Deep-sea volcano off the Oregon Coast helps scientists forecast eruptions
Scientists forecast deep-sea volcanic eruptions off the Oregon Coast. Learn more here.
Oregon Public Broadcasting | By Jes Burns
A thick blue-white haze envelops the Research Vessel Thompson as it floats 250 miles off the Oregon coast.
Akel Kevis-Stirling’s orange life vest and blue hardhat are vivid pops of color in the fog.
“You guys ready to go?” he calls into his radio.
The person on the other end crackles an affirmative.
“Copy that,” he says and looks up across the rear deck of the research ship. “Alright, straps!”
The crew of the ROV Jason jumps into action, removing the straps that secure the cube-shaped submarine to the deck. The remotely-operated sub, with a base the size of a queen mattress, is loaded with scientific instruments it will carry down to the seafloor.
Kevis-Stirling gets final permission from the Thompson’s bridge for the launch.
“Ok, here we go. Jason coming up and over the side,” he calls. “Take it away Tito!”
The crane operator, Tito Callasius, lifts the submarine and swings it over the side of the ship into the water. A plume of fine bubbles rises through the waves as Jason starts its mile-long descent to the Axial Seamount, a deep-sea volcano that’s erupted three times in the past 25 years.
The scientific instruments on the sub — called bottom pressure recorders — will help reveal the inner workings of the Axial Seamount. And they could help us understand volcanic risk closer to home.
“As magma rises up underneath and accumulates under the surface, the whole volcano inflates like a balloon… pressure builds up,” says Bill Chadwick, the Oregon State University volcanologist who’s leading the cruise that took researchers out to sea for two weeks last summer. “Eventually that magma opens up a crack, finds a way out, erupts lava on the seafloor. [Then] the whole volcano quickly subsides back down.”
It’s a little counterintuitive, but the more the volcano seafloor rises, the less water it has on top of it. And the less water there is pressing down, the lower the water pressure readings on the ocean floor.
“As inflation is happening in the volcano, we will see a corresponding decrease in pressure in these instruments on the surface [of the volcano],” says Scott Nooner, a professor of geophysics at University of North Carolina Wilmington who has been making research trips out to Axial for 20 years.
The bottom pressure recorders use this change in water pressure to reveal how much the volcano has grown.
Chadwick says the surface of Axial will rise 8-10 feet as it builds towards eruption.
“That’s a lot of motion,” he says.
By collecting data year after year, the researchers, whose work and expedition were funded by the National Science Foundation, can track changes in the volcano as it inflates with magma to a literal breaking point.
Chadwick’s overall goal is to better understand how Axial and other volcanoes work, but the frequent eruptions of this deep-sea volcano sparked his interest in another, more practical, goal.
“By seeing that pattern a few times now, we can try to anticipate when the next eruption’s going to be,” he says.
Volcanologists can often forecast the eruption of volcanoes a few days in advance, but predicting eruptions on a longer timescale is much more difficult.
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