Magma Rising, But No Eruption Imminent At Mount St. Helens, Say Experts
redOrbit Staff & Wire Reports – Your Universe Online
While magma levels are rising at Mount St. Helens in Washington, there is now evidence that the active stratovolcano will not be erupting any time soon, researchers said during the annual meeting of the Seismological Society of America (SSA) in Anchorage, Alaska on Friday.
Lead researcher Seth Moran, a seismologist with the Cascades Volcano Observatory (CVO), explained that a small amount of magma began pooling approximately 2.5 to 3.0 miles beneath the roughly 8,300-foot volcano six years ago, according to a report published by FoxNews.com on Friday.
Scientists from the CVO and the Pacific Northwest Seismic Network (PNSN) “have been monitoring the subtle inflation of the ground surface and minor earthquakes” since the end of the 2004-08 eruptions at Mount St. Helens, said CBS News. The phenomenon is similar to those following the volcano’s 1980-86 eruptions, the news service added.
In a statement released by the US Geological Survey on Wednesday, the agency explained that Mount St. Helens is “showing signs of long-term uplift and earthquake activity,” but confirmed that there were “no signs of impending eruption.” They went on to explain that analysis from the CVO and PNSN monitoring revealed the magma reservoir beneath the volcano “has been slowly re-pressurizing since 2008.”
“It is likely that re-pressurization is caused by arrival of a small amount of additional magma 4-8 km (2.5-5 miles) beneath the surface,” the USGS added. “This is to be expected… and it does not indicate that the volcano is likely to erupt anytime soon. Re-pressurization of a volcano’s magma reservoir is commonly observed at other volcanoes that have erupted recently, and it can continue for many years without an eruption.”
Fifty-seven people died and over one billion dollars worth of property damage resulted from the 1980 Mount St. Helens eruption, according to Reuters. The eruption began with a 5.2 magnitude earthquake on the morning of May 18, and the surrounding area was decimated by “volcanic ash” and “rivers of hot mud and scorching pumice” during the course of the nine-hour eruption, the news organization added.
Moran assured residents in and around the volcano that no repeat of that incident is imminent, telling CBS News, “This is giving long-term (data) that it’s getting ready to erupt again, but it could be decades before it does something again. It’s getting ready, but it’s not there… It may stay perched at ready stage for a long time before it starts to erupt. The reassuring thing is: when it’s really ready to erupt, it gives lots and lots of signs.”