlos Alberto Vargas Jiménez ◽  
Luis Hernán Ochoa
Keyword(s):  
Electrical Potential ◽  
Magnetic Data ◽  
Seismic Events ◽  
National University ◽  
Seismic Records ◽  
Electromagnetic Signals ◽  
Electric Signals ◽  
Electromagnetic Precursors ◽  
Magnetic Disturbances ◽  
Seismological Network

In this work, the authors tried to identify a possible relationship between electromagnetic signals (EM) and seismic events in the lithospheric system in the central region of Colombia. The data, both seismic records and electromagnetic signals, were taken from the catalog of the Seismological Network of the National University of Colombia (RSUNAL) and the catalog of the National Seismological Network of Colombia (RSNC). The project included the design and instrument testing phases for recording seismic signals, electrical potential variations, and magnetic field variations to try to identify possible relationships between these signals. Possible electromagnetic precursors for seismic events were observed, mainly magnetic disturbances, but it was not possible to locate evident electrical anomalies (Seismic Electric Signals - SES). Thus, although the results are not conclusive, the magnetic disturbances identified deserve further long-term analysis.

Surface wave attenuation of seismic records with the co-core trace transform filter

Geophysics ◽  
2011 ◽  
Vol 76 (6) ◽  
pp. V115-V128 ◽  
Author(s):  
Ning Wu ◽  
Yue Li ◽  
Baojun Yang
Keyword(s):  
Surface Wave ◽  
Surface Waves ◽  
Field Data ◽  
Wave Attenuation ◽  
Seismic Events ◽  
Data Sets ◽  
Transform Domain ◽  
Recent Developments ◽  
Seismic Records ◽  
Trace Transform

To remove surface waves from seismic records while preserving other seismic events of interest, we introduced a transform and a filter based on recent developments in image processing. The transform can be seen as a weighted Radon transform, in particular along linear trajectories. The weights in the transform are data dependent and designed to introduce large amplitude differences between surface waves and other events such that surface waves could be separated by a simple amplitude threshold. This is a key property of the filter and distinguishes this approach from others, such as conventional ones that use information on moveout ranges to apply a mask in the transform domain. Initial experiments with synthetic records and field data have demonstrated that, with the appropriate parameters, the proposed trace transform filter performs better both in terms of surface wave attenuation and reflected signal preservation than the conventional methods. Further experiments on larger data sets are needed to fully assess the method.

scholarly journals Strength constraints of shallow crustal strata from analyses of mining induced seismicity

2013 ◽  
Vol 5 (1) ◽  
pp. 737-765 ◽  
Author(s):  
M. Alber ◽  
R. Fritschen ◽  
M. Bischoff
Keyword(s):  
Rock Mass ◽  
Strength Properties ◽  
Coal Measure ◽  
Seismic Events ◽  
Mining Induced Seismicity ◽  
Strength Tests ◽  
Seismic Records ◽  
Coal Measure Rocks ◽  
Rock Mass Failure ◽  
Strength Constraints

Abstract. Stress redistributions around large underground excavations such as coal mines may lead to failure of the surrounding rock mass. Some of these failure processes were recorded as seismic events. In this paper the different failure processes such as rock mass failure or the reactivation of faults are delineated from the seismic records. These are substantiated by rock mechanical analyses including laboratory strength tests on coal measure rocks obtained from underground drilling. Additionally, shear tests on discontinuities in coal measure rocks (slickensides in shale and rough sandstone joints) were conducted to grasp the possible variation of strength properties of faults. Numerical modeling was employed to evaluate the state of stress at the locations where seismic events did occur.

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.

Remote monitoring of electromagnetic signals and seismic events using smart mobile devices

2009 ◽  
Vol 35 (6) ◽  
pp. 1296-1303 ◽  
Author(s):  
Pantelis Georgiadis ◽  
Dionisis Cavouras ◽  
Konstantinos Sidiropoulos ◽  
Konstantinos Ninos ◽  
Constantine Nomicos
Keyword(s):  
Mobile Devices ◽  
Remote Monitoring ◽  
Seismic Events ◽  
Electromagnetic Signals ◽  
Smart Mobile ◽  
Smart Mobile Devices

scholarly journals Comment on "Non-inductive components of electromagnetic signals associated with L'Aquila earthquake sequences estimated by means of inter-station impulse response functions" by Di Lorenzo et al. (2011)

