The LAI Coupling Associated with the M6 Luxian Earthquake in China on 16 September 2021

Chen, Chieh‐Hung; Sun, Yang‐Yi; Lin, Kai Hsin; Liu, Jing; Wang, Yali; Gao, Yongxin; Zhang, Dixin; Xu, Ruochen; Chen, Cong

doi:10.3390/atmos12121621

Cited by 10 publications

(9 citation statements)

References 45 publications

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“…Based only on the comparison of observational results with theoretical studies in this paper, it is rather difficult for us to suggest which hypothesis is more appropriate than the other for our present case. However, there has been accumulated a lot of evidence on the AGW hypothesis [Miyake et al, 2002;Shvets et al, 2004;Rozhnoi et al, 2013;Yang et al, 2019Lizunov et al, 2020;Carbone et al, 2021;Chen et al, 2021;Kundu et al, 2022], so we try to interpret our observational results on SR with the use of this AGW hypothesis. So, the profile "compression" might be explained in the following way.…”

Section: Discussionmentioning

confidence: 99%

Schumann resonance anomalies associated with two (M~7) Tohoku offshore earthquakes in the spring of 2021

Hayakawa,

Izutsu,

Nickolaenko

et al. 2023

Annals of Geophysics

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ABSTRACT. We describe the Schumann resonance (SR) anomalies associated with two earthquakes (EQs) observed in Japan in the spring of 2021. SR is the global electromagnetic phenomenon observed in the ELF (extremely low frequency) band, and its resonance peaks are observed in the power spectra on natural radio noise at frequencies of 8, 14, 20, Hz, etc. The natural source of ELF radiation is the global lightning activity occurring in the Earth-ionosphere cavity. The anomalies were observed for the first time in Japan for the EQs in Taiwan when the distance between the observatory and the EQ epicenter was a few Mm (1 Mm = 1000 km). Recently, a new SR anomaly was addressed, related to nearby (a few hundred km) EQs (Hayakawa et al., 2019, 2020a,b). This paper presents the SR anomalies observed in the vicinity of Nagoya-city for two relatively close (~500 km) successive EQs with magnitude around 7 that occurred offshore the Tohoku area in Japan. The anomaly is characterized by the noticeable simultaneous increase or decrease in the amplitudes of three SR modes. This SR unusual behavior was observed prior to and after each of the two EQs that occurred in February and March, 2021. Observational data were interpreted in the model of seismogenic perturbations of the lower ionospheric conductivity profile. Model computations imply the full-wave solution of the ELF electromagnetic problem in the form of the Riccati equation and the 2D (two dimensional) telegraph equations. We show that observed disturbances in the SR power spectra might be attributed to two types of seismogenic modifications in the lower ionospheric profile: the compression or the expansion of the vertical profiles of mesospheric conductivity over the EQ epicenter.

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Section: Discussionmentioning

confidence: 99%

Schumann resonance anomalies associated with two (M~7) Tohoku offshore earthquakes in the spring of 2021

Hayakawa,

Izutsu,

Nickolaenko

et al. 2023

Annals of Geophysics

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“…We suppose that the persistent ground vibrations are capable of modulating variations in atmosphere and sequentially changing TEC in the ionosphere. A M6 earthquake occurred around the MVP-LAI system on 16 September 2021 32 . Pre-earthquake ground vibrations and crustal deformation persist a few months in a wide area that has been reported 33 – 36 .…”

