Propagation of Seismogenic Electric Currents Through the Earth's Atmosphere

Денисенко, В. В.; Boudjada, M. Y.; Lämmer, H.

doi:10.1029/2018ja025228

Cited by 17 publications

(8 citation statements)

References 18 publications

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“…We notice that several papers have already ruled out the electrostatic hypothesis (see a discussion in Sorokin et al, 2015). Especially in the papers on the critical analysis of the electrostatic channel by Denisenko (2015) and Denisenko et al (2018), they have calculated the penetrations of lithospheric electric field and current into the ionosphere and concluded that the penetrating electric field and current in the ionosphere are negligible. They further suggest that other atmospheric processes such as AGWs should be considered to explain the lithospheric influence on the ionosphere.…”

Section: Introductionmentioning

confidence: 99%

Abnormal Gravity Wave Activity in the Stratosphere Prior to the 2016 Kumamoto Earthquakes

2019

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Earthquake (EQ) prediction is an essential topic in recent geophysics and disaster management. In order to explain EQ precursory phenomena, especially the ionospheric perturbations, a few hypotheses have been proposed as the mechanism of lithosphere‐atmosphere‐ionosphere coupling. The most reliable seems to be the atmospheric gravity wave (AGW) hypothesis, because a lot of subionospheric very low frequency (VLF) observations and also ground surface measurements support this hypothesis. However, no direct signature of AGW activity in the middle atmosphere has been yet obtained. So in this study, we have used the ERA5 reanalysis data to investigate the tempo‐spatial evolution of stratospheric AGW activity before a recent huge seismic event of the 2016 Kumamoto EQ on 15 April (Mw7.2). It was found that the AGW potential energy is enhanced significantly during about 1 week before the EQ. The enhancement was mainly distributed around the EQ epicenter and expanded toward eastern Japan. The AGW activity was highest around 11 April, then it calmed down and returned to the background level right before the EQ. These results were compared with the subionospheric VLF observations during the same period, and then the tempo‐spatial evolutions of the lower ionospheric perturbation are found to be very consistent with the stratospheric behavior. The present paper reports on the first finding that the abnormal AGW activity in the stratosphere is detected before a major EQ, and the coincidence of stratospheric AGW activity with VLF subionospheric perturbations provides further support to the AGW hypothesis of the lithosphere‐atmosphere‐ionosphere coupling process.

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Section: Introductionmentioning

confidence: 99%

Abnormal Gravity Wave Activity in the Stratosphere Prior to the 2016 Kumamoto Earthquakes

2019

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“…A further introduction to these hypotheses can be found in [ 2 , 22 ]. A series of critical studies [ 23 , 24 , 25 , 26 ] has pointed out that the electric field/current, as proposed in the first chemical and the third electrostatic channel is weak, and that the penetration from the lithosphere into the ionosphere is negligible. Additionally, as compared with the first chemical and the third electrostatic channel, much observational evidence has been mainly accumulated in the subionospheric VLF/LF data to support the second AGW hypothesis [ 12 ], and thus we think that the AGW channel is the most promising candidate as the LAIC mechanism.…”

Section: Introductionmentioning

confidence: 99%

Gravity Wave Activity in the Stratosphere before the 2011 Tohoku Earthquake as the Mechanism of Lithosphere-atmosphere-ionosphere Coupling

Yang

Hayakawa

2020

Entropy

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The precursory atmospheric gravity wave (AGW) activity in the stratosphere has been investigated in our previous paper by studying an inland Kumamoto earthquake (EQ). We are interested in whether the same phenomenon occurs or not before another major EQ, especially an oceanic EQ. In this study, we have examined the stratospheric AGW activity before the oceanic 2011 Tohoku EQ (Mw 9.0), while using the temperature profiles that were retrieved from ERA5. The potential energy (EP) of AGW has enhanced from 3 to 7 March, 4–8 days before the EQ. The active region of the precursory AGW first appeared around the EQ epicenter, and then expanded omnidirectionally, but mainly toward the east, covering a wide area of 2500 km (in longitude) by 1500 km (in latitude). We also found the influence of the present AGW activity on some stratospheric parameters. The stratopause was heated and descended; the ozone concentration was also reduced and the zonal wind was reversed at the stratopause altitude before the EQ. These abnormalities of the stratospheric AGW and physical/chemical parameters are most significant on 5–6 March, which are found to be consistent in time and spatial distribution with the lower ionospheric perturbation, as detected by our VLF network observations. We have excluded the other probabilities by the processes of elimination and finally concluded that the abnormal phenomena observed in the present study are EQ precursors, although several potential sources can generate AGW activities and chemical variations in the stratosphere. The present paper shows that the abnormal stratospheric AGW activity has also been detected even before an oceanic EQ, and the AGW activity has obliquely propagated upward and further disturbed the lower ionosphere. This case study has provided further support to the AGW hypothesis of the lithosphere-atmosphere-ionosphere coupling process.

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“…Considering the electromagnetic channel, difficulties are encountered in simulation of the penetrating electric field and current through the atmosphere. Models [60][61][62] show that the field penetrating into the ionosphere is several orders of magnitude smaller than required. The mechanism based on gravity waves [13] cannot be discarded as well.…”

Section: Discussionmentioning

confidence: 97%

Ionosonde Data Analysis in Relation to the 2016 Central Italian Earthquakes

et al. 2020

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Ionospheric characteristics and crustal earthquakes that occurred in 2016 next to the town of Amatrice, Italy are studied together with the previous events that took place from 1984 to 2009 in Central Italy. The earthquakes with M larger than 5.5 and epicentral distances from the ionosonde less than 150 km were selected for the analysis. A multiparametric approach was applied using variations of sporadic E-layer parameters (the height and the transparency frequency) together with variations of the F2 layer critical frequency foF2 at the Rome ionospheric observatory. Only ionospheric data under quiet geomagnetic conditions were considered. The inclusion of new 2016 events has allowed us to clarify the earlier-obtained seismo-ionospheric empirical relationships linking the distance in space (km) and time (days) between the ionospheric anomaly and the impending earthquake, with its magnitude. The improved dependencies were shown to be similar to those obtained in previous studies in different parts of the world. The possibility of using the obtained relationships for earthquake predictions is discussed.

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Propagation of Seismogenic Electric Currents Through the Earth's Atmosphere

Cited by 17 publications

References 18 publications

Abnormal Gravity Wave Activity in the Stratosphere Prior to the 2016 Kumamoto Earthquakes

Abnormal Gravity Wave Activity in the Stratosphere Prior to the 2016 Kumamoto Earthquakes

Gravity Wave Activity in the Stratosphere before the 2011 Tohoku Earthquake as the Mechanism of Lithosphere-atmosphere-ionosphere Coupling

Ionosonde Data Analysis in Relation to the 2016 Central Italian Earthquakes

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