Tonga undersea volcano eruption released up to 18 megatons of energy

Scientists are starting to take the measure of the monster volcanic eruption that rocked the South Pacific kingdom of Tonga earlier this month.

The undersea volcano had been burbling since late December 2021, shaking the seas near Tonga with a series of outbursts. Things kicked into higher gear this month, with powerful blasts on Jan. 13 and Jan. 14 and then an even bigger eruption on Jan. 15 that sent ash and dust 25 miles (40 kilometers) into the Pacific sky.