Section: Discussionmentioning

confidence: 99%

Resonant signals in the lithosphere–atmosphere–ionosphere coupling

Chen

Sun

Zhang

et al. 2022

Sci Rep

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A study in the lithosphere, atmosphere and ionosphere (LAI) coupling often troubles scientists due to a certain distance between distinct instruments, which monitor geophysical parameters in different spheres. An instrumental system was established in southwest China (Leshan; LESH) for monitoring vibrations and perturbations in LAI (MVP-LAI). A ground-based Global Navigation Satellite System (GNSS) receiver at the YADU station locates ~ 260 km away that continuously receives electromagnetic signals transmitted from the BeiDou navigation System (BDS) geostationary satellites to monitor the total electron content (TEC) at the ionospheric pierce point right over the MVP-LAI system. The employment of YADU TEC benefits in elimination of possible shaking effects happening on multiple instruments at the LESH station and mitigation the troubles due to the discrepancy in observation places. Through a stacking process on the retrieved data for increase of signal to noise ratios, a novel phenomenon of the resonant LAI coupling at a fundamental mode of ~ 3.4 mHz and its multiples persists in ground vibrations, atmospheric pressure and TEC retrieved from the MVP-LAI system and the YADU station. The retrieved data share frequencies during the operational period of 1.5 months that is irrelevant to obvious events in the lithosphere, atmosphere and ionosphere. The persistence of the resonant LAI coupling is essential in the Earth’s system.

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“…Enhancements of the amplitudes at frequencies vary from low to high (~5 × 10 -3 Hz), which can be consistently observed in the seismic and TEC data (Figures 3a and d). While the tendency of enhanced amplitudes to occur at high frequencies is consistent across major earthquakes worldwide , Chen et al, 2021c, the inference that TEC perturbations are triggered by ground vibrations lacks observational evidence linking changes on the ground to those in space.…”

Section: Seismo-lai Coupling Associated With the 2021 M74 Maduo Earth...mentioning

confidence: 99%

Double resonance in seismo-lithosphere-atmosphere-ionosphere coupling

Chen,

Sun,

Zhang

et al. 2023

Annals of Geophysics

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nvestigations into causal mechanisms behind anomalous pre-earthquake phenomena are considered a promising way of earthquake prediction. Numerous promising channels for seismo-lithosphere-atmosphere-ionosphere coupling have been proposed; however, predicting earthquakes remains a great challenge in the scientific society. Short-period ground vibrations exhibiting frequency characteristics similar to natural frequencies caused by strata failure resonance have recently been detected using tiltmeters embedded in magnetometers prior to earthquakes. These vibrations originate from regions near the epicentres of forthcoming earthquakes and can be simultaneously detected by broadband seismometers and ground-based global navigation satellite system (GNSS) receivers. Unlike the total electron contents (TECs) obtained from orbiting satellites, the vibrations and the identifiable TEC perturbations in data from geostationary satellites of the BeiDou Navigation System share frequencies prior to earthquakes. However, the causal relationship between the vibrations and TEC perturbations remains unclear due to a gap in data observations between the lithosphere and ionosphere. To address this issue, an instrumental array was established to monitor vibrations and perturbations in the lithosphere, atmosphere, and ionosphere. Observational data from the array partially fill the gap, and analytical results show that ground vibrations, air pressure, magnetic fields, and TEC data shared a common frequency of approximately 5 × 10–3 Hz (5 mHz) before major earthquakes. This suggests that the resonant ground vibrations trigger atmospheric resonance before earthquakes. Therefore, the double resonance (crustal and atmospheric resonance) model is a new explanation for the observed anomalies in multiple geophysical parameters in the lithosphere, atmosphere, and ionosphere. Retrieving resonant signals from multiple sources of observational data is a significant challenge, but once this issue is overcome, double resonance may contribute to practical earthquake prediction.

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The LAI Coupling Associated with the M6 Luxian Earthquake in China on 16 September 2021

Cited by 10 publications

References 45 publications

Schumann resonance anomalies associated with two (M~7) Tohoku offshore earthquakes in the spring of 2021

Schumann resonance anomalies associated with two (M~7) Tohoku offshore earthquakes in the spring of 2021

Resonant signals in the lithosphere–atmosphere–ionosphere coupling

Double resonance in seismo-lithosphere-atmosphere-ionosphere coupling

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