PORTLAND, Ore. (KOIN) — Amid concerns of a volcanic eruption in Iceland following seismic activity, experts say residents in the Pacific Northwest should not be concerned about an eruption, even after hundreds of earthquakes have been detected near Mt. St. Helens since mid-July.
Residents in the fishing town of Grindavik, Iceland evacuated their homes on Nov. 11 amid concerns of a pending volcanic eruption, as reported by the Associated Press. Even though over 400 earthquakes have been detected near Mt. St. Helens since mid-July, one expert says the Pacific Northwest doesn’t need to worry about an eruption.
“They’re two completely different types of eruptions,” said Dr. Scott Burns, professor emeritus of engineering geology at Portland State University.
Burns — who leads trips to Iceland every year for the Smithsonian — explains that Iceland is on the mid-Atlantic Ridge, where the European and North American tectonic plates are separating. He says magma comes up all the time at different places on the island.
“The good news is that it is an ‘oozer,’ it’s very dark magma and eventually solidifies and forms basalt — which all 90% of Iceland is basalt,” Burns said. ” It’s only rarely that you have a very big explosive type of eruption.”
Geologists can detect if magma is coming up from underneath a volcano if there’s a swarm of small earthquakes that are less than one magnitude, Burns said — noting officials in Iceland have been following the potential for an eruption because the country has experienced these earthquakes on and off for the last five years.
“When [magma] comes up, it forms a little kind of what we call a ‘cinder cone’ or ‘spatter cone’ and magma goes up and it’s not violent. People can come in and, and at a distance, watch it,” Burns said.
He added that experts are concerned about an eruption in Iceland now, because “all of the earthquakes that are occurring are in a line and at the end of the line is [Grindavik] with like 3,500 people in it.”
“They are scared that the cracks and crevices are going to open up and magma is going to start coming out just north of town and work its way right down into the town. And so, you’re dealing with lives that are there. And so, they’re doing the right thing in evacuating the town,” Burns said.
He pointed out that a potential eruption could destroy Iceland’s number one tourist destination: Blue Lagoon.
However, he says experts aren’t worried about a similar situation after Mt. St. Helens’ recent seismic activity, in part, because it’s a different type of volcano.
“It’s a more explosive volcano, and since it came back to life on May 18th of 1980, it’s gone through periods of coming back to life and then no activity, back to life and no activity,” Burns said of Mt. St. Helens.
He added that magma is coming into Mt. St. Helens’ crater and forming the dome.
Burns says this is less of a concern because “[the] number one thing is nobody lives around there. And this type of eruption is not as explosive as the May 18th, 1980 one, and it’s been doing this for the last 20 years.”
He furthered that the United States Geological Survey has seismographs to track earthquakes on all of the volcanoes of the greatest concern in the Pacific Northwest — including Mt. St. Helens, Glacier Peak, Crater Lake, and Mt. Lassen.