Contaminated Effect of Geomagnetic Storms on Pre-Seismic Atmospheric and Ionospheric Anomalies during Imphal Earthquake

Biswas, Sagardweep; Kundu, Subrata; Ghosh, Soujan; Chowdhury, Swati; Yang, Shih-Cheng; Hayakawa, Masashi; Chakraborty, Suman; Chakrabarti, Sandip K.; Sasmal, Sudipta

doi:10.4236/ojer.2020.95022

Cited by 14 publications

(17 citation statements)

References 47 publications

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“…We have shown that MSTID, a typical space weather phenomenon is deeply related to pre-seismic ionospheric anomaly identified as a deceleration in propagation velocity of MSTID before large earthquakes. Similar interrelation between space weather phenomena such as geomagnetic storms and preseismic atmospheric and ionospheric anomalies is also reported [21].…”

Section: Discussionsupporting

confidence: 77%

Capability of TEC correlation Analysis and Deceleration at Propagation Velocities of Medium-Scale Traveling Ionospheric Disturbances: Preseismic Anomalies before the Large Earthquakes

Umeno¹,

Nakabayashi²,

Iwata³

et al. 2021

OJER

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Section: Discussionsupporting

confidence: 77%

Capability of TEC correlation Analysis and Deceleration at Propagation Velocities of Medium-Scale Traveling Ionospheric Disturbances: Preseismic Anomalies before the Large Earthquakes

Umeno¹,

Nakabayashi²,

Iwata³

et al. 2021

OJER

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“…In particular, a weak geomagnetic activity may be misleading criterion concerning the origin of EQ EM precursory phenomena. Recently, Biswas et al (2020) presented a paper, where they tried to separate the contamination in ionospheric parameters due to geomagnetic storm and acoustics parameters.…”

Section: Discussionmentioning

confidence: 99%

On the Origin of ULF Magnetic Waves Before the Taiwan Chi-Chi 1999 Earthquake

Anagnostopoulos

2021

Front. Earth Sci.

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The ultra low frequency (ULF) electromagnetic (EM) wave activity usually recorded on Earth’s ground has been found to depend on various types of space weather. In addition ULF waves observed before an earthquake have been hypothesized to be a result of geotectonic processes. In this study we elaborate for the first time the origin of sub-ULF (<1 msec) magnetic field waves before an earthquake (Chi-Chi/Taiwan, 20.9.1999) by comparing simultaneously obtained measurements in the interplanetary space (ACE satellite) and on the Earth’s ground (Taiwan). The most striking result of our data analysis, during a period of 7 weeks, is that the detection of four groups of sub-ULF waves in Taiwan coincide in time with the quasi-periodic detection of two solar wind streams by the satellite ACE with approximately the solar rotation period (∼28 days). The high speed solar wind streams (HSSs) in the interplanetary space were accompanied by sub-ULF Alfvén wave activity, quasi-periodic southward IMF and solar wind density perturbations, which are known as triggering agents of magnetic storm activity. The four HSSs were followed by long lasting decreases in the magnetic field in Taiwan. The whole data set examined in this study strongly suggest that the subULF magnetic field waves observed in Taiwan before the Chi-Chi 1999 earthquake is a normal consequence of the incident of HSSs to the magnetosphere. We provide some observational evidence that the sub-ULF electromagnetic radiation on the Earth was most probably a partner to (not a result of) geotectonic processes preparing the Taiwan 1999 earthquake.

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“…Moreover, it is also known that the ionosphere is sensitive to EQ preparation processes, and constitutes a very promising means of short-term EQ prediction [1]. Different techniques and methods have been used to reveal any kinds of statistical anomalies or any indication of specific physical meaning, by analyzing the observables related to EQ preparation processes, not only in phenomena directly related to the lithosphere, but also with phenomena in the atmosphere and the ionosphere [2,11,12]. A few hypotheses for lithosphere-atmosphere-ionosphere coupling (LAIC) have been introduced in order to clarify the involved physical mechanisms, but LAIC is still poorly understood at the moment [2,13].…”

Section: Introductionmentioning

confidence: 99%

“…Figure12. MCF analysis of a CW, identified in the VLF recordings of the ISR−UWA propagation path prior to the Samos EQ on October 2020.…”

mentioning

confidence: 99%

Statistical and Criticality Analysis of the Lower Ionosphere Prior to the 30 October 2020 Samos (Greece) Earthquake (M6.9), Based on VLF Electromagnetic Propagation Data as Recorded by a New VLF/LF Receiver Installed in Athens (Greece)

Politis

Potirakis

Contoyiannis

et al. 2021

Entropy

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In this work we present the statistical and criticality analysis of the very low frequency (VLF) sub-ionospheric propagation data recorded by a VLF/LF radio receiver which has recently been established at the University of West Attica in Athens (Greece). We investigate a very recent, strong (M6.9), and shallow earthquake (EQ) that occurred on 30 October 2020, very close to the northern coast of the island of Samos (Greece). We focus on the reception data from two VLF transmitters, located in Turkey and Israel, on the basis that the EQ’s epicenter was located within or very close to the 5th Fresnel zone, respectively, of the corresponding sub-ionospheric propagation path. Firstly, we employed in our study the conventional analyses known as the nighttime fluctuation method (NFM) and the terminator time method (TTM), aiming to reveal any statistical anomalies prior to the EQ’s occurrence. These analyses revealed statistical anomalies in the studied sub-ionospheric propagation paths within ~2 weeks and a few days before the EQ’s occurrence. Secondly, we performed criticality analysis using two well-established complex systems’ time series analysis methods—the natural time (NT) analysis method, and the method of critical fluctuations (MCF). The NT analysis method was applied to the VLF propagation quantities of the NFM, revealing criticality indications over a period of ~2 weeks prior to the Samos EQ, whereas MCF was applied to the raw receiver amplitude data, uncovering the time excerpts of the analyzed time series that present criticality which were closest before the Samos EQ. Interestingly, power-law indications were also found shortly after the EQ’s occurrence. However, it is shown that these do not correspond to criticality related to EQ preparation processes. Finally, it is noted that no other complex space-sourced or geophysical phenomenon that could disturb the lower ionosphere did occur during the studied time period or close after, corroborating the view that our results prior to the Samos EQ are likely related to this mainshock.

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Contaminated Effect of Geomagnetic Storms on Pre-Seismic Atmospheric and Ionospheric Anomalies during Imphal Earthquake

Cited by 14 publications

References 47 publications

Capability of TEC correlation Analysis and Deceleration at Propagation Velocities of Medium-Scale Traveling Ionospheric Disturbances: Preseismic Anomalies before the Large Earthquakes

Capability of TEC correlation Analysis and Deceleration at Propagation Velocities of Medium-Scale Traveling Ionospheric Disturbances: Preseismic Anomalies before the Large Earthquakes

On the Origin of ULF Magnetic Waves Before the Taiwan Chi-Chi 1999 Earthquake

Statistical and Criticality Analysis of the Lower Ionosphere Prior to the 30 October 2020 Samos (Greece) Earthquake (M6.9), Based on VLF Electromagnetic Propagation Data as Recorded by a New VLF/LF Receiver Installed in Athens (Greece)

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