A new report has revealed Tonga's underwater volcano disaster triggered waves up to 90 metres high.
The University of Miami and the Khaled bin Sultan Living Oceans Foundation report states the eruption of the Hunga Tonga-Hunga Ha'apai Volcano last year was more powerful than the largest US nuclear test.
It involved the collaboration of scientists from numerous agencies including NASA, NIWA, and the Tonga Geological Service.
One of the co-authors, Auckland University Professor Shane Cronin, said the findings increasingly show what a monumental event the eruption was.
"Everything we knew about the explosive power of submarine volcanoes has been completely thrown out the window," he said.
Professor Cronin was one of the first academics to visit the post-eruption site of the Hunga Tonga-Hunga Ha'apai volcano.
"We realise from this eruption that there's a whole type of volcanic activity of submarine volcanoes that we never imagined could happen.
"It's really opened up our eyes to another type of volcano and now that we've seen this example we can now start to better understand other submarine volcanoes."
The record-breaking volcano was 500 times more powerful than the bomb that hit Hiroshima, generating a mushroom cloud that penetrated the atmosphere that was visible from space.
It was largest eruption since the Krakatoa eruption Indonesia a century ago, generating one of the largest sonic booms ever recorded.
"We went around measuring all the places where the tsunami waves ran up using drones and survey equipment," said Professor Cronin.
"The waves went right up and above two islands near the caldera, so the waves must have been at least 85 to 90 metres to have gone above those islands.
"The wave rises up but it always losses a lot of energy and it hit a very extensive area of reef and shallow water, so by the time it reached Nuku'alofa, the wave had dissipated.
"It's a blessing for our knowledge."