Tonga volcano eruption: Locals still in disbelief one year on from devastating eruption, tsunami

It's been one year since the volcanic eruption in Tonga that reached the edge of space and sent a 20-metre-high tsunami barreling across the Kingdom's tiny islands at 500 kilometres per hour.

It was the most violent explosion on Earth in 140 years, but incredibly only three people were killed.

Now, a Newshub crew became the first news crew in the world to visit the tip of the submarine volcano since it erupted.

On the horizon, what's left of the mouth of the Hunga Tonga Hunga Ha'apai volcano appears as two chunks of reddish rock.

A year after it was blasted into oblivion, acting Prime Minister Samiu Vaipulu is still in disbelief about the eruption.

"We think, 'How on Earth are we still here?'" he said.

The eruption triggered a tsunami and brought devastation to Tonga. In one instance, a 10,000-litre tank was tossed on its side, serving as a reminder of the powerful force that swept through.

Such memories were still raw at a ceremony celebrating the first responders. A police boss described the sonic booms that signalled what was to come.

"Then it comes with the shockwaves, it's shaking everything, and I thought to myself, 'How big is that tsunami coming? Over 10m, 15m, 20m?" said Kepueli Taumoepeau, Chief Superintendent of Police.

New Zealand scientists have now confirmed they were 20 metres high. Local skipper Mohammed Razak has witnessed the astounding change to the islands on the volcano's rim. His GPS reveals countless fishing trips there, including one just two weeks before the eruption.

"We fished around, we had a lot of sulphur smelling, but we fished all night and we went back in the morning," Razak said.

His photos show the islands how they were before the eruption.

"All the green has gone. It has coconuts, guavas, chillis. Everything was on this island."

Scientists said they had no idea submarine volcanoes like Tonga's could erupt this violently.

"It's never been seen before, through modern instrumentation, ever, and so it just defies expectations, it just defies belief. It really was a tremendous, unique event," said Kevin Mackay, NIWA marine geologist.

On the western side of the main island, resort owner Peseti Ma'afu told Newshub the morning after the tsunami, the entire resort has disappeared.

The tsunami wave came through like a bulldozer, destroying the reef and leaving behind a seawater swimming pool as the only sign that it was once a resort.

They continue to wait for government help to rebuild.

"Tourists don't come now because we are not ready, so they are filling up Rarotonga, Samoa and Fiji," Ma'afu said.

Seabirds have now returned to Hunga Tonga as nature moves on, but there is a powerful message left behind.

"Mother Nature can do anything, any time, any place," Vailea said.

One year on, life has moved on as well. It is their faith that keeps the smiles on Peseti and his wife Tala's faces.

"We still have our self, our experience, our brains, so we can do it again."

Because Tongans know their home is always vulnerable to forces far beyond their control.