Axial Seamount, an underwater volcano off the coast of Oregon, is believed to be very active — coughing up lava about a mile beneath the sea’s surface. Researchers were made aware of the volcano when major changes in seafloor elevation began and numerous tiny earthquakes started shaking up things on April 24.
According to LiveScience, an eruption of the Axial Seamount was predicted by geologists Bill Chadwick — from Pacific Marine Environmental Laboratory and Oregon State University — and Scott Nooner — University of North Carolina. The two wrote a blog post in September, 2014, on PMEL about it. The scientists have been monitoring this volcano for 15 years by measuring small movements in the ocean floor. The volcano would balloon with magma, then deflate. Axia Seamount has erupted twice — once in 1998, and again in 2011.
The undersea volcano is 3,000-foot-high structure from the ocean floor. It accompanies a number of volcanoes that “straddle the Juan de Fuca Ridge, a tectonic-plate boundary where the seafloor is spreading apart.”
An image of the underwater volcano can be viewed here.
Chadwick tells LiveScience that the sea volcano is “like a balloon.”
“It’s kind of like a balloon — as magma is going into the balloon, it’s inflating, and it pushes the seafloor up. As more and more magma gets in, the pressure builds. Eventually, it reaches some critical pressure where [the seamount] can’t hold it in anymore, and then it squirts out.”
The deflation occurs whenever the sea floor drops down drastically after the eruption — “like letting air out of a balloon,” Chadwick adds. Last week, the center of the volcanic crater dropped about 8-feet within a 12-hour period. Not only that, but the amount of tiny earthquakes went from hundreds per day to thousands. When the April 24 explosion happened, there were 8,000 earthquakes that day.
As the report also says, the earthquakes are so small that they won’t cause harm to coastal residents or spark a tsunami.
Chadwick and other researchers were able to observe the eruption “in real time.” There were instruments connected to shore by a fiber-optic cable that was installed by the University of Washington and funded by the National Science Foundation. This is what makes Axial Seamount the world’s first “wired volcano.”
Changes in water pressure are measured by sensors. Whenever the volcano inflates or deflates, this affects water pressure, which installed seismometers record.
Chadwick and Nooner will further observe Axial Seamount by ship this summer in order to see if the volcano had finished erupting. There’s also data they need to document that isn’t connected to the cable observatory.
“The goal is to understand the basic behavior of volcanoes, because we really don’t understand how magma chambers work and how magma works its way up through the crust,” Nooner said.
[Photo by Wolfgang Kaehler/LightRocket via Getty Images]