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Tonga volcanic eruption ‘hundreds of times’ more powerful than Hiroshima atomic bomb, NASA says

The powerful volcanic eruption in Tonga this month, which triggered a tsunami, was hundreds of times more powerful than the atomic bomb dropped by the United States on Hiroshima during World War II, according to Nasa.

“This is a preliminary estimate, but we believe the amount of energy released by the eruption was equivalent to somewhere between 4 and 18 megatons of TNT,” NASA scientist Jim Garvin said in a new blog post.

In comparison, they said Mount St Helens in the United States exploded in 1980 with 24 megatons and Krakatoa erupted in 1883 with 200 megatons of energy.

“This number is based on the amount removed, the strength of the rock and the height of the eruption cloud blown into the atmosphere at different speeds,” added Dr. Garvin, chief scientist at NASA’s Goddard Space Flight Center. .

NASA scientists have used a combination of satellite observations and surface geophysical surveys to track this rapidly changing part of the Earth.

Before the eruption, they said the Hunga Tonga-Hunga Ha’apai volcanic island was made up of two separate islands that were joined by the formation of new land in 2015.

However, after the eruption they say all new land “disappeared”, along with large chunks of the two older islands.

Nasa researchers have been studying this part of the planet for the past six years to understand how the young terrain was eroding due to churning waves and the occasional blast from tropical cyclones.

They also assessed how different flora and fauna, including shrubs, grasses, insects and birds, had moved from the lush ecosystems of Hunga Tonga and Hunga Ha’apai and colonized the more arid landscapes of the new land. .

While at the start of 2022 volcanic activity seemed “pretty typical”, with intermittent small bursts of ash, steam and other volcanic gases, they quickly took a turn and began to reshape the landscape and expand the island by adding new cinder and tuff deposits to the growing volcanic cone.

“In early January, our data showed the island had expanded by about 60% compared to before December activity began,” Dr Garvin said.

“The whole island had been completely covered with a tenth of a cubic kilometer of new ash. This was all pretty normal, expected and very exciting behavior for our team,” he added.

However, in mid-January, researchers said an “unusually powerful set of explosions” sent ash into the stratosphere.

These January 15 explosions launched material up to 40 km a.s.l., “and possibly as much as 50 km, blanketing nearby islands in ash and setting off destructive tsunami waves,” they noted.

Three people, including two Tongan nationals and a British woman, have been confirmed killed by the eruption and tsunami which destroyed hundreds of homes and cut communications on several islands.

Tonga’s government said on Monday that more than 80% of the country’s 105,000 people have been affected by the ashfall and tsunami.

Politicians and aid agencies have warned there could be potential food shortages as crops across Tonga have been ruined by the ash.

Non-contact flights and vessels carrying relief materials including fresh water have been arriving in Tonga since last week in an effort to support the population and also as a precaution to prevent infection with the novel coronavirus.


The Independent Gt

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