The White Island Volcano in New Zealand – that erupted monday with a huge explosion of ash and scorching steam, killing at least five people – it's one of New Zealand's most active volcanoes.
The volcano erupted as tourists were exploring the moon-like surface.
"Our monitoring data shows that there was a short-lived eruption that generated an ash cloud at (estimated) 12,000 feet above the opening," according to GeoNet, which monitors volcanoes and earthquakes in New Zealand.
In addition to the ash plume, the hot flying rocks probably exploded out of the crater, covering the area, Smithsonian Institution volcanologist Janine Krippner told USA TODAY.
The eruption itself was within the normal range of volcano activity, she said; is that this time "people were in the wrong place at the wrong time".
"Whakaari," as it is known in the Maori language, is New Zealand's most active cone volcano, built by continuous volcanic activity over the last 150,000 years, GeoNet said.
"About 70% of the volcano is at the bottom of the sea, making this huge volcanic structure the largest in New Zealand," according to GeoNet.
Conical volcanoes They are also known as stratovolcanoes or composite volcanoes. They are one of the three main types of volcanoes, along with shield and dome.
GeoNet raised its warning level on White Island on November 18 from 1 to 2 on a scale where 5 represents a major eruption, noting an increase in sulfur dioxide gas originating from magma deep within the volcano. He also said that volcanic tremors increased from weak to moderate strength.
The most recent deaths from White Island volcano were in 1914, when 12 people died on the island when it was being mined by sulfur, GeoNet said. Part of a crater wall collapsed and a landslide destroyed the miners' village and the mine itself.
There was also a short eruption in April 2016.
Activity seems to have slowed since the eruption, GeoNet said. "There is still significant uncertainty about future changes, but there are currently no signs of escalation."
Volcanic activity on the island reached an alert level of four in five immediately after the eruption, but has since been reduced to three.
"In the scheme of things, for volcanic eruptions, it's not big," said Ken Gledhill of GeoNet. "But if you were close to that, it wouldn't be good."
Krippner agreed with this assessment, saying that as volcanic eruptions occur, this was "small. But even the smallest eruption can be catastrophic for those close to it."
Contribution: Associated Press