Singular spectral analysis applied to magnetotelluric time series collected at Medea Geomagnetic Observatory (Algeria)—an attempt to discriminate earthquake-related electromagnetic signal

Kasdi, Ahmed Seddik; Bouzid, Abderrezak; Hamoudi, Mohamed; Abtout, Abdeslam

doi:10.1007/s12517-022-10438-2

Cited by 3 publications

(1 citation statement)

References 45 publications

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“…In normal conditions, we measure three field components of magnetic field, but additional measurements of electric field components are of special importance in estimating the whole wave characteristics of amplitude ratios and phase differences [67] [80]. This kind of multi-stationed network will enable us to perform sophisticated signal processing methods including principal component analysis [81], singular value decomposition [82] [83], direction finding (either goniometric or gradient [84] [85] or polarization ellipse [86]), which will definitely increase the credibility of the observed seismogenic ULF emissions after eliminating the space weather effects. All of the above-mentioned methods are expected to improve the credibility of seismogenic ULF emissions, and also for better understanding of their association with EQ activity, but no signal method can solve all of the above-mentioned problems and sophisticated combination of results by a few methods play an essential role in solving the problem.…”

Section: Future Direction Of Ulf Emissions As a Reliable Diagnostic Toolmentioning

confidence: 99%

Seismogenic ULF/ELF Wave Phenomena: Recent Advances and Future Perspectives

Hayakawa¹,

Schekotov²,

Izutsu³

et al. 2023

OJER

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There has been enormous progress in the field of electromagnetic phenomena associated with earthquakes (EQs) and EQ prediction during the last three decades, and it is recently agreed that electromagnetic effects do appear prior to an EQ. A few phenomena are well recognized as being statistically correlated with EQs as promising candidates for short-term EQ predictors: the first is ionospheric perturbation not only in the lower ionosphere as seen by subionospheric VLF (very low frequency, 3 kHz < f < 30 kHz)/LF (low frequency, 30 kHz < f < 300 kHz) propagation but also in the upper F region as detected by ionosondes, TEC (total electron content) observations, satellite observations, etc, and the second is DC earth current known as SES (Seismic electric signal). In addition to the above two physical phenomena, this review highlights the following four physical wave phenomena in ULF (ultra low frequency, frequency < 3 Hz)/ELF

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Section: Future Direction Of Ulf Emissions As a Reliable Diagnostic Toolmentioning

confidence: 99%

Seismogenic ULF/ELF Wave Phenomena: Recent Advances and Future Perspectives

Hayakawa¹,

Schekotov²,

Izutsu³

et al. 2023

OJER

View full text Add to dashboard Cite

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Numerical modeling of the co-seismic electromagnetic signals observed during the 2014 Mw 4.9 Hammam Melouane earthquake, Northern Algeria

Kasdi

Bouzid

Hamoudi

et al. 2022

Journal of Applied Geophysics

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Observation of Ultra-Low-Frequency Wave Effects in Possible Association with the Fukushima Earthquake on 21 November 2016, and Lithosphere–Atmosphere–Ionosphere Coupling

Hayakawa

Schekotov

Yamaguchi³

et al. 2023

Atmosphere

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The study presents seismogenic ULF (ultra-low-frequency) wave effects, as observed at our own new magnetic observatory at Asahi (geographic coordinates: 35.770° N, 140.695° E) in Chiba Prefecture. Our target earthquake (EQ) is a huge one offshore of Fukushima prefecture (37.353° N, 141.603° E) with a magnitude (M) of 7.4, which occurred at 20.59 h on November 21 UT, 2016. As a sampling frequency of 1 Hz was chosen for our induction magnetometer, we could detect both ULF wave effects: ULF radiation from the lithosphere, and the ULF depression effect, indicative of lower ionospheric perturbations. Observing the results of polarization analyses, we detected clear enhancements in ULF (frequency = 0.01–0.03 Hz) lithospheric radiation 14 days, 5 days, and 1 day before the EQ, and also observed a very obvious phenomenon of ULF (0.01–0.03 Hz) depression just 1 day prior to the EQ, which is regarded as the signature of lower ionospheric perturbations. These findings suggest that pre-EQ seismic activity must be present in the lithosphere, and also that the lower ionosphere was very much perturbed by the precursory effects of the Fukushima EQ. These new observational effects from our station have been compared with our previous investigations on different seismogenic topics for the same EQ, including the ULF observations at another magnetic observatory at Kakioka, belonging to the Japan Meteorological Agency (JMA), about 50 km north of our Asahi station, subionospheric VLF/LF propagation data (Japanese and Russian data), AGW (Atmospheric gravity wave) activity in the stratosphere, and satellite observation of particle precipitations. We have found that seismogenic anomalies of different parameters tend to happen just around the EQ day, but mainly before the EQ, and have found the chain-like tendency of the effects of the lithosphere, which seem to propagate upwards the lower ionosphere. Finally, we will try to gain a better understanding of the physical phenomena or mechanisms of the lithosphere–atmosphere–ionosphere coupling (LAIC) process during the EQ preparation phase.

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Singular spectral analysis applied to magnetotelluric time series collected at Medea Geomagnetic Observatory (Algeria)—an attempt to discriminate earthquake-related electromagnetic signal

Cited by 3 publications

References 45 publications

Seismogenic ULF/ELF Wave Phenomena: Recent Advances and Future Perspectives

Seismogenic ULF/ELF Wave Phenomena: Recent Advances and Future Perspectives

Numerical modeling of the co-seismic electromagnetic signals observed during the 2014 Mw 4.9 Hammam Melouane earthquake, Northern Algeria

Observation of Ultra-Low-Frequency Wave Effects in Possible Association with the Fukushima Earthquake on 21 November 2016, and Lithosphere–Atmosphere–Ionosphere Coupling

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