2013 ◽  
Vol 1 (1) ◽  
pp. 193-206
Author(s):  
F. Masci ◽  
G. De Luca
Keyword(s):  
Impulse Response ◽  
Seismic Event ◽  
Impulse Response Functions ◽  
L’Aquila Earthquake ◽  
Response Functions ◽  
Frequency Range ◽  
2009 L’Aquila Earthquake ◽  
Electromagnetic Signals ◽  
Earthquake Sequences ◽  
Magnetic Disturbances

Abstract. Di Lorenzo et al. (2011) document the observation of magnetic signals in the frequency range [0.3–3] Hz from few minutes before to about one hour after the 6 April 2009 L'Aquila earthquake. This coincidence induced the authors to think that the observed magnetic disturbances were related to the main phase of the seismic event. Here, we will discuss some unclear points of Di Lorenzo et al. (2011) which cast serious doubts on the seismogenic origin of the magnetic disturbances observed by the authors.

scholarly journals Co-Seismic Magnetic Field Perturbations Detected by Swarm Three-Satellite Constellation

2020 ◽  
Vol 12 (7) ◽  
pp. 1166
Author(s):  
Dedalo Marchetti ◽  
Angelo De Santis ◽  
Shuanggen Jin ◽  
Saioa A. Campuzano ◽  
Gianfranco Cianchini ◽  
...  
Keyword(s):  
Electromagnetic Scattering ◽  
Magnetic Data ◽  
Seismic Events ◽  
Ionospheric Layer ◽  
Swarm Satellites ◽  
Measured Distance ◽  
Systematic Inspection ◽  
Swarm Satellite ◽  
Large Earthquakes ◽  
Good Agreement

The first 5.3 years of magnetic data from three Swarm satellites have been systematically analyzed, and possible co-seismic magnetic disturbances in the ionosphere were investigated just a few minutes after the occurrence of large earthquakes. We preferred to limit the investigation to a subset of earthquakes selected in function of depth and magnitude. After a systematic inspection of the available data around (in time and space) the seismic events, we found 12 Swarm satellite tracks with co-seismic disturbances possibly produced by ten earthquakes from Mw5.6 to Mw6.9. The distance of the satellite to the earthquake epicenter corresponds to the measured distance-time arrival of the disturbance from the surface to the ionosphere, confirming that the identified disturbances are most likely produced by the seismic events. Secondly, we found a good agreement with a model that combined a propagation of the disturbance to the F2 ionospheric layer with an acoustic gravity wave at a velocity of about (2.2 ± 0.3) km/s and a second faster phenomenon that transmits the disturbance from F2 layer to the Swarm satellite with a velocity of about (16 ± 3) km/s as an electromagnetic scattering propagation.

Deep seismic reflection data interpretation using balanced filtering method

Geophysics ◽  
2017 ◽  
Vol 82 (5) ◽  
pp. N43-N49 ◽  
Author(s):  
Jin Zhang ◽  
Yanguo Wang ◽  
David C. Nobes ◽  
Guangnan Huang ◽  
Hongxing Li
Keyword(s):  
Seismic Reflection ◽  
Synthetic Data ◽  
Data Interpretation ◽  
Seismic Events ◽  
Seismic Reflection Data ◽  
Deep Seismic Reflection ◽  
Filtering Method ◽  
Reflection Data ◽  
Text Filtering ◽  
Seismic Records

Inverse [Formula: see text] filtering can perform energy compensation and phase correction of seismic reflection data, but it has an instability problem due to its high-pass characteristics. Although improved methods, such as gain-limited inverse [Formula: see text] filtering and stabilized inverse [Formula: see text] filtering, overcome the instability to some extent, they are not suitable for compensating deep seismic reflection events with weak energy. Focusing on the enhancement of deep seismic events, we have developed a balanced filtering method based on the ratio of the phase-compensated signal to its analytic signal counterpart. The method is insensitive to the depth of seismic records, and it can make shallow and deep seismic records visible simultaneously. When tested on synthetic data and real seismic data, compared with other methods, the balanced filtering method improves the amplitude strength of the deep reflection events and the continuity of shallow and deep seismic events effectively, which makes the deep reflection data easier to interpret.

scholarly journals Results of seismological observations on the territory of the Republic of North Ossetia-Alania and adjacent areas in 2020

