PBS News Hour

Australia and New Zealand sent out surveillance flights to Tonga today in the wake of an enormous undersea volcano eruption on Saturday. Communication with the South Pacific island chain remains largely cut off, but there is word of significant damage. Nick Schifrin has our report.

NICK SCHIFRIN

A blast so massive, it was seen from space. Satellite imagery caught the explosion and a ball of ash billowing above and beyond the Tongan Islands. Before the blast, thick plumes filled the sky, shooting up 12 miles above sea level. On Tonga, the tsunami arrived quickly. Communications are almost completely down, and the death toll is unknown, but one confirmed dead, Briton Angela Glover, who ran a rescue dog charity. Her brother Nick spoke in the U.K. NICK ELEINI,

Brother of Angela Glover

I haven't got the words in my vocabulary to even describe how we're feeling at the moment.

NICK SCHIFRIN

The explosion caused waves around the world. In Pacifica, California, harbors flooded. In Japan's Sakihama Port, fishermen looked on as their boats sank. And, in Peru, coastal areas flooded, and two women drowned after waves swept them away. In total, around the world, the explosion affected at least 11 countries and territories. ED VENZKE,

Smithsonian Global Volcanism Program

It's a rare explosion that reaches the stratosphere. And that's what got everyone's attention.

NICK SCHIFRIN

Ed Venzke is a senior researcher with the Smithsonian's Global Volcanism Program. He says the eruption comes from a chamber of magma forcing itself through rock.

ED VENZKE

Just like a bottle of soda, the gas that's contained in that liquid magma starts to expand. And so it reaches the surface right with the magma and start an eruption. And it's when that hot magma hits the water, the water expands and creates its own explosion.

NICK SCHIFRIN

A volcanic explosion that's believed to be the largest in three decades. For the "PBS NewsHour," I'm Nick Schifrin.