There is no such thing as a safe active volcano. We're seeing that truth play out on New Zealand's volcanic Whakaari / White Island, where at least five people were killed, 31 injured, and eight missing after an eruption on Monday.
I won't say the eruption was unexpected. The privately-owned volcano, a popular tourist destination, is the country's most active, with its latest previous eruption occurring in 2016. Even when it's not erupting, it's continually venting gas and steam - in fact, European explorer James Cook named it White Island because of those dense white steam plumes, and the Maori likely named it "that which can be made visible (Whakaari)" due to those clouds. It has extensive active fumaroles and hydrothermal features like mudpots. And it had all of the hazards associated with such activity.
It was in a state of heightened unrest before the afternoon eruption occurred. It certainly took tourists by surprise, because we have no way of determining exactly if or when a volcano will erupt, or how strong that eruption will be. Every tour company that ferried passengers to that volcano was rolling dice. They tried to increase the odds in their favor by limiting the size of the tour groups, monitoring alerts, and providing basic safety equipment such as gas masks and hardhats. But even with precautions, it was only a matter of time before they rolled snake eyes.
Some of the passengers may have completely known and understood the risks, and decided they were worth it for the chance to walk in the crater of a living volcano. I'll be honest: I would be one of them. There is absolutely nothing wrong with deciding that the reasonably small risk of death or serious injury is worth the knowledge and experience to be gained.
But I doubt very much that all of the four dozen people who found themselves caught by that eruption were fully informed of the dangers when they stepped into that crater. Many of them probably thought the government would never let a tour company operate there if it wasn't safe. We tend to trust governments and companies to be looking out for us. We tend to assume it must be okay if the boats are still sailing.
The Whakaari / White Island tragedy is telling us that this is not a safe assumption to make.
Companies earning their money by taking people into danger will too often ignore the odds against their enterprise. Even the ones trying their hardest to keep you safe will sometimes miscalculate. And none of them can prevent natural hazards from being hazardous. They can't calculate the trajectory of every volcanic bomb. They can't anticipate every phreatic eruption. They can't know for sure if a volcano is safe to visit.
The government can't just immediately shut private entities on privately-owned land down every time the volcano grumbles. I'm sure many agencies would love to have that power, but we haven't granted it. And we know from the outraged howls of companies and residents on Mount St. Helens in 1980 just how likely it is that citizens will happily let the government mark private lands as no-go zones.
We can take this opportunity to make better rules. We can establish better safety protocols. We can try to do more. But as long as humans are fascinated by active volcanoes and want to see the action up close, there will always be casualties. There will always be a substantial risk to our health and safety.
So please consider carefully if the risk of losing your life is worth it before you go, and make yourself aware of the hazards and mitigation thereof as best as you can.
We'll talk about the Taupo Volcanic Zone soon, and how Whakaari / White Island just became its most notorious member. For now, I'll leave you with some early news links. (Keep in mind that some details will be wrong, others need modification or clarification, and that any time news reports talk about smoke coming from the volcano, they mean steam or ash. White "smoke"? That's steam. Gray"smoke"? That's ash. Volcanoes don't put out smoke. Vegetation on their flanks can catch fire and put off smoke, but that's not happening on poor, mostly bald Whakaari / White Island.)
BBC: White Island: The privately-owned New Zealand volcano that is always active
[Professor Jan Lindsay] said it was possible there was no magma involved in Monday's eruption, which may have made it harder to detect.
"If you have something that's being driven by the hydrothermal system it's... not like when you have a magma chamber building beneath the volcano and you get lots of seismic activity," she said. "If it's a shallow burp, you may not see that."
BBC: New Zealand volcano: White Island's eruption in pictures
Live Science: Why White Island Volcano Erupted Without Warning
Monitoring and warning for hydrothermal eruptions is a huge challenge. We don't normally see these eruptions coming, no matter how much we would like to. Many systems are already "primed" for such events, but the triggers are poorly understood.
The warning periods, once an event gets underway, are likely in the order of seconds to minutes. Our only hope for anticipating these events is to track potential vapour and liquid pressure in hydrothermal systems and to learn from their long-term behaviour when they are at a super-critical state. Unfortunately there are no simple rules that can be followed and each hydrothermal system is different.
In this age of technology and instrumental monitoring, it seems irrational that there should be little or no warning for such eruptions. The eruption is not caused by magma, but by steam, and this is much harder to track in our current monitoring systems.
And, finally, Erik Klemetti's sadly prescient article, which saw this tragedy coming for years:
Rocky Planet: How Dangerous is Visiting New Zealand's White Island?
Does this mean that tours shouldn't happen? It is a tricky question. I was in New Zealand in 2009 and considered taking the White Island tour. However, the more I thought about it, the more it bothered me that these tours, although offering warning to tourists of the potential dangers, are potentially the perfect cocktail for a Galeras-like tragedy.