2021 ◽  
Vol 3 (2) ◽  
pp. 86-95
Author(s):  
Anna Sayapina ◽  
Sofya Bagaeva ◽  
Isolda Dmitrieva ◽  
Sergey Gorozhantsev
Keyword(s):  
Seismic Energy ◽  
Seismic Events ◽  
North Caucasus ◽  
Seismic Regime ◽  
Caucasus Region ◽  
The North ◽  
The Republic ◽  
Academy Of Sciences ◽  
North Ossetia ◽  
Seismological Network

North-Ossetian Division of the Geophysical Survey of the Russian Academy of Sciences (NOD GS RAS) carries out the continuous seismological observations of the central part of the North Caucasus region. The branch's seismological network includes 12 observation points located on the territory of the Republic of North Ossetia-Alania. The paper provides basic information about the places of installation of seismic stations and their equipment, and notes the registration possibilities of the network. The total number of registered seismic events and separately within the administrative territories in 2020 is given. The total released seismic energy is calculated. A comparison of the energy indicator with the previous year is given. The schedule of repeatability is calculated and constructed, which indicates the level of reliability of event registration. The analysis of the earthquakes foci distribution with ref-erence to geotectonic structures is presented on the map of the epicenters of recorded seismic events with an indication of the distribution against the background of the focal zones. Iden-tified and described the swarm sequences of seismic events, which occurred in the territories of the Republics of North Ossetia-Alania and Kabardino-Balkaria, as well as in the Stavropol Territory. The mechanisms of the foci for the three most powerful earthquakes are deter-mined and their stereograms are given. The obtained results will allow us to study the chang-es in the seismic regime of the North Caucasus region more effectively.

scholarly journals Artificial and natural electromagnetic signals revealed during two years in the Amare cave (Central Italy)

1994 ◽  
Vol 37 (5 Sup.) ◽  
Author(s):  
F. Bella ◽  
R. Bella ◽  
P. F. Biagi ◽  
M. Caputo ◽  
G. Della Monica ◽  
...  
Keyword(s):  
Solid State ◽  
Electromagnetic Fields ◽  
Natural Frequencies ◽  
Central Italy ◽  
Southern Slope ◽  
Qualitative Explanation ◽  
Weather Events ◽  
Electromagnetic Signals ◽  
Set Up ◽  
Electric Signals

n 1990, some instrumentation was set up in the Amare cave (southern slope of the Gran Sasso chain, L'Aquila) in order to pick up electric signals ranging from 0.3 to 300 kHz, magnetic signals from 0.3 to 30 kHz and seismoacoustic signals by means of three geophones with natural frequencies of 0.3 kHz, 25 kHz and 150 kHz. Data are recorded every ten minutes on a solid state memory. The analysis of the data allows us to establish the existence of electromagnetic fields of distant origin connected with broadcastings and with tropical lightning activity and the discontinuous presence of local electric and magnetic signals, coupled with seismoacoustic ones, connected with weather events. A qualitative explanation of these near fields is given.

scholarly journals The map of permanent natural electric field of Russia

2020 ◽  
pp. 42-50
Author(s):  
A. N. Dmitriev
Keyword(s):  
Electric Potential ◽  
Electrical Potential ◽  
Ferrous Metal ◽  
Potential Method ◽  
Small Scale ◽  
Seismic Events ◽  
Deep Faults ◽  
Undiscovered Deposits ◽  
Natural Electric Field ◽  
Deep Temperature

The article describes a direct connection between the natural electric potential and the dynamics of the temperature of volcanoes using the examples of observation of the natural electric potential on the surfaces of volcanoes. If the upper part of the volcano is hotter, positive potential anomalies are recorded, and conversely, if the lower part of the volcanoes is hotter, negative anomalies of the same potential are recorded. At the same time, the temperature processes occurring at great depths, as a rule, are closely related to long-lived deep faults. Therefore, observations of the natural potential over these faults will allow controlling the dynamics of deep temperature processes. Given this new direction of the natural potential method and its effective application in the search for non-ferrous metal ores, there is a need to create the map of the natural electrical potential of Russia. As a result, small-scale map would allow us more precise limitation of ore fields and purposefully search for previously undiscovered deposits of metal ores. In addition, a small-scale map would make it possible to most accurately track the development of deep tectonic fault zones and to study them in relation to volcanic activity and seismic events. In this regard, the method of natural electric potential hodograph is considered as one of the possible ways to predict seismic events.

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