Sequential evolution of ionospheric TEC anomalies and acoustic-gravity wave precursors associated with the February 8, 2025, Mw 7.6 Cayman Islands earthquake

IF 1.9 4区地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS

Journal of Atmospheric and Solar-Terrestrial Physics Pub Date : 2025-06-25 DOI:10.1016/j.jastp.2025.106582

Karan Nayak , Rosendo Romero-Andrade , Gopal Sharma , Roberto Colonna

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引用次数: 0

Abstract

This study investigates seismo-ionospheric anomalies associated with the Mw 7.6 Cayman Islands earthquake of February 8, 2025, utilizing GNSS-derived ionospheric Total Electron Content (TEC) parameters, including the Ionospheric Disturbance Index (IDI), Rate of TEC Index (ROTI), Acoustic-Gravity Wave (AGW) oscillations, spatial TEC anomaly maps, and Regional Similarity Index (SI). A structured precursor hierarchy was identified, starting with early AGW disturbances several hours before significant ionospheric perturbations, followed sequentially by deviations in SI, IDI increases, and eventual ROTI turbulence. Spatial TEC anomaly maps demonstrated pronounced negative and positive anomalies closely centered around the epicenter region prior to the earthquake, while co-seismic TEC enhancements clearly correlated with seismic wave propagation. Correlation analysis between indices confirmed a progressive and systematic evolution of ionospheric anomalies, highlighting AGWs as crucial early precursors. Geomagnetic filtering (Dst/Kp) ensured the isolation of seismic-driven ionospheric disturbances from solar and geomagnetic influences. These findings robustly validate GNSS-TEC indices as reliable indicators of seismo-ionospheric processes and emphasize their potential role in earthquake precursor monitoring and hazard mitigation strategies.

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2025年2月8日开曼群岛7.6 Mw地震电离层TEC异常和声重力波前兆的序列演化

本文利用gnss获得的电离层总电子含量（TEC）参数，包括电离层扰动指数（IDI）、TEC指数速率（ROTI）、声重力波（AGW）振荡、空间TEC异常图和区域相似指数（SI），研究了2025年2月8日开曼群岛7.6 Mw地震的地震-电离层异常。我们发现了一个结构化的前体层次，从电离层扰动前几个小时的早期AGW扰动开始，随后是SI偏差、IDI增加和最终的ROTI湍流。空间TEC异常图显示出明显的正、负异常集中在震前震中附近，而同震TEC增强与地震波传播明显相关。各指数的相关分析证实了电离层异常的渐进和系统演化，强调了agw是重要的早期前兆。地磁滤波（Dst/Kp）确保将地震驱动的电离层扰动与太阳和地磁影响隔离开来。这些发现有力地验证了GNSS-TEC指数是地震-电离层过程的可靠指标，并强调了它们在地震前兆监测和减灾战略中的潜在作用。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Atmospheric and Solar-Terrestrial Physics 地学-地球化学与地球物理

CiteScore

4.10

自引率

5.30%

发文量

审稿时长

6 months

期刊介绍： The Journal of Atmospheric and Solar-Terrestrial Physics (JASTP) is an international journal concerned with the inter-disciplinary science of the Earth''s atmospheric and space environment, especially the highly varied and highly variable physical phenomena that occur in this natural laboratory and the processes that couple them. The journal covers the physical processes operating in the troposphere, stratosphere, mesosphere, thermosphere, ionosphere, magnetosphere, the Sun, interplanetary medium, and heliosphere. Phenomena occurring in other "spheres", solar influences on climate, and supporting laboratory measurements are also considered. The journal deals especially with the coupling between the different regions. Solar flares, coronal mass ejections, and other energetic events on the Sun create interesting and important perturbations in the near-Earth space environment. The physics of such "space weather" is central to the Journal of Atmospheric and Solar-Terrestrial Physics and the journal welcomes papers that lead in the direction of a predictive understanding of the coupled system. Regarding the upper atmosphere, the subjects of aeronomy, geomagnetism and geoelectricity, auroral phenomena, radio wave propagation, and plasma instabilities, are examples within the broad field of solar-terrestrial physics which emphasise the energy exchange between the solar wind, the magnetospheric and ionospheric plasmas, and the neutral gas. In the lower atmosphere, topics covered range from mesoscale to global scale dynamics, to atmospheric electricity, lightning and its effects, and to anthropogenic changes.