On Monday, at 2:11 p.m. local time, an explosive eruption rocked White Island, a small volcanic isle in New Zealand’s Bay of Plenty. A series of violent blasts rang out, flinging ash 12,000 feet into the sky and showering the volcano’s floor with hot debris, before everything fell silent a handful of minutes later.
It quickly became apparent that lives were lost. A number of tourists were on the island at the time, several of whom were right next to the volcano’s active vent. At the time of writing, five deaths have been officially recorded, with several more people still unaccounted for. Recent reconnaissance flights over the island, also known by its Māori name Whakaari, have found no signs of life.
For this sort of volcanic paroxysm, “this was probably the actual worst-case scenario,” says Shane Cronin, a volcanologist and Earth scientist at the University of Auckland.
Understandably, this explosion took many by surprise. But for this volcano, and for the type of eruption style involved, it was nothing out of the ordinary: Similar eruptions, though not everyday occurrences, have happened at many volcanoes all over the world, and they will continue to appear without much warning. (Find out the most dangerous volcanoes in the U.S., according to geologists.)
“This is a case of people being in the wrong place at the wrong time,” Janine Krippner, a volcanologist at the Smithsonian Institution’s Global Volcanism Program. “It’s horrible when it happens, but it will continue to happen over and over again.”
So why was the eruption at Whakaari/White Island so unpredictable and deadly? Let’s look at the facts.
Invisible warning signs
Whakaari/White Island is the summit of a complex submarine volcano. According to the Smithsonian Institution’s Global Volcanism Program, it is highly ebullient, engaging in a variety of eruption styles. Many feature moderate explosions.
As a result of its hyperactivity, and the frequency with which tourists visit, Whakaari/White Island is heavily monitored. Scientists were keeping a close eye on it to try and spot any behaviors that could potentially indicate the volcano was gearing up for something explosive.
Volcanologists with GNS Science, a New Zealand-based consulting group, spotted some localized surface deformation a few weeks earlier, says Geoff Kilgour, a scientist with the group. Deformation can be indicative of subsurface pressure changes caused by moving superheated liquids, gases, or magma. But in this case, the activity didn’t indicate that any major build-up of pressure was happening.
Still, monitoring efforts and reports from tourist companies also picked up some geyser-like convulsions at the time, along with an uptick in gas emissions and seismic