{"id":860895,"date":"2026-09-26T03:04:09","date_gmt":"2026-09-26T03:04:09","guid":{"rendered":"https:\/\/www.newsbeep.com\/us\/860895\/"},"modified":"2026-09-26T03:04:09","modified_gmt":"2026-09-26T03:04:09","slug":"tongas-2022-ultra-eruption-rewrote-the-rules-for-tsunamis-now-we-know-why","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/us\/860895\/","title":{"rendered":"Tonga’s 2022 \u2018Ultra\u2019 Eruption Rewrote the Rules for Tsunamis. Now We Know Why"},"content":{"rendered":"

Every single house on Mango Island was swept away<\/a> by the tsunami that radiated out when the submarine volcano Hunga-Tonga Hunga-Ha\u2019apai exploded off the coast of Tonga<\/a> in 2022. Only two buildings survived on nearby Fonoifua Island. Seven people were killed, and at least 19 more were injured\u2014with many cries for help lost as the eruption\u2019s undersea avalanche<\/a> severed telecommunications cables. It was reportedly<\/a> the largest and highest tsunami ever documented from an undersea volcanic blast.<\/p>\n

The event was so powerful that scientists unofficially debated creating a new \u201cultra\u201d category to describe it<\/a>. But despite Tonga\u2019s eruption being visible from space, very little data exists on submerged volcanoes like Hunga-Tonga Hunga-Ha\u2019apai due to these geological formations\u2019 deep-sea depths and the obvious challenges of doing science fathoms below sea level across far-flung patches of ocean. Nevertheless, a team led by marine geoscientist Marta Rib\u00f3 at the Auckland University of Technology (AUT) in New Zealand has managed to amass an impressive body of evidence for what made Tonga\u2019s 2022 blast so deadly.<\/p>\n

Using rare high-resolution sonar maps collected before and after the event, among other tools, Rib\u00f3 and her team have determined that Tonga\u2019s eruption created its unusually powerful tsunami by blasting out the geological formation above it into nearly one large, contiguous block. The heaving collapse of this mass back into the post-eruption depression, which geologists call a \u201ccaldera,\u201d helped launch volumes of ocean water at \u201cexceptional tsunami magnitude,\u201d the researchers wrote<\/a>, with waves as high as 131 feet (40 meters) as far away as 62 miles (100 kilometers) from the blast.<\/p>\n

\u201cSeafloor mapping before and after submarine [volcano] eruptions is\u202fvery rare,\u201d Rib\u00f3\u202f, the head of AUT\u2019s earth and life sciences department, said<\/a> in a statement. \u201cDespite their recognised threat, most submarine caldera volcanoes remain unmapped.\u201d<\/p>\n

A bigger splash <\/p>\n

Rib\u00f3\u202f and her collaborators paired these sonar maps, fortuitously taken before the eruptions in 2015 and 2016 and after in 2022, with water column observations to calculate the total volume displaced as the volcano\u2019s caldera caved in.<\/p>\n

In short, the collapse of Hunga-Tonga Hunga-Ha\u2019apai moved volcanic material equivalent to the\u202fvolume\u202fof 1,500 Great Pyramids or 89,000 modern aircraft carriers, according<\/a> to the National Oceanography Centre (NOC) in the U.K., which collaborated with AUT and other institutions on this new study. The caldera sank about 490 feet (150 meters) to roughly 2,790 feet (850 meters) below sea level, moving an estimated 2.1 cubic miles (8.9 cubic km) of sea floor and another 1.6 cubic miles (6.85 cubic km) of material from the volcano itself.<\/p>\n

\"TongaHigh-resolution sonar maps show the Tonga volcano\u2019s caldera pre-eruption (a) and post-eruption (b). The two bottom images display the geomorphology of the caldera and its surroundings. Credit: Rib\u00f3\u202f, et al. <\/p>\n

Crucially, these mass-balance equations leave out the obvious role that the thermal expansion of ocean water into high-pressure steam added to the eruption\u2019s power, as molten magma poured out around the edges of this volcano\u2019s island-sized caldera block. Vulcanologists call these types of steam-enhanced blasts Surtseyan<\/a> eruptions.<\/p>\n

After the hunt <\/p>\n

Isobel Yeo, a senior volcanologist at NOC who worked with Rib\u00f3 on the new study, hopes that their work inspires future expeditions to continue mapping submerged volcanic structures worldwide in a search for particularly dangerous candidates. In addition to their study on the Tonga volcano\u2019s collapse, published<\/a> this September in the journal Nature Geoscience, their work also produced a research briefing<\/a> in that same issue detailing the risks implied by their findings.<\/p>\n

\u201cBuilding repeat observations of these volcanoes is vital if we are to better understand the hazards they pose to coastal communities and critical seafloor infrastructure,\u201d Yeo said in a statement.<\/p>\n

Techniques like sub-bottom seismic profiling, for example, which uses sound waves to probe and characterize the rock layers hidden beneath the ocean floor, helped the team more accurately map the Tonga blast\u2019s volcanic debris. Rib\u00f3 believes that this kind of mapping work should be done for hundreds<\/a> more undersea volcanoes to properly assess their risk of caldera collapse.<\/p>\n

\u201cThere are at least 74 submarine volcanoes along the Tonga\u2013Kermadec\u202fArc, with 20 caldera complexes,\u201d she noted. \u201cYet, despite the hazards they pose, they are not well-understood as they remain unexplored.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"Every single house on Mango Island was swept away by the tsunami that radiated out when the submarine…\n","protected":false},"author":2,"featured_media":860896,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[32],"tags":[363356,79,14889,6737,106568],"class_list":["post-860895","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-geosciences","tag-science","tag-tsunamis","tag-volcanic-eruptions","tag-volcanology"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/860895","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/comments?post=860895"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/860895\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media\/860896"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media?parent=860895"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/categories?post=860895"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/tags?post=860895"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}