What you need to know about the Tonga volcano and the Pacific Ring of Fire

The Hunga Tonga-Hunga Ha’apai volcano, poking 300 feet out of the ocean, is seen smoking Jan. 7. It erupted Jan. 15, sending tsunami waves around the world. (Planet Labs Pbc/AP)

As Tonga reels from the powerful undersea volcanic eruption that sent a tsunami crashing into the Pacific island nation — and coated its communities in a blanket of ash — experts are working to determine the broader impact of the massive explosion.

The blast, which sent a plume of ash and gas as high as 19 miles into the air, may have been the world’s largest eruption in 30 years, scientists say.

Videos and aerial images of the Tongan archipelago since the explosion have offered a window into the devastation, with entire communities buried in ash or severely damaged as a result of the tsunami.

Aid arrives in Tonga after ash-strewn airport runway is cleared with ‘human power’

According to the United Nations and a statement from Tonga’s government, at least three people were killed, nearly all communication lines were severed and volcanic debris may have contaminated the islands’ drinking water.

Aid first managed to reach the island Thursday after residents managed to clear a runway by hand.

The disaster may have just been a warm-up: The Hunga Tonga-Hunga Ha’apai volcano, which has erupted several times in recent years, is part of the Pacific Ring of Fire, home to some of the world’s most active volcanoes.

Here’s what you need to know about the eruption, volcanic tsunamis and the Ring of Fire.

‘Major disaster’: Tonga faces weeks cut off as volcanic activity imperils operation to repair fiber-optic cable

Tonga’s massive underwater volcanic eruption Jan. 15 could deliver long-lasting damage to coral reefs, erode coastlines and disrupt fisheries, scientists say. (Video: Reuters)