As if the threat of an epic, world-shattering earthquake wasn't enough to keep Northwest residents up at night, now a study supposedly says Mount St. Helens is about to let off another violent eruption.
Just look around the Internet.
Tech Times asks: "Could Mount St. Helens erupt again?"
"New imagery reveals that Mount St. Helens is sitting atop a small sea of magma," reads the headline from the geeky Motherboard site.
"Tremors around St. Helens may hint at a new eruption," ZME Science declares.
The response from geoscientists: No. Wrong. Say what?
In a case of click-baiting trumping solid science reporting, media outlets around the world are somehow misinterpreting (or intentionally conflating) research presented at last week's annual Geological Society of America meeting in Baltimore, according to the study's chief researcher.
Rice University geophysicist Alan Levander said there's "nothing sensational" about the report he presented last week with Rice seismologist Eric Kiser.
Mount St. Helens is responsible for the most deadly eruption in U.S. history, killing 57 people and wiping out forests, homes and highways in a blast zone that stretched to biblical proportions on May 18, 1980.
"There is no indication that Mount St. Helens is about to erupt again," Levander said.
The research is part of a $3 million campaign involving several universities, including the University of Washington and Oregon State University, to map out the 8,363-foot volcano's subterranean guts.
The project is called "imaging magma under St. Helens," or iMUSH.
Levander said iMUSH has indeed discovered three massive chambers deep below and east of the peak. However, the newly discovered zones, ranging from 3 to 25 miles below sea level, are not magma chambers full of molten rock pushing toward an eruption, as some newspapers and websites have reported.
"That's a complete fabrication," Levander said. "These are not lava lakes."
The reports of an impending eruption, he said, may have started with a misleading graphic on the Science Magazine website, creating a chain reaction of news outlets trying to serve up stories that would get clicks.
Take a deep breath and check out the key findings from the pioneering imaging research:
- The newly discovered chambers are actually storage zones that are "bodies of rock with surprisingly tiny amounts of melt," Levander said, comparing them to geological sponges that they could eventually be filled with magma. "But these are not lava lakes right now."
- The Mount St. Helens and Mount Adams volcanic systems may be connected in the Earth's crust.
- By setting off explosive devices around Mount St. Helens, scientists were able to map out the mountain's volcanic guts beyond the existence of a single, known magma chamber under the rumbling, steaming caldera.
- It is now believed that significant magma movement between the chambers triggers earthquakes and could help better predict the next big eruption in the Cascades. But, as Levander reiterated, there is no indication that another eruption is imminent.
So, you can go back to bracing for the next Cascadia subduction zone earthquake, at least until Oregon State researchers release the next round of research from the iMUSH campaign within the next few months.
Time to really geek out. Here's what the illustration of the iMUSH research shows, according to Levander:
"What we measure are the velocities of seismic waves in the earth.
There are 2 types of seismic waves, P or compressional waves (volumetric change) and S or shear waves (bending)
P waves travel at speed Vp, S waves travel at speed Vs.
Both Vp and Vs in rocks are reduced by heat, and by fluids in the rock, Vs more than Vp. In other words both P waves and S waves slow down, but S slows down more relative to P.
If you take the ratio of Vp to Vs it appears high if the rocks have a small amount of fluid, because Vs is more affected than Vp.
We identify low Vp areas and high Vp/Vs areas as potential magma storage areas, if there is another line of evidence.
The top of the one directly under MSH was imaged in 2009 by Waite and Moran, and seismicity during the 1980 eruption occurs all through it.
The deep low Vp zone has Deep Long Period Earthquakes associated with its side, and these are often associated with presence of magma.
The other one is beneath the Indian Heaven volcanic field, but there are no earthquakes linking it with the deep low Vp body."
-- Joseph Rose
503-221-8029
jrose@oregonian.com
@josephjrose