| Abstract Submission No. | ABS-3.1-0133 |
| Title of Abstract | Poleward Propagation of Ionospheric Anomalies Due to Volcanic Eruptions, Great Earthquakes, and Tsunamis |
| Authors | Dwijendra N. Pandey*, J. K. Catherine , Rajesh Rekhapalli, Vineet K. Gahalaut |
| Organisation | CSIR-National Geophysical Research Institute, Hyderabad, AcSIR |
| Address | Tectonic Geodesy Group CSIR-NGRI Hyderabad, Telangana, India Pincode: 500007 E-mail: dwijendrabhumet@gmail.com |
| Country | India |
| Presentation | Oral |
| Abstract | The ionosphere, a vital layer of Earth¿s atmosphere, is highly responsive to large-scale geophysical events such as volcanic eruptions, earthquakes, and tsunamis. In this study, we investigate ionospheric Total Electron Content (TEC) variations associated with the 2022 Hunga Tonga¿Hunga Ha¿apai volcanic eruption, two major earthquakes of magnitude greater than 8, and the 2011 Tohoku earthquake-induced tsunamis, with a particular focus on their poleward propagation characteristics. Using GNSS-TEC observations in conjunction with surface pressure data from meteorological sensors co-located with GPS receivers, we compare the intensity, propagation patterns, and underlying mechanisms of the ionospheric anomalies triggered by these events. Our analysis reveals that the Hunga Tonga eruption generated clear ionospheric disturbances, including multiple eruption signatures, which were detected in Antarctica with amplitudes up to 2 TECU. In contrast, no significant ionospheric anomalies were observed in the polar regions for either the great-magnitude earthquakes or the tsunami events, despite their large energy release. These findings suggest that seismo-tectonic events do not produce discernible ionospheric signatures in polar regions, whereas volcanic eruptions can generate strong and detectable disturbances at high latitudes. Furthermore, the long-period (0.28¿16.67 mHz) ionospheric oscillations recorded in Antarctica were found to closely follow the surface pressure perturbations, highlighting the strong coupling between atmospheric acoustic-gravity waves and ionospheric responses during volcanic activity. |
| Keywords | GNSS, TEC |