ON THE PROBLEM OF IDENTIFICATION OF POSSIBLE PRECURSORS OF STRONG SEISMIC EVENTS IN LOCAL VARIATIONS OF COMPONENTS OF THE VECTOR OF THE GEOMAGNETIC FIELD

2021 ◽  
Vol 22 (3) ◽  
pp. 5-25
Keyword(s):  
Geomagnetic Field ◽  
Seismic Events

scholarly journals Detection of ULF geomagnetic signals associated with seismic events in Central Mexico using Discrete Wavelet Transform

2010 ◽  
Vol 10 (12) ◽  
pp. 2557-2564 ◽  
Author(s):  
O. Chavez ◽  
J. R. Millan-Almaraz ◽  
R. Pérez-Enríquez ◽  
J. A. Arzate-Flores ◽  
A. Kotsarenko ◽  
...  
Keyword(s):  
Wavelet Transform ◽  
Discrete Wavelet Transform ◽  
Geomagnetic Field ◽  
Seismic Activity ◽  
Seismic Event ◽  
Low Frequency ◽  
Field Measurements ◽  
Seismic Events ◽  
Discrete Wavelet ◽  
Fluxgate Magnetometer

Abstract. The geomagnetic observatory of Juriquilla Mexico, located at longitude –100.45° and latitude 20.70°, and 1946 m a.s.l., has been operational since June 2004 compiling geomagnetic field measurements with a three component fluxgate magnetometer. In this paper, the results of the analysis of these measurements in relation to important seismic activity in the period of 2007 to 2009 are presented. For this purpose, we used superposed epochs of Discrete Wavelet Transform of filtered signals for the three components of the geomagnetic field during relative seismic calm, and it was compared with seismic events of magnitudes greater than Ms > 5.5, which have occurred in Mexico. The analysed epochs consisted of 18 h of observations for a dataset corresponding to 18 different earthquakes (EQs). The time series were processed for a period of 9 h prior to and 9 h after each seismic event. This data processing was compared with the same number of observations during a seismic calm. The proposed methodology proved to be an efficient tool to detect signals associated with seismic activity, especially when the seismic events occur in a distance (D) from the observatory to the EQ, such that the ratio D/ρ < 1.8 where ρ is the earthquake radius preparation zone. The methodology presented herein shows important anomalies in the Ultra Low Frequency Range (ULF; 0.005–1 Hz), primarily for 0.25 to 0.5 Hz. Furthermore, the time variance (σ2) increases prior to, during and after the seismic event in relation to the coefficient D1 obtained, principally in the Bx (N-S) and By (E-W) geomagnetic components. Therefore, this paper proposes and develops a new methodology to extract the abnormal signals of the geomagnetic anomalies related to different stages of the EQs.

scholarly journals Wavelet-based Characterization of Seismicity and Geomagnetic Disturbances in the South Sandwich Microplate Area

2021 ◽  
Vol 60 (4) ◽  
pp. 320-332
Author(s):  
Patricia Larocca ◽  
M.A. Arecco ◽  
M. Mora
Keyword(s):  
Geomagnetic Field ◽  
Seismic Events ◽  
South American ◽  
The South ◽  
Geomagnetic Disturbances ◽  
Mechanical Motion ◽  
South American Plate ◽  
Cycle 24 ◽  
One Year

This paper analyzes geomagnetic disturbances associated with seismic events in the northern transcurrent margin of the South Sandwich microplate and South American plate, with their epicenter at distances within 350 km from King Edward Point geomagnetic observatory on the archipelago of the Georgias del Sur islands. Geomagnetic field records measured over a one-year period in three observatories of the INTERMAGNET network near the area under study are examined. Anomalous variations in geomagnetic records can be detected within approximately 3 hours before the manifestation of seismic events with a magnitude above 4.4 Mw. Based on the analysis of the differences in horizontal field components among the observatories and the frequency spectrum of the geomagnetic field observations using the wavelet method, oscillations of several nT can be observed before an event, in addition to magnetic peaks with variable amplitude and duration. It is worth noting that, during the period of study, no severe ionospheric effects were recorded as this was a phase of low solar activity (solar cycle 24 minimum). The observation of these potential magnetic precursors suggests that there is a critical preparatory period in a region with geological faults related to the stress generated in the rocks before the built-up energy is released in the hypocenter area, within the lithosphere, which may predict the mechanical motion based on anomalous geomagnetic records.

The anomalous entry of low-rigidity solar cosmic rays into the geomagnetic field

1963 ◽  
Vol 68 (19) ◽  
pp. 5327 ◽  
Author(s):  
S.-I. Akasofu ◽  
W. C. Lin ◽  
J. A. Van Allen
Keyword(s):  
Cosmic Rays ◽  
Geomagnetic Field ◽  
Solar Cosmic Rays

Models of the geomagnetic field and characteristics of magnetic storms

2006 ◽  
Vol 12 (1) ◽  
pp. 64-69
Author(s):  
O.I. Maksimenko ◽  
◽  
L.N. Yaremenko ◽  
O.Ya. Shenderovskaya ◽  
G.V. Melnyk ◽  
...  
Keyword(s):  
Geomagnetic Field ◽  
Magnetic Storms

MicroVolt Variations of The Human Brain (Quantitative Electroencephalography) Display Differential Torque Effects During West-East versus North-South Orientation in the Geomagnetic Field

2016 ◽  
Vol 12 (2) ◽  
pp. 4255-4259
Author(s):  
Michael A Persinger ◽  
David A Vares ◽  
Paula L Corradini
Keyword(s):  
Human Brain ◽  
Geomagnetic Field ◽  
Neuronal Cell ◽  
Single Subject ◽  
Additional Energy ◽  
Actual Measurement ◽  
Neuronal Processes ◽  
Basic Physics ◽  
Order Of Magnitude ◽  
The Moment

                The human brain was assumed to be an elliptical electric dipole. Repeated quantitative electroencephalographic measurements over several weeks were completed for a single subject who sat in either a magnetic eastward or magnetic southward direction. The predicted potential difference equivalence for the torque while facing perpendicular (west-to-east) to the northward component of the geomagnetic field (relative to facing south) was 4 μV. The actual measurement was 10 μV. The oscillation frequency around the central equilibrium based upon the summed units of neuronal processes within the cerebral cortices for the moment of inertia was 1 to 2 ms which are the boundaries for the action potential of axons and the latencies for diffusion of neurotransmitters. The calculated additional energy available to each neuron within the human cerebrum during the torque condition was ~10-20 J which is the same order of magnitude as the energy associated with action potentials, resting membrane potentials, and ligand-receptor binding. It is also the basic energy at the level of the neuronal cell membrane that originates from gravitational forces upon a single cell and the local expression of the uniaxial magnetic anisotropic constant for ferritin which occurs in the brain. These results indicate that the more complex electrophysiological functions that are strongly correlated with cognitive and related human properties can be described by basic physics and may respond to specific geomagnetic spatial orientation.

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