Global Tonga tsunami explained by a fast-moving atmospheric source

Abstract

Volcanoes can produce tsunamis by means of earthquakes, caldera and flank collapses, pyroclastic flows or underwater explosions1–4. These mechanisms rarely displace enough water to trigger transoceanic tsunamis. Violent volcanic explosions, however, can cause global tsunamis1,5 by triggering acoustic-gravity waves6–8 that excite the atmosphere–ocean interface. The colossal eruption of the Hunga Tonga–Hunga Ha’apai volcano and ensuing tsunami is the first global volcano-triggered tsunami recorded by modern, worldwide dense instrumentation, thus providing a unique opportunity to investigate the role of air–water-coupling processes in tsunami generation and propagation. Here we use sea-level, atmospheric and satellite data from across the globe, along with numerical and analytical models, to demonstrate that this tsunami was driven by a constantly moving source in which the acoustic-gravity waves radiating from the eruption excite the ocean and transfer energy into it by means of resonance. A direct correlation between the tsunami and the acoustic-gravity waves’ arrival times confirms that these phenomena are closely linked. Our models also show that the unusually fast travel times and long duration of the tsunami, as well as its global reach, are consistent with an air–water-coupled source. This coupling mechanism has clear hazard implications, as it leads to higher waves along land masses that rise abruptly from long stretches of deep ocean waters.

A Multi-Parametric and Multi-Layer Study to Investigate the Largest 2022 Hunga Tonga–Hunga Ha’apai Eruptions

“…The study of the tsunami triggered by the volcano continued with [25] who well modeled the air-sea-coupled tsunami with an atmospheric pressure pulse, and finally ref. [26] affirmed that the tsunami was driven by a constantly moving source in which the acoustic-gravity waves radiating from the eruption excite the ocean and transfer energy into it via resonance.…”

Tsunami Runup and Inundation in Tonga from the January 2022 Eruption of Hunga Volcano

“…1). Hunga is often referred to by the names of two small islands Hunga-Tonga and Hunga Ha'apai that are located on the submarine caldera's northern rim (Cronin et al, 2017), During the first 45 min of this eruption, a massive atmospheric pressure wave and a series of tsunamis were generated and observed around the world (Carvajal et al, 2022;Imamura et al, 2022;Lynett et al, 2022;Omira et al, 2022). This event highlights an unexpectedly great hazard from volcanic tsunami worldwide (Paris, 2015;Whelan & Kelletat, 2003), which in Tonga's case Supplementary Information The online version contains supplementary material available at https://doi.org/10.1007/s00024-022-03215-5.…”

Eruption chronology of the December 2021 to January 2022 Hunga Tonga-Hunga Ha’apai eruption sequence

“…O n 15 January 2022, between 04:00-04:10 UTC, the shallow water Hunga Tonga-Hunga Ha'apai (referred as, "HTHH") (175.38°W, 20.57°S) volcano, produced one of the past century's most energetic submarine eruptions. The ashfall and tsunamis produced by the eruption severely affected the Kingdom of Tonga and surrounding regions [1][2][3][4][5][6] . Lamb waves produced by the HTHH eruption circled multiple times around the globe 5 and the highest plume reached ~55-58 km 7,8 .…”

“…Here we assess the maximum heights and volume fluxes of the umbrella clouds from these recent eruptive phases of the HTHH (specifically, the explosive eruptions on 19 Dec 2021, 13 Jan 2022, and 15 Jan 2022). We focus on the umbrella cloud because it contains a significant fraction of volcanic material hours after eruption onset 11,12 , is essential for understanding the physical processes associated with the HTHH explosive eruptions, and its behavior is likely correlatable with other data sets (e.g., seismic, atmospheric, infrasound, hydroacoustic, lightning 1,5,6 ). We acknowledge that plumes often overshoot the umbrella cloud height and thus the umbrella height is not the maximum plume height.…”