Geomagnetic Variations during Strong Earthquakes

Спивак, А. А.; Рябова, С. А.

doi:10.1134/s1069351319060077

Cited by 15 publications

(5 citation statements)

References 22 publications

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“…On the second day after the earthquake, there was a region of decreased values (about 16 %) (Figure 6). Davidenko, Pulinets [2019] observed an increase in the F2-layer critical frequency (up to 24 %) from 22 to 7 LT, contrary to our observations 24 hours before the earthquake. The authors did not note decreased values after the earthquake.…”

Section: Analysis Of Resultscontrasting

confidence: 99%

“…Recent studies have revealed a relationship between geospheres, which also manifests itself in the lithosphere-atmosphere-ionosphere-magnetosphere coupling. Several days or hours before an earthquake, numerous abnormal changes occur in medium and electromagnetic field parameters [Liperovsky et al, 2008;Pulinets et al, 2015;Korsunova et al, 2013]. despite numerous studies in this field of research, there is, however, no generally accepted point of view allowing us to interpret ionospheric observations over seismically active regions, although there are several hypotheses.…”

Section: Introductionmentioning

confidence: 99%

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Variations of ionospheric and geomagnetic field parameters during the June 18, 2013 Bachat earthquake

Belinskaya

Kovalev

Semakov

et al. 2021

Solar-Terrestrial Physics

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The paper presents the results of a study of variations in ionospheric parameters and local magnetic constant before, during, and after the Vachat earthquake, which occurred on June 18, 2013 at 23:02 UT (June 19, 2013 at 06:02 LT) with a magnitude 5.3–5.6 and epicenter coordinates 54.29 ° N, 86.17 ° E. We have used data from IPGG SB RAS and TSU ionospheric stations and INTERMAGNET geomagnetic observatories. We have established that in the period preceding the earthquake there was a rather sharp increase in the magnetic moment, and in the subsequent period there was an equally sharp decrease in the magnetic moment. It is noted that the analysis of the daily average values of the local magnetic constant is the most promising for searching for geomagnetic precursors of earthquakes. We have found a low strong sporadic layer Es for two days before the event, the like of which was not observed for 15 days before and 15 days after the event. In addition, on the days preceding the shock, the background values of the F2-layer critical frequency were larger by more than 20% at the local pre-event hours. On the second day after the earthquake, there appeared a night-time region of low values (about 14%), which persisted until the morning of the third day.

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Section: Analysis Of Resultscontrasting

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Variations of ionospheric and geomagnetic field parameters during the June 18, 2013 Bachat earthquake

Belinskaya

Kovalev

Semakov

et al. 2021

Solar-Terrestrial Physics

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“…It was suggested that the probable mechanism of this effect is the excitation of the ionosphere in the epicentral region by acoustic-gravity waves (AGWs) resulting from movements of the earth's crust [Adushkin and Spivak, 2021;Chernogor, 2019]. Based on observations at mid-latitude station Mikhnevo (MKH) [Spivak and Ryabova, 2019] claimed that strong EQs are accompanied at far-distant stations by geomagnetic long-period disturbances (period ~5-20 min) with amplitude 2-4 nT (see example in Figure 4, where the reported midlatitude long-period disturbance is marked by the rounded red box). The authors suggested that these disturbances of the magnetic field are caused either by underground dynamic processes or disturbances in the Earth's ionosphere over the epicenter.…”

Section: Long-period Geomagnetic Disturbances Generated By Strong Eqsmentioning

confidence: 99%

“…Figure4. The long-period geomagnetic disturbance detected at mid-latitudes (marked by a red empty box) that was claimed in[Spivak and Ryabova, 2019] to be associated with strong EQ (marked by a vertical dashed line). The geomagnetic latitude and longitude are indicated near the station codes at left-hand vertical axis.…”

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confidence: 99%

A Closer Cooperation between Space and Seismology Communities – a Way to Avoid Errors in Hunting for Earthquake Precursors

Pilipenko,

Shiokawa

2024

Russian Journal of Earth Sciences

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The space physicists and the earthquake (EQ) prediction community exploit the same instruments – magnetometers, but for different tasks: space physicists try to comprehend the global electrodynamics of near-Earth space on various time scales, whereas the seismic community develops electromagnetic methods of short-term EQ prediction. The lack of deep collaboration between those communities may result sometimes in erroneous conclusions. In this critical review, we demonstrate some incorrect results caused by a neglect of specifics of geomagnetic field evolution during space weather activation. The considered examples comprise: Magnetic storms as a trigger of EQs; ULF waves as a global EQ precursor; Geomagnetic impulses before seismic shocks; Long-period geomagnetic disturbances generated by strong EQs; Discrimination of underground ULF sources by amplitude-phase gradients; Depression of ULF power as a short-term EQ precursor; and Detection of seimogenic emissions by satellites. To verify the reliability of the above widely disseminated results data from available arrays of fluxgate and search-coil magnetometers have been re-analyzed. In all considered events, the “anomalous” geomagnetic field behavior can be explained by global geomagnetic activity, and it is apparently not associated with seismic activity. This critical review does not claim that ULF electromagnetic field cannot be used as a sensitive indicator of the EQ preparation processes, but we suggest that both communities must cooperate their studies more tightly using data exchange, combined usage of magnetometer networks, organization of CDAW for unique events, etc.

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“…One of the most elusive objectives for seismology is being able to predict an earthquake in the short term. There are numerous studies reporting relationships between earthquakes and physical phenomena, such as significant mechanical effects in the focal area of an earthquake, whether rock changes or deformation; changes in rock properties and stress-deformation state; changes in the chemical composition and/or temperature of the groundwater; electrophysical properties of the medium; increased emanations of natural radon and excitation of seismic signals: all of this affects the regimes of geophysical fields (Hayakawa et al 2010;Takeuchi et al 2012, Varotsos et al, 2013Spivak and Riabova, 2019).…”

Section: Introductionmentioning

confidence: 99%

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

Larocca

Arecco²,

Mora³

2021

GeofInt

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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.

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Geomagnetic Variations during Strong Earthquakes

Cited by 15 publications

References 22 publications

Variations of ionospheric and geomagnetic field parameters during the June 18, 2013 Bachat earthquake

Variations of ionospheric and geomagnetic field parameters during the June 18, 2013 Bachat earthquake

A Closer Cooperation between Space and Seismology Communities – a Way to Avoid Errors in Hunting for Earthquake Precursors

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

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