admin
The ground beneath the Three Sisters volcanic region in Oregon has begun to swell… You know… in the same part of Cascadia that brought us Mt. Saint Helens? Yeah. In a statement, the United States Geological Survey has published that there is an uplift in a region of approximately 12 miles in area of almost an inch between June 2020 and August 2021.
In normal terms, a movement of an inch doesn’t seem like much, but in geological terms, it’s rather groundbreaking (*couldn’t resist). This uplift follows a history of about 25 years of measurable activity in the region and the geologists and volcanologists say that it’s occurring as magma fills in space beneath the surface about 3 miles Southwest of the South Sister peak at a depth of about 4 miles beneath the surface.
“The total is about 30 centimeters, which is about the size of a two-liter pop bottle,” said Emily Montgomery-Brown, a research geophysicist at the Cascades Volcano Observatory in Vancouver, Washington. “When this happens at volcanoes, there are often these pulses of lava. And they kind of push the top of the volcano out. It’s very slight. So, all of that’s happened in the last couple of months.”
Could This Be A Volcanic Eruption? Probably Not* (*With An Asterisk)
While the uplift that the USGS is seeing doesn’t necessarily mean that we’re starring down the barrel of the next Stromboli or Mt. Tambora. Montgomery-Brown said that an eruption isn’t expected and uplift isn’t the only preliminary sign of an impending eruption.
Typically an eruption is also presaged by the release of gasses and advancing series of small earthquakes which gradually become more powerful and frequent. So far, there have been a few bursts of tiny earthquakes in the area ranging from about 0.6 to 0.7 on the Richter scale along with the uplift, but there hasn’t been any outgassing yet.
According to KREM CBS2, “The Pacific Northwest Seismic Network at the University of Washington in Seattle monitors these seismic signals throughout the Cascades – cutting its teeth during the 1980 eruption of Mount St. Helens. Seismic Network Director Harold Tobin said that there’s nothing concerning about the earthquake activity around the Sisters.
But if Sisters is showing signs of activity, what does that mean for other Cascade volcanoes?
“The individual volcanoes are all part of the Cascade chain,” Tobin said. “But they are all individual volcanoes — they have a separate sort of plumbing system of magma. But something happening down there at Sisters in Oregon doesn’t mean that Mount Rainier is going to change its activity.”
So is there about to be an eruption? Are we about to see a fourth sister? No, probably not, but that’s with a pretty big asterisk since the uplift has been going since 1995 and we’ve seen a more significant uplift recently it could indicate an acceleration of the magma toward the surface.
In short: its hard to tell and the sisters will need much closer observation from here forward. The Three Sisters haven’t erupted since approximately 440 AD so its simpler to say the area is due.
