Magnetic Signatures of the January 15 2022 Hunga Tonga–Hunga Ha‘apai
Volcanic Eruption
Abstract
On January 15, 2022, at around 04:00 UTC, the submarine volcano Hunga
Tonga-Hunga Ha‘apai explosively erupted. We examine data from ten
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 minutes period, and ~1nT amplitudes, arrived at
~04:44 UTC. API’s signals are likely due to ionospheric
sources. 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 minutes
and 5-100+ minutes. 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.