Volcano Danger: 18 U.S. Volcanoes Pose 'Very High Threat:' USGS

PORTLAND, OR – The pictures of flowing lava flowing from Kilauea and snaking its way to the Pacific captivated the world. According to a new report, that volcano is just one of 18 in the United States that are considered to pose a "very high risk."

The report – an update to the US Geological Survey National Volcano Threat Assessment – says that four of the volcanoes are in Oregon, four in Washington, three in California, five in Hawaii, and two in Hawaii.

"Large eruptions from any of these very high threat volcanoes could cause regional-or national-scale disasters," the report states.

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The report had last been updated more than a decade ago.

To develop the assessment, scientists looked at two dozen separate factors and applied them to 161 volcanoes.

Based on the assessment, the volcanoes were separated into five categories: Very High Threat (18), High Threat (39), Moderate Threat (49, Low Threat (34), and Very Low Threat (21).

The rankings are "not a forecast or indication of which volcanoes are most likely to erupt next," the USGS says.

"Rather, it is an indicator of the potential severity of impacts that may result from future eruptions at any given volcano."

While Kilauea sits atop the list, it is followed closely by two Washington volcanoes – Mount St. Helens and Mount Rainier, which last erupted in 1854.

When St. Helens famously erupted in 1980, a sizable piece of the mountain was destroyed in the explosion.

That sort of destructive force is something that the USGS warns is possible with Washington, Oregon, and California volcanoes "where explosive and often snow and ice covered edifices can project flowage hazards long distances to reach densely populated and highly developed areas."

Not far behind Rainier is California's Mt. Shasta and Mt. Hood and Three Sisters in Oregon.

A report earlier this week found new fault lines beneath Hood that could cause a massive earthquake.

Of all 161 volcanoes, the report concluded that St. Helens poses the greatest risk to aviation.

At the bottom of the list of the very high threat volcanoes is the Long Valley Caldera in California. Earlier this year, scientists determined that 240 cubic miles of magma sitting below the surface.

Scientists say while Long Valley has not erupted in 100,000 years, they have noticed more activity over the past 40 years. Still they believe that the super volcano does not pose an imminent threat.

The report found that 12 volcanoes saw their threat risk rise since the last report including Newberry Volcano in Oregon and Yellowstone in Wyoming.

The USGS says that since 1980, there have been 120 eruptions and 52 incidents of notable volcanic unrest at 44 volcanoes in the United States.

YOU CAN READ THE WHOLE REPORT HERE

Photograph of lava flows from Kilauea by Ben Gaddis, U.S. Geological Survey.