A New Zealand team of marine geologists studying an underwater volcano that erupted in the Tongan archipelago in the South Pacific on January 15 has found it to be the “largest on record” using modern equipment.
The Hunga Tonga-Hunga Ha’apai volcano, which unleashed a tsunami and sonic boom that twice orbited the globe, was captured in dramatic satellite imagery that showed a huge plume of ash and steam being hurled into the atmosphere.
A team of oceanographers, scientists and marine geologists led by the New Zealand National Institute for Water and Atmospheric Research (NIWA) have carried out the “most comprehensive survey yet” with the assistance of a remotely piloted robotic boat operated by Sea-Kit International in the UK. in the underwater volcano of Tonga. They discovered that almost 10 cubic kilometers of seafloor had been shifted – the equivalent of 2.6 million Olympic-size swimming pools.
“The eruption reached record highs and was the first we’ve ever seen to penetrate the mesosphere,” said Kevin Mackay, NWA marine geologist. “It was like a shotgun blast straight into the sky.”
“While this eruption was large, one of the largest since Krakatoa in 1883, there have been others of similar magnitude since then that didn’t behave that way. The difference here is that it’s an underwater volcano, which is also one of the reasons we got such big tsunami waves,” Mackay added.
The team of scientists also deciphered new information about the volcano’s underwater pyroclastic flows — a mixture of hot, dense volcanic ash, lava fragments and gas ejected from the volcano — by examining sedimentary debris found 80 km away.
“The sheer force of the currents is amazing – we saw deposits in valleys behind the volcano where the international cable lies, meaning they had enough force to flow up giant ridges and then back down,” said Dr. Emily Lane, senior NIWA scientist.
The volcano was also found to have injected a huge cloud of water vapor into the Earth’s stratosphere. According to NASA, only the 2015 Calbuco eruption in Chile and the 2008 Kasatochi Island eruption in Alaska released significant amounts of high-altitude water vapor.
“We’ve never seen anything like it,” Luis Millán, an atmospheric scientist at NASA’s Jet Propulsion Laboratory, said in a statement in August.
It was also found that the crater of the Hunga Tonga-Hunga Ha’apai volcano is 700 meters deeper than before the eruption.