On May 18, 1980, Washington state’s Mt. St. Helens erupted in what would become the deadliest and most destructive volcanic eruption in the history of the continental United States. The resulting explosion cost fifty-seven people their lives and destroyed an estimated $1 billion USD worth of infrastructure. Some sources even claimed that several Bigfoot corpses were discovered on the mountain, although these have never been substantiated (of course).
Since the deadly eruption, the mountain has been the source of close seismological scrutiny in an attempt to prepare for or avoid the next major eruption. Just this week, however, geologists investigating the mountain have disconcertingly discovered that we might know much less about the deadly volcano than we think.
A team of researchers from the University of New Mexico and other U.S. institutions set off small explosives underground in order to map the magma chambers beneath the mountain. What they discovered is that the “heart” of the mountain, called the mantle wedge, is actually cold. According to their recent publication in Nature Communications, the researchers claim Mount St. Helens is a type of “thermal paradox,” generating heat where there should be none:
Mount St Helens therefore presents a thermal paradox because it lies directly adjacent to the cold mantle wedge and yet still produces arc derived magmatism which requires elevated temperatures.
That means the hot magma causing the mantle wedge to melt must come from another source and is funneled beneath Mount St. Helens through an unknown system of serpentine magma tunnels. Because the source of the heat is unknown, it could make predicting future eruptions more difficult. Lead author Steven Hansen stated in a UNM press release that this discovery ultimately raises more questions about the deadly volcano than it answers:
Given the unusual location of Mount St Helens, we think that this raises questions regarding the extent of the cold mantle wedge and the source region of melts that are ultimately responsible for volcanism.
The source of the magma is thought to lie far to the east of the mountain, where significant seismic activity has been detected lately. Could these foreshadow another deadly eruption? Let’s just hope it gets here before November 8th.