The lava beneath the world’s volcanoes lies more than 50 miles below the ground. Scientists have a general understanding on where this magma originated, but details on what’s happening so far in the ground have been slim.
A new study in the journal Nature has helped detail this process. A team of scientists used a slew of sensitive instruments to paint a better picture of what’s going on beneath Mt. Rainier.
Here’s what scientists found. About 50 miles below the surface, water escapes from the top of the Juan de Fuca plate. This fluid comes up and starts melting in the rock and pushes a mix of water and magma up in pretty much a straight shoot to a reservoir just below Rainier.
Check out the image below, courtesy of R. Shane McGary/Woods Hole Oceanographic Institution, for a better representation of Mt. Rainier’s magma interior. Figure A shows where the magma forms and its subsequent travel upwards in Figure B. Figure C is the magma reservoir below Mt. Rainier. Figure D shows where fluids released from the crust higher up eventually reach reservoir.
The study suggests Mt Rainier sits on top of a sizable amount of magma. Early evidence from other nearby volcanoes don’t show sizable amounts of melt beneath them. Does this mean Rainier is close to erupting? An imminent eruption is extremely unlikely. Yesterday’s study isn’t telling us when it might erupt. It just gives scientists a better look at the magma process below Mt. Rainier.
“This is the most direct image yet capturing the melting process that feeds magma into a crustal reservoir that eventually is tapped for eruptions,” says geophysicist Phil Wannamaker, of the University of Utah’s Energy & Geoscience Institute and Department of Civil and Environmental Engineering. “But it does not provide any information on the timing of future eruptions from Mount Rainier or other Cascade Range volcanoes.”
Scientists did find something odd. Part of Mt Rainier’s magma reservoir appears to be located about 6-10 miles northwest of the volcano. Scientists believe it’s a magma lobe extending outward from the main reservoir.