Surprising Eruption in Japan: Geologists Explain the Risks of Volcano Tourism


(Photo: AP)

It’s a hiker’s nightmare: A nice hike on a beautiful fall day turns into a fight for survival when a quiet volcano erupts without warning, sending noxious ash into the air and leaving little hope of survival for whoever happens to be nearby.

That’s exactly what happened in central Japan on Saturday morning when Mount Ontake suddenly erupted. At the time, hundreds of hikers were on the mountain, taking advantage of the view and what officials say is a relatively easy three-hour hike to the summit. When the volcano erupted, some hikers sought shelter in a cabin. Others scrambled down the mountain to escape.

But some weren’t successful. More than 30 people are feared dead.

WATCH: Hiker in Japan films harrowing escape from erupting volcano

Volcanoes all over the world, from Hawaii to Indonesia, are popular hiking sites. After Saturday’s tragedy in Japan, a lot of outdoor travelers are left wondering if hiking on a volcano is a dangerous activity that we need to worry about.

Yahoo Travel reached out to volcanologists from all over the world to see what lessons, if any, outdoor adventurers can glean from the eruption of Mount Ontake:

How could this have happened so suddenly?


Ontake’s eruption sends plumes high into the sky. (Photo: AP)

No one can say for sure just yet. The Japan Meteorological Agency monitors volcanic activity and there’s no word on what it detected before Ontake blew its top. ”We don’t know what that monitoring was showing, or what the alert level was before the eruption,” says Brad Scott, a volcanologist with New Zealand’s Crown Research Institute of Geological and Nuclear Sciences.

But it looks as if this eruption happened without any warning. Early reports suggest it was a steam-driven explosion, which is nearly impossible to detect.

“It’s just groundwater that percolates deep into the volcano and interacts with magma that’s residing there,” says Patricia Nadeau, a volcanologist with New York City’s American Museum of Natural History. “It doesn’t give off a signal until it erupts.”

WATCH: RAW VIDEO - The eruption of Mt. Ontake

How often does this happen?


The tragedy at Mt. Ontake is believed to have been the result of a rare type of eruption. (Photo: AP)

"Steam-driven explosions are not all that common, so the Japanese were unlucky,” says Katharine Cashman, a volcanology professor at the University of Bristol in the U.K.

Still, the best predictor of future behavior is past behavior. And in this area, Mount Ontake’s record was far from unblemished.

“This particular volcano had a similar eruption in 2007,” Nadeau says. “That’s like yesterday in geological terms.” That recent incident made Ontake far more dangerous than a volcano whose last such eruption was several thousand years ago. “Knowing what I know about volcanoes,” she says, “I’m not surprised that a volcano that erupted in this style seven years ago did it again.”

What precautions should I take to avoid being near eruptions?


A hiker safely makes her way across the Tongariro alpine crossing in New Zealand. (Photo: Getty Images)

With a normal mountain, you can choose to climb spontaneously, just because it’s there. But if it’s a volcano, you need to do your homework first; before venturing, go online and check out the conditions.

“Geophysicists monitor volcanoes, and if they observe ‘long period earthquakes’ or other signs of activity (melting snow, souring of water, volcanic gas), they warn people ahead of time,” says University of Oregon geologist Ilya Bindeman. It’s best to heed those warnings. “Hikers should not approach an active, potentially explosive cone,” Bindeman says. “You can run away from lava but not from an avalanche or a pyroclastic cloud.”

Speaking of which, what should I do if I’m ever caught in an eruption like Saturday’s?


A hiker in Japan captures harrowing escape from Ontake’s fury. (Photo: Reuters)

As with surviving any explosion, Bindeman advises, “hide behind a sturdy object and run away.”

Not that that’s a foolproof strategy. “It would first be a matter of getting away from the main pyroclastic flow,” says Nadeau. “They travel very, very fast, so if you’re already in its path, there’s not much you could do.”

And then there’s the danger of ash falling from the sky. “You want to cover your face as best you can with some sort of mask or fabric,” Nadeau suggests. ”And try to take shelter in some sort of building, as long as it’s not raining wet ash that can collapse buildings.”

But if there aren’t any buildings available, as is often the case on a mountain, the right approach is the commonsense one. “I’d just cover my face and try to get down the mountain,” Nadeau says.

This all sounds dangerous. Should I just stay away from volcanoes altogether?


The spectacular volcanic craters at Haleakala National Park, Maui. (Photo: Getty Images)

You could, but it’d be your loss.

"In the grand scheme of things, you are safe on most volcanoes,” Nadeau says. “It’s like any daily risk you might take getting into a plane or a car.”

Related: Active Volcano Tours You Can Take

And as far as nature goes, risk is part of the territory. “There are many other aspects of wilderness that are also dangerous, but that does not mean that I would say to avoid going into wilderness areas,” says Cashman. “Instead, all one can do is to be aware and take reasonable precautions.”

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