Meteotsunamis triggered by the Hunga Tonga‑Hunga Ha’apai eruption in Livingston and Deception Islands, Antarctica: aliasing, generation place and importance of the water body geometry in determining their amplitude and time–frequency behaviour

Abstract

The eruption of the Hunga Tonga-Hunga Ha’apai volcano on 15 January 2022 triggered acoustic-gravity (Lamb) waves and meteotsunamis recorded all around the world oceans. These meteotsunamis are analysed on the basis of two tide gauge records in Antarctica, along with the atmospheric perturbation, which was obtained by using the atmospheric pressure records from nearby meteorological stations. The instruments are located on Deception and Livingston Islands (sea level and atmospheric pressure sensors). Three meteorological stations and three tide gauge stations along the Pacific Ocean were also used. The atmospheric leading front arrived at the meteorological stations ~ 4 h before the meteotsunami was recorded by the tide gauges. The passing of two atmospheric acoustic-gravity waves was clearly identified, one propagating eastwards and the other westwards. The meteotsunamis arriving at the study area showed amplitudes of up to 20 cm (Livingston Island) and 5 cm (Deception Island). A time–frequency analysis based on wavelet decomposition and the numerical computation of the meteotsunami refraction while approaching the stations revealed that the meteotsunami oscillations show quite different frequency content between the two stations. This may be explained in terms of the different amplification factors experienced by the meteotsunami while it interacts with the different geomorphological configurations of the corresponding water bodies. The records also evidence a marked difference in the meteotsunami arrival time at the two stations, which may be explained by the refraction effects on the meteotsunami fronts while they are approaching the two stations.