Magnetic Signatures of the 15 January 2022 Hunga Tonga–Hunga Ha'apai Volcanic Eruption

Abstract

On 15 January 2022, at around 04:00 UTC, the submarine volcano Hunga Tonga-Hunga Ha'apai explosively erupted. We examine data from 10 Pacific Ocean geomagnetic observatories and process the data using both high pass filters and cross-wavelet analyses to enable evaluating the time-frequency characteristics of the magnetic signals across the Pacific region. At the Western Samoa observatory (API), magnetic signals of 3–8 min period, and visible in both vertical and horizontal fields, arrived at ∼04:44 UTC. The observatories at Chichijima Island (CBI) and Easter Island (IPM) both had local magnetic signatures concurrent with the eruption's water wave arrival and period ranges from, respectively, 13–93 and 5–100+ min. At CBI and IPM, the magnetic signal may be due to both the eruption's tsunami water wave and atmospheric/ionospheric sources. Our results suggest that the magnetic signatures from the eruption are identifiable and may be further separated in future studies.