The effect of a compact ionosphere disturbance over the earthquake: A Focus on Schumann resonance

Abstract

We model perturbations of vertical electric and horizontal magnetic fields of Schumann resonance by a localized seismogenic non-uniformity in the Earth-ionosphere cavity with simultaneous accounting for the day-night non-uniformity. The source and receiver are placed at the same meridian and the latitudes covering 22.5° N and 22.5° S. The propagation path is positioned at the night (60° E) or the dayside (120° E) of morning terminator. The localized nonuniformity moves either along or across the propagation path. The full wave solution is used in the form of Riccati equation for finding the propagation parameters. The spectral components of fields are computed with the 2D (two dimensional) telegraph equations. Numerical estimates were obtained of the impact of the localized ionosphere non-uniformity on the electric and magnetic field amplitudes at a set of Schumann resonance frequencies for various positions of disturbances relative to the propagation path. It is shown that the impact of compact nonuniformity grows with increasing frequency. Field modifications are of interference nature. The day-night asymmetry provides a minor impact, and one may neglect this non-uniformity. The model was applied to interpret observations with a point source in Southeast Asia, Africa, or in South America. The observer was positioned at the Moshiri observatory, Japan. The earthquake focus modifying the conductivity of mesosphere was located at Taiwan. Perturbations of amplitude spectra of Schumann resonance were computed and their similarity to the observations was demonstrated.

Scattering of Extremely Low Frequency Electromagnetic Waves by a Localized Seismogenic Ionospheric Perturbation: Observation and Interpretation

“…Still, these reflect both qualitative and quantitative features observed experimentally. These already published data show that seismogenic modifications in the SR spectra might be successfully explained by radio wave reflection from the atmospheric nonuniformity above the EQ position (Galuk et al, 2019; Nickolaenko et al, 2018a, 2018b; Nickolaenko & Hayakawa, 2013; Nickolaenko et al, 2006). The conductivity modifications of this kind are able to influence only ELF radio waves.…”

Extremely Low Frequency (ELF) Electromagnetic Signals as a Possible Precursory Warning of Incoming Seismic Activity

“…The main source of the Schumann resonances is lightning activity, occurring in the tropical belt around the world, creating electromagnetic waves that propagate within the cavity [38][39][40]. For extensive details on the subject of SR, the reader may refer to the books by Nickolaenko and Hayakawa [41,42] and relevant articles [43][44][45][46][47][48][49][50] where the theory of SR physics, applications, and technical details about data recording were analyzed in detail.…”

Recent Advances and Challenges in Schumann Resonance Observations and Research

“…S. S. et al [103] studied the changes in SR signals 15 and 5 days before and after earthquake events, and concluded that SR anomalies appeared several hours earlier than ionospheric anomalies. A. P. Nickolaenko, M. Hayakawa et al [104][105][106] used ELF observation data from Nakatsugawa and Moshiri stations in Japan to report significant SR anomalies before and after multiple earthquakes and found that the estimated arrival angle of the abnormal signal was consistent with the azimuth angle from the station to the epicenter, proving that seismic electromagnetic radiation is the main cause of SR anomalies. Christofilakis et al [107] used the close ELF observation records obtained during the earthquake duration (the ground observation station is only 365 km from the epicenter) to detect the extreme electromagnetic events before and after the occurrence of seismicity and summarized the laws of these extreme electromagnetic events.…”