Will eruption on Hawaii trigger Northwest volcanoes? No, but ...

On Sunday, May 18, 1980 at 8:32 a.m., the bulging north flank of Mount St. Helens slid away in a massive landslide -- the largest in recorded history. Seconds later, the uncorked volcano exploded and blasted rocks northward across forest ridges and valleys, destroying everything in its path within minutes. (Photo courtesy of USGS)

CORVALLIS, Ore. – No, the eruption of Kilauea in Hawaii will not trigger an eruption in the Cascades, experts at Oregon State say.

“There is absolutely no linkage between the Hawaiian chain and the Cascade Range, and the geological environment is completely different,” said Oregon State University geologist Adam Kent, who has spent his career studying Northwest volcanoes.

But ...

"However," Kent said, "having said that – any time you live in a region of volcanoes, you should be vigilant. At some point, the Cascade volcanoes will erupt again, and it may even occur in our lifetimes.”

OK. Where?

We all know Mount St. Helens. The Washington volcano blew its top - and it's side - 38 years ago Friday.

In Oregon, the U.S. Geological Survey considers Mount Hood, the Three Sisters, Newberry Crater and Crater Lake as the volcanoes most likely to erupt.

In Washington, St. Helens, Mount Baker and Mount Rainier have the greatest potential to erupt.

“Only a handful eruptions have occurred in the Cascade Range since European settlement,” Kent said. “St. Helens, of course, erupted in 1980, and to a lesser extent, in the 2000s. And Lassen Peak erupted in 1915. Mt. Hood erupted in the 1780s, and Lewis and Clark could still see the effect on rivers when they arrived a couple of decades later.”

Over the past 4,000 years, the Cascades average about two eruptions per century, Kent said.

And Cascade volcanoes can go from zero to 60 in no time.

Kent published a study in 2014 that suggested Mount Hood "can switch from being dormant to active surprisingly quickly – in a matter of months – if the temperature of the rock elevates past a certain point and two types of magma mix.

“Part of being vigilant about Cascade volcanoes is being aware of what could happen and being prepared for when it does,” Kent said. “At some point in the future, all of the Cascade volcanoes will likely erupt. But we knew that before Mt. Kilauea began spewing lava.”

Althea Rizzo, Oregon Office of Emergency Management Geologic Hazards Coordinator, said the anniversary of the Mount St. Helens eruption and the ongoing eruption on Hawaii present a good opportunity to learn more about Northwest volcanoes.

“There are lots of places to get good information about volcanoes,” Rizzo said. “We live in a unique area that is geologically active, and understanding hazards posed by volcanoes in the Pacific Northwest is important because volcanoes have potential to cause problems.”

For example, volcanic eruptions can create debris flows called lahars, a mix of water and volcanic rock and ash.

If the vent of a Mount Hood eruption, the cement-like wall of volcanic mud would take around 3 hours to reach the mouth of the Sandy River, Kent said.

If you live between the two, you know you'd have to move fast in the event of an eruption.

“It is important to know what the hazards are for the areas you work and live in,” Rizzo explains. “We all have hazards to deal with. Once you know the hazard, you can plan.”

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