Researchers claim volcanoes can become active in short time

Mount_Hood

Researchers at a pair of Western US universities report they have uncovered a key factor in predicting volcanic eruptions.

Geologists from the University of California-Davis and Oregon State University have found that in order for a volcanic eruption to occur, molten rock under the volcano must be sufficiently mobile. This occurs when the temperature of rock below the volcano rises to more than 1,328 degrees Fahrenheit.

The researchers developed their findings by studying Oregon’s Mount Hood, located in Cascade Range, about 50 miles east of Portland.

“The team found that the magma located roughly three miles beneath the surface of Mount Hood has been stored in near-solid conditions for thousands of years,” according to RedOrbit. “However, they say that it takes just a significantly short period – perhaps as little as a few months – for said magma to liquefy and potentially lead to an eruption.”

The belief that there is a big reservoir of liquid magma under an active volcano is not always true, said Kari Cooper, lead author and an associate professor at UC Davis.

“The study team said that mobility of the magma depends on the amount of crystallization,” according to RedOrbit. “When it is more than about 50 percent crystalline, it becomes immobile. Crystallization, in turn, depends on the temperature of the rock.

“If the temperature of the solid rock rises to more than 1,328 degrees F, which can happen when hot magma rises up from deeper within the Earth’s crust, an eruption may be imminent,” the online publication added.

“If the temperature of the rock is too cold, the magma is like peanut butter in a refrigerator,” Oregon State University professor Adam Kent said in a statement. “It just isn’t very mobile. For Mount Hood, the threshold seems to be about 750 degrees (C) [1,328 Fahrenheit] – if it warms up just 50 to 75 degrees above that, it greatly increases the viscosity of the magma and makes it easier to mobilize.”

Mount Hood has had at least four major eruptive periods during the past 15,000 years. The last three occurred within the past 1,800 years. The last of these took place around 170-220 years ago, shortly before the arrival of the Lewis and Clark Expedition in 1805, according to the website www.mounthoodhistory.com.

For the study, researchers studied rocks ejected from Mount Hood’s previous eruptions. By analyzing the radioactive isotopes and the distribution of trace elements, the team was able to reconstruct the history of the rocks and the conditions they were exposed to before the volcano erupted, according to RedOrbit.

The results of their findings could make it much easier for volcanologists to assess when a volcano is ready to explode. If eruptible magma is indeed relatively rare, then when it does appear, the risks of an eruption are much higher, Cooper noted.

(Top: Oregon’s Mount Hood, part of the Cascade Range.)

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8 thoughts on “Researchers claim volcanoes can become active in short time

    • I think the researchers were focusing on volcanoes considered to be pretty much inactive. I’m not sure there’s much you can do about the slow-moving lava flows except keep an eye on them and then evacuate.

  1. I never know what to expect when I read your blog, Cotton. This was a surprise to have you discussing Mt. Hood. We used to live not far from there in Portland, and when we moved there from flat Indiana we learned what direction we were heading by looking for either Mt. Hood or Mt. St. Helens. Then, of course, Mt. St. Helens got tired of being our compass and blew her top. We always knew it could happen to Mt. Hood, too, but hoped it wasn’t eminent. Now we live in the foothills of the Sierra Nevada. Let’s hope the whole range doesn’t blow! 🙂 I’m going to work really hard not to peak their anger, and get them boiling mad! 🙂

    • Marsha, that must have been something to have suddenly lost one of your key compass points! I was living in Colorado when Mt. St. Helens erupted and remember seeing ash on my parents’ car, even though it was at least 1,000 miles away.

      The good thing about the Sierras and Cascades is that erupt very infrequently. The bad thing is that they do still occasionally erupt, and it’s difficult to tell when. I’ve got a feeling you’re on their good side. 😉

      • By the time Mt. St. Helen’s erupted my husband and I had moved to Cottage Grove, OR, a hundred miles south. We had ash, and I had the best batch of strawberries the next year! My dad lived in IN, and HE had ash! It was an amazing explosion.

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