TITLE:
A Multi-Parametric Investigation of Seismogenic Signals: A Case Study of the 2018 Aomori Earthquake (Mw 6.2)
AUTHORS:
Kousik Nanda, Bhuvnesh Brawar, Masashi Hayakawa, Yasuhide Hobara, Stelios M. Potirakis, Ajeet K. Maurya, Uma Pandey, Abhirup Datta, Sudipta Sasmal
KEYWORDS:
Lithosphere-Atmosphere-Ionosphere Coupling, Multi-Parameter Analysis, Ground and Space-Based Study, Pre-, Co-Post-Seismic Impressions
JOURNAL NAME:
Open Journal of Earthquake Research,
Vol.15 No.2,
May
14,
2026
ABSTRACT: We present a comprehensive multi-parametric analysis of Lithosphere-Atmosphere-Ionosphere Coupling (LAIC) processes associated with the 24 January 2018 Aomori earthquake (
M~6.2
), located off the east coast of northern Honshu, Japan. Thermal observations reveal coherent pre-seismic irregularities in near-surface air temperature, relative humidity, and atmospheric chemical potential (ACP), with notable variations emerging 1 - 2 days prior to the event, followed by co-seismic intensification and rapid post-seismic relaxation. Acoustic channel analysis indicates enhanced atmospheric gravity wave (AGW) activity derived from ERA5 reanalysis, with significant amplification beginning 3 - 5 days before the earthquake, peaking around the event time, and gradually diminishing afterward. Electromagnetic and ionospheric signatures are evident in both lower and upper atmospheric regions. Very-Low-Frequency (VLF/LF) sub-ionospheric observations exhibit statistically significant pre-seismic anomalies, particularly one day prior to the earthquake, while GNSS-based Vertical Total Electron Content (VTEC) shows clear enhancements during the preparatory phase and maximum deviation on the earthquake day. Global Ionospheric Map (GIM) analysis further confirms localized ionospheric perturbations centered around the epicentral region, with a clear spatial decay away from the source. All observations were obtained under geomagnetically quiet conditions, ensuring minimal external influence. Together, these thermal, acoustic, and electromagnetic signatures indicate a consistent sequence of pre-seismic build-up, co-seismic response, and post-seismic recovery, providing a robust multi-channel imprint of the Aomori earthquake and highlighting the importance of integrated multi-parametric approaches for understanding earthquake preparatory processes.