The Hunga-Tonga Hunga Ha'apai Eruption of January 15, 2022: Seismological Perspectives
Fred Pollitz
USGS ESC Moffett Field
- Date & Time
- Location
- Microsoft Teams meeting only
- Summary
The 15 January, 2022 eruption of Hunga Tonga Hunga Ha’apia is the largest since the 1991 Mount Pinatubo eruption. It produced a local tsunami with up to 15 m height and inundation of 500m; a plume that eventually reached 58 km height; globally recorded infrasound waves through Earth’s atmosphere; acoustic-gravity standing waves at two dominant resonant frequencies; worldwide sea waves driven in part by the atmospheric Lamb pulse. It produced globally observed seismic signals from coupling of the different atmospheric waves with the solid earth, as well as direct signals from the volcano due to the reaction force. We explore different seismological approaches to deriving the source time function of the reaction force, which is well characterized as a sequence of Impulsive vertical forcing that produced seismic wave energy in multiple packets for 5000 s after the initial Surtseyan eruption, with a late burst around 15000 s. The seismological results are consistent with the generation of the eruptive plume that expanded rapidly for the first 90 minutes, implying average forces of 10^12 N over this time but reaching magnitudes as high as 2x10^13 during the eruption subevents.
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