Experts Warn 8 California Volcanoes “Likely To Erupt”

With the looming threat of 8 volcanoes likely to erupt in California, the world’s top volcanologists are heading to Portland, Oregon on Aug. 14. They will be attending the first international volcanology assembly held in the U.S. since 1989.

From the Cascade Mountains, down to southern California, the West Coast contains some of the country’s highest-threat volcanoes, according to the United State Geological Survey.

While Mount Shasta unsurprisingly tops USGS’s list of very-high threat volcanoes in California, there are seven other volcanic areas in the state that are also young, nervy, jacked up on magma and “likely to erupt,” reported SF Gate.

Scientists are able to tell from geophysical and geochemical research that these volcanoes have magma, “in their roots,” said Margaret Mangan, Scientist-in-Charge at the California Volcano Observatory. “I call them the watch-list volcanoes.” 

USGS caption: Volcanoes of very high to low threat are scattered throughout California, from the Oregon border (north) to Mexico (south). Other older volcanoes in California are of less concern. California’s volcano watch list is subject to change as new data on past eruptive activity are collected, as volcanic unrest changes, and as populations in threatened areas grow or decline.

According to the California Observatory, the 8 fall into three danger categories:

  • Very-high threat: Mount Shasta, Lassen Volcanic Center and Long Valley Volcanic Region
  • High threat: Clear Lake Volcanic Field, Medicine Lake Volcano and Salton Buttes
  • Moderate threat: Ubehebe Crater and Coso Volcanic Field

Among the 18 “very high threat volcanoes,” in the U.S., 11 are along the Cascade Range in three states (Alaska and Hawaii have the others):

  • California: Lassen Volcanic Center, Long Valley Caldera, Mount Shasta
  • Oregon: Crater Lake, Mount Hood, Newberry, South Sister of The Three Sisters
  • Washington: Baker, Glacier Peak, Rainier, St. Helens

“We live on a fascinating planet,” Ewert said of the likelihood of eruptions along the West Coast, “and one of the reasons it is fascinating is that it is dynamic. The entire surface of the Earth is in motion and sometimes people have a hard time wrapping their head around that. We have big earthquakes. We have volcanic eruptions, tsunamis. All these things happen.”

Ewert explained the volcano threat list was not simply created to alert people that the Earth is petulant, but also to determine which of the country’s volcanoes need extensive monitoring.

According to the SF Gate, he said the team used 25 factors to determine a volcano’s danger status:

What has the volcano done in the past? What’s its modus operandi? When does it tend to erupt? What kind of phenomenon does it produce? Lahars (mud slurries of ice, rocks and other debris)? Pyroclastic flows (hot gas, rock and other stuff out of the volcano)? Is it a highly explosive volcano? How active is the volcano right now? Are there seismic swarms? Is it emitting hot volcanic gases? Is the edifice changing its shape (deformation)?

In addition to the geophysics of a volcano, the team examined how many people live or work near it, plus the amount and type of infrastructure has been built up around it … power generation, port facilities, etc.

The team also considered, What is the aviation exposure? How many flights a day pass through the volcanic airspace?

“If it is an explosive volcano,” Ewert said, “we asked how close is it to an airport and what is the daily passenger load of the airport? Recall in 2010, the eruption of the Eyjafjallajökull in Iceland shut down European airspace for over a week. That ran up about a $10 billion impact cost. Given the fact that an explosive eruption can put an ash cloud up to cruise altitude in five minutes or less, that volcanic airspace is an important thing to take into consideration.”

“Over the northern California volcanoes, the data from FAA suggests that there are a couple hundred jumbo jets on flight-lines that pass over those three volcanoes on a daily basis,” Mangan said. “And, likewise there are a couple hundred jumbo jets that are flying over Long Valley Volcanic Region as well.”

Mangan said these 8 riskiest volcanoes in California need monitoring.

“… so that we can forecast eruptions, essentially keep our finger on the pulse,” she said. “The best network, the optimized network that we currently have, is in the Long Valley Volcanic Region. It is arguably one of the best in the nation. It is also one of the most restless volcanic areas currently.”



It sounds like these 8 volcanoes could erupt anytime. We should have more information after the meeting on August 14.

(Article By Jeremiah Jones)


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