Volcanoes can kill you in many different ways. Are you on their slopes? A volcanic avalanche of superheated ash and gas or a sneaky lava flow would do it. Far across the bay? A tsunami caused by a collapsing flank will be delivered to your door. On the other side of the planet? The aerosols jettisoned into the stratosphere will tamper with the climate, leading to deadly droughts in one place and fatal floods in another.
Volcanoes can also launch chunks of freshly baked volcanic rock into the sky that, even before they have cooled down and properly solidified, can land on you and send you into the great beyond.
A team of scientists in New Zealand wanted to know how roofs in Auckland—the country’s largest city and one that sits on a huge field of volcanoes—would stand up to a future ballistics-throwing eruption. They couldn’t just walk around the streets lobbing volcanic rock at people’s houses, so they did the next best thing: They built a cannon, loaded it up with volcanic rocks, and blasted them at replica-but-realistic roofs, watching to see what it takes to dent, bent, and break them.
Volcanologists conduct experiments in laboratories all the time to try to shrink complex natural phenomena down to a scale at which scientific interrogation is possible. But it’s safe to say that this project is arguably one of the most fun. “Come on,” said Rebecca Williams, a volcanologist at the University of Hull in England who wasn’t involved with the research. “Who doesn’t want to fire volcanic cannonballs at roofs?”
Volcanic bombs (still partially molten when ejected) and blocks (already solid chunks) can and have hit people. Kīlauea’s prolific 2018 eruption sequence, which mostly involved lava flows, did occasionally surprise everyone with an explosion. A volcanic bomb the size of a basketball shot out of the sea at one point, crashing through the roof of a tour boat like a shotgun blast from hell, injuring over a dozen people. Back on land, another bomb smashed through a man’s shin, shattering the bones all the way down to his foot.
You may think the scariest feature of these ballistics is that they can be several times hotter than boiling water. True, the sautéed skin part is grim, but more often than not, the deadliest factor is that both bombs and blocks can weigh as much as a refrigerator and can easily travel at 230 miles per hour. They pack one heck of a punch and can hit someone 6 miles away from the volcano itself. “That’s astonishing, for something that goes from fist-size to van-size,” said Williams.
It hasn’t escaped the attention of volcanologists that New Zealand’s North Island and its surroundings are profoundly volcanic. Some of these volcanoes, being near people and capable of all kinds of eruptions, can be hazardous.
Auckland, home to 1.7 million humans, overlaps the appropriately named Auckland Volcanic Field, a zone of 53 individual volcanic centers that have erupted in a cornucopia of ways. The most recent eruption, about 600 years ago, was the only one witnessed by people. During a violent eruption in which lava mingled explosively with seawater, it created the 4-mile Rangitoto Island, a rubbly, undulating spot draped by hardened lava.
Another Auckland Volcanic Field eruption at some point in the future is inevitable, which won’t be great news for the city that now sits atop it. “It’s not just the normal uncertainty of what the eruption is going to be like,” Nicole Allen, a PhD student at the University of Canterbury in New Zealand, told Gizmodo. “It’s where it’s going to be, and we just don’t know.”
This inevitable future disaster is why DEVORA—that’s DEtermining VOlcanic Risk in Auckland—was launched in 2008. Led by volcanologists at the University of Auckland and GNS Science, a vast number of scientists, engineers, emergency managers, economists, social scientists and others are cooperating to better understand the risks to the metropolis from the next eruption. This work includes improving their understanding of how the volcanoes work and the effects their eruptions may have on the city’s infrastructure, from short-circuiting its power grid to blocking up sewers.
Firing volcanic ballistics at roofs falls under DEVORA’s umbrella. Involving Allen and led by Tom Wilson, a disaster risk and resilience researcher at the University of Canterbury, this project wants to answer a pretty simple question: Can local roofs hold up against an onslaught of volcanic debris?… Via – Gizmodo