NASA scientists estimate Tonga blast at 10 megatons

PO1 William "Chip" Nagel
"NASA researchers have an estimate of the power of a massive volcanic eruption that took place on Saturday near the island nation of Tonga.

"We come up with a number that's around 10 megatons of TNT equivalent," James Garvin, the chief scientist at NASA's Goddard Space Flight Center, told NPR.

That means the explosive force was more than 500 times as powerful as the nuclear bomb dropped on Hiroshima, Japan, at the end of World War II.

The blast was heard as far away as Alaska and was probably one of the loudest events to occur on Earth in over a century, according to Michael Poland, a geophysicist with the U.S. Geological Survey.

"This might be the loudest eruption since [the eruption of the Indonesian volcano] Krakatau in 1883," Poland says. That massive 19th-century eruption killed thousands and released so much ash that it cast much of the region into darkness.

In the case of this latest event, Garvin says that he believes the worst may be over — at least for now.

"If the past precedent for volcanic eruptions in this kind of setting has any meaning at all," he added, "then we won't have another one of these explosions for a while."

Even three days after the blast, Tonga remains largely cut off from the world. Undersea communications cables appear to have been cut, and the airport is covered in ash, preventing relief flights from arriving at the capital city of Nuku'alofa.

Reconnaissance flights by the government of New Zealand showed ash had blanketed houses and many other structures. New Zealand's Foreign Ministry reported that two people had been confirmed killed and that a tsunami had inundated the western coast of the main island of Tongatapu, causing major damage. Wire reports cite the government of Tonga claiming one additional death and even more damage on outlying islands, including Mango island, where all homes have been destroyed."...