White Island Disaster: Story Behind the Horrifying Volcanic Eruption That Killed 20 Tourists

At 2:11 p.m. on Monday, White Island, a tiny volcanic isle in New Zealand's Bay of Plenty, was shaken by an enormous eruption around 10 a.m. local time.

A succession of powerful explosions erupted, hurling ash 12,000 feet into the sky and showering the volcano's floor with scorching material before all was silenced a few minutes later.

It was clear right once that lives had been lost. At the time, many visitors were on the island, some of whom were standing quite near to the volcano's active vent.

"This was probably the true worst-case scenario" for this type of volcanic eruption, says Shane Cronin, a volcanologist and Earth scientist at the University of Auckland.

The explosion, understandably, caught many people off guard. But it was nothing unusual for this volcano and the sort of eruption style involved: similar eruptions have occurred at numerous volcanoes throughout the world, and they will continue to do so without notice.

An Unexpected Eruption

So, why was Whakaari/White Island's eruption so unexpected and deadly?

The top of Whakaari/White Island is a complicated undersea volcano. According to the Smithsonian Institution's Global Volcanism Program, it is very exuberant, erupting in a variety of types. Many of the explosions are modest.

Hyperactivity

Whakaari/White Island is constantly watched due to its hyperactivity and the regularity with which tourists visit. Scientists were keeping a careful eye on it in the hopes of spotting any signs that the volcano was preparing for a catastrophic eruption.

GNS Science, a New Zealand-based consulting firm, observed some localized surface deformation a few weeks ago, according to Geoff Kilgour, a scientist with the firm. Subsurface pressure changes generated by flowing superheated liquids, gases, or magma can cause deformation. However, the activity did not imply a significant increase in pressure in this circumstance.

Nonetheless, certain geyser-like convulsions and an increase in gas emissions and seismic rumblings were detected by monitoring efforts and reports from tourist firms at the time. As a result, the volcano's warning status was raised. An increase in the alert level does not always guarantee that an eruption will occur, and in many circumstances, no eruption will occur. This time, however, there was a fatal exception.

This can cause gases to become trapped beneath the surface, where they accumulate and heat up, generating a pocket of superheated components similar to a pressure cooker. The boiling water frequently tries to turn into steam, but it stays a liquid due to the high pressure.

This implies that any fracture in this geologic pressure cooker can result in a violent, rapid decompression. Liquid water turns into steam in a heartbeat, expanding its volume 1,700 times. The expanding force is powerful enough to break rocks and leave scars on the earth's surface.

When the pressure at the vent is released, a decompression wave is launched into the volcano's throat, colliding with more pressured water. A steam-based eruption can change into a magma-driven explosion when the shockwave reaches the magma.

Deadly Steam

According to Cronin, if you stand too close to the vent, even a steam explosion may kill you. However, the flying boulders, moist debris jets, and burning air may be deadly.

And everything occurs so quickly that no one has time to respond. The majority of this eruption was a series of impulsive bursts, each lasting only a few seconds. According to Kilgour, the whole incident was over in just two minutes. Due to the limited size of Whakaari/White Island, the situation is particularly risky.

"On White Island, there aren't many places you can go without being near the vent," says Loc Vanderkluysen, a volcanologist at Drexel University.

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