An underwater volcano erupted in Tonga on Saturday, triggering tsunami warnings across the world including in Australia.

Two deaths have been reported. But with all phone lines and internet disconnected, the damage to Tonga and surrounding Pacific islands is yet to be assessed.

The first satellite photos of the aftermath, as well as aerial shots from the first surveillance flights, were released on Tuesday, showing some of the damage.

Experts are warning more eruptions could be on the way, but it’s hard to know what it’s like on the ground, or what’s yet to come.

Here’s what we know so far.

The situation in Tonga

New Zealand has reported that parts of the Tongan capital Nuku’alofa suffered “significant” damage, and two deaths have been reported as of January 18. One has been identified by family as Angela Glover, a British charity worker living in Tonga. Tongan authorities have not yet confirmed either death.

The first images from by the United Nations Satellite Centre (UNOSAT) as well as New Zealand Defence flights have been released, showing evidence of tsunami damage, flooding and land blanketed in volcano ash.

UNOSAT said it surveilled 104 structures and 41 were identified as damaged, as well as roads and trees on several islands. 

tonga-volcano
Image source: UNOSAT
First Photos Of Tonga Following Volcano Eruption Show Tsunami Damage & Islands Blanketed In Ash
Image source: UNOSAT

The Royal New Zealand Air Force P-3K2 Orion took a reconnaissance flight on January 17 to assess the damage from the air and releases images of ash-covered buildings, trees and beaches on the Tongan island of Nomuka.

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Image source: NZDF
tonga-volcano
Image source: NZDF

Aid agencies said the ash and smoke had prompted authorities to ask residents to wear masks and drink bottled water.

But with communication still yet to be restored, our picture of what it’s like on the ground is still developing.

Internet was cut off around 6pm on Saturday, three hours after the eruption.

Tonga gets its internet via an undersea cable from Fiji, which has likely been disturbed or damaged.

At a press conference on Monday morning Australian Foreign Minister Marise Payne said Australia was working to provide assistance to restore communications.

“If this is the case that there is damage to the submarine cable, then that is obviously a significant challenge for repair work,” she said.

“We’ll work closely with all of our partners to provide whatever assistance we can, including the commercial providers of the submarine cable and also to see what else is there to support in communications support.”

Australia sent a P-8 plane to assess the damage following the natural disaster on Saturday.

It arrived in Tonga on Monday morning, with crews still checking for damage to critical infrastructure.

New Zealand Prime Minister Jacinda Ardern has pledged an initial support package of $NZ500,000, which she said was a “starting figure”.

The explosion

Activity at the underwater volcano Hunga Tonga-Hunga Ha’apai began in late December with moderate eruptions. It had been active for the last 15 years and had previously erupted in 2009, 1988, 1937 and 1912.

At 3.10pm AEDT on Saturday, it erupted on a much larger scale. The explosion sent a plume of ash 20km into the air and 130km wide from a volcanic vent just above sea level.

The blast could be heard by residents of Fiji,  New Zealand and even as far away as Alaska. In Fiji, 1,000km from the crater, it sounded like a loud thunder clap.

The force of the eruption has not yet been accurately measured, but it has been estimated it was equivalent to 1000 Hiroshima bombs.

The US Geological Survey estimated the eruption caused the equivalent of a magnitude-5.8 earthquake.

The eruption generated a tsunami that early videos have shown to cause damage in Tonga.

Some of the country’s 105,000 residents shared footage of the ash cloud, as well as large waves washing up onto shore.

Satellites captured footage of the explosion from space, showing the monstrous blast and the ripple effect in the atmosphere. 

Effects around the world

The wave swell caused by the eruption has travelled across the Pacific Ocean, resulting in tsunami warnings and damage to boats in New Zealand, Australia and the US.

In California, a tsumani surge washed up onto shore and flooded a carpark.

On Saturday, Bondi Beach was evacuated at 10.30pm after the Bureau of Meteorology said it had detected large waves and changes in atmospheric pressure, which can result in changed weather conditions.

NSW SES closed beaches across the state, but the tsunami alerts for waters off Australia’s east coast have since been cancelled.

NSW SES said conditions would remain hazardous today and that everyone should avoid the water until there was more information.

What can we expect in the eruption aftermath?

Grace Legge, a senior meteorologist for Australia’s Bureau of Meteorology warned that we’re “not out of the woods,” as per the ABC.

She said underwater eruptions were much harder to predict than atmospheric weather patterns or earthquakes, and that volcanic activity could continue for weeks or months.

We can also expect to see pumice stone washing up on Australia’s east coast in the months ahead.

Pumice is volcanic rock that’s full of holes so can float.

We’ll be updating this story as more news breaks and communications from Tonga are restored. For now, if you live on the east coast, follow SES and surf lifesaving advice and stay away from the beach.