Why Was the Tonga Eruption So Massive? Scientists Have New Clues

How big was the January eruption of the volcano? Four months of intensive science has made a difference. You could point to the booms that interrupted the night in Alaska. A rare form of acoustic wave that hopped over continents and stirred up the seas may have caused the Caribbean's tsunamis. NASA scientists said earlier this month that the weather changed in space, with winds from the blast increasing to 450 miles per hour as they left the atmosphere. The flow of electrons around the equator had previously been disrupted by solar wind.

Which is why, when researchers started looking at the ocean floor, they expected to find a bad landscape. It would be covered in debris after the blast. The explosion was caused by hot, gaseous magma meeting cold, salty sea water. How did those two ingredients come together? Some of the leading theories centered on the idea of a collapse of the volcano's slopes. That would help explain the deaths of three people in the Tongan islands. A huge shift in submarine rock means a huge amount of water is displaced.

A group of scientists from New Zealand observed something different. The terrain has changed and is now covered with at least enough ash to fill 3 million Olympic swimming pools. It isn't all that different. The slopes of the underwater volcano are the same as they were before the eruption. Some of the features are still teeming with life, with starfish and corals clinging to rocky seamounts.

The depression left behind when the volcano blew was just right above the caldera. The risk of large explosions was not the reason that the large research vessel did not sail there. They suspected total destruction. The islands that had risen out of the sea were torn asunder by the blast.

The NIWA team released their findings a day after a second group of researchers helped fill in the map. The team went out over the caldera with a similar set of acoustic instruments, using a smaller ship that was less at risk from the bubbles. It was a hole. The gash is 4 kilometers wide and 850 meters deep, hemmed in by the volcano's original slopes.

Scientists are using the two sets of observations to reconstruct a massive underwater explosion. The image shows that Hunga blew up. As the caldera broke apart in the early stages of the eruption, there was a flood of water that met deep regions of magma, causing a chain reaction. There are more eruptions of seawater, magma, and explosions.