Eventually, some volcanoes reach heights above the seafloor where lower pressure allows for explosive eruptions. These passive flows harden into rock and build up the height of the underwater mountain over millions of years.
Most volcanic islands originate from passive lava flows on the seafloor. “Typically, in the origin of most oceanic island volcanoes or submarine volcanoes, you need to melt the Earth’s mantle.” “The first thing you need is a supply of magma,” he says. Prior to joining the USGS, Mandeville focused his research on submarine volcanology, becoming an expert on the famous 1883 eruption of the island of Krakatoa in Indonesia.Īccording to Mandeville, there are two main factors that contribute to submarine volcanoes e ventually forming islands: the supply of magma and tectonic activity. He and his colleagues are responsible for monitoring all 169 active volcanoes-all terrestrial-in the United States. Most submarine eruptions do not disturb the ocean surface.Ĭharles Mandeville is the program coordinator for the Volcano Hazards Program of the United States Geological Survey ( USGS). The sheer weight of the water above them creates very high pressure, usually resulting in what are known as passive lava flows along the seafloor. For instance, it’s uncommon for submarine volcanoes to have explosive eruptions. Submarine volcanoes are exactly what they sound like-volcanoes located beneath the ocean’s surface.īecause they erupt into water instead of air, submarine volcanoes behave quite differently than terrestrial volcanoes. This is the first time scientists have seen underwater pyroclastic flows of this magnitude.From Hawaii to Indonesia to Iceland, hundreds of islands across the globe have been formed by submarine volcanoes. NIWA scientists also discovered currents of dense lava, volcanic ash and gases - called pyroclastic flows - travelled as far as 100 kilometres following the eruption. It was like a shotgun blast directly to the sky," he said. " the first we've ever seen to break through into the mesosphere. Project leader and marine geologist Kevin Mackay said the eruption reached record heights and the material it produced circulated the atmosphere for months. It caused 10 cubic kilometres - the equivalent of 2.6 million Olympic-sized swimming pools - of seafloor to be displaced and destroyed the ecosystems around the volcano.
NIWA found the volcano Hunga-Tonga Hunga-Ha'apai emitted the biggest atmospheric explosion recorded on Earth in more than 100 years. New Zealand's National Institute for Water and Atmospheric Research (NIWA) led the investigation. The eruption of an underwater Tongan volcano in January has been confirmed as the largest ever recorded. Photo: AFP / National Institute of Information and Communications
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