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Spectral characteristics of ionospheric disturbances over the Southwestern Pacific from the January 15, 2022 Tonga eruption and tsunami
  • Jessica N Ghent,
  • Brendan W Crowell
Jessica N Ghent
University of Washington, University of Washington

Corresponding Author:[email protected]

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Brendan W Crowell
University of Washington, University of Washington
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Abstract

On January 15, 2022, Tonga’s Hunga Tonga-Hunga Ha’apai (HTHH) volcano violently erupted, generating a tsunami that killed three people. Acoustic-gravity waves propagated by the eruption and tsunami caused global complex ionospheric disturbances. In this paper, we study the nature of these perturbations from Global Navigation Satellite System observables over the southwestern Pacific. After processing data from 818 ground stations, we detect supersonic acoustic waves, Lamb waves, and tsunamis, with filtered magnitudes between 1 and 7 Total Electron Content units. Phase arrivals appear superpositioned up to ~1000 km from HTHH and are distinct by ~2200 km. Within ~2200 km, signals have an initial low-frequency pulse that transitions to higher frequencies. We note the presence of a faster perturbation generated one hour post-eruption which crosses the tsunami disturbance ~3000 km from HTHH, potentially contributing to premature land arrivals. Lastly, the arrival of tsunami-generated disturbances coincides with deep-ocean observations.