Chuck Bednar for redOrbit.com – @BednarChuck
Predictions that an active underwater volcano located some 300 miles off the Washington and Oregon coasts would erupt sometime this year may have come true, as Axial Seamount appears to have shown signs indicative of an eruption over the past few weeks.
Credit: Bill Chadwick, Oregon State University
While the region has started experiencing thousands of tiny earthquakes over the past few days (a sign that magma is moving towards the surface) and the seafloor has dropped by nearly eight feet, the volcanic activity has yet to be confirmed, according to Oregon State University.
Provided the eruption can be verified, it will prove that forecasts made by OSU professor Bill Chadwick and Scott Nooner of the University of North Carolina-Wilmington in September 2014 were correct. Chadwick and Nooner predicted that such an event would occur this year during a public lecture and blog posts, and was repeated by the duo last week at a workshop.
Basis of their forecasts
Their forecasts were based on previous research, funded by the US National Science Foundation (NSF) and the National Oceanic and Atmospheric Administration (NOAA), which demonstrated how the volcano repeatedly inflates and deflates like a balloon in response to magma inflow.
“Basically, we have been following a pattern of the volcano inflating with magma between eruptions and then deflating during eruptions,” Chadwick, who is also affiliated with the NOAA Pacific Marine Environmental Laboratory, told redOrbit via email. “The seafloor actually moves up and down and we measure that with precise pressure sensors.”
“This sort of thing is measured at volcanoes on land with GPS and other methods, but this is the first time we’ve done this on a submarine volcano,” the professor added. “We think the volcano has erupted because we are seeing temperatures rise on instruments connected to a new cabled observatory that reaches out to the seamount. We don’t know for sure though, and probably won’t know until we can go out there with a ship within the next few months.”
Chadwick admitted in a statement that he had some doubts about the prediction even the night just before the volcanic activity started, since he and Nooner had no real certainty that it would take place. He said it was more of a way to test their hypothesis about the pattern they observed, and that it was both repeatable and predictable in nature.
An opportunity to learn more about volcano systems
Since Axial Seamount is so close to the northwest coast, and because it has a unique structure (it is on very thin ocean crust and has a simpler “plumbing system” than most land-based volcanoes, according to Chadwick), it can reveal much about the inner-workings of volcano magma systems and help experts determine if and how eruptions could be effectively predicted.
“With the new cabled observatory, Axial Seamount is a place where we can learn a lot about submarine volcanism (the most common kind on Earth), how volcanic events perturb the local hydrothermal vents and biological communities, and we can learn about what happens before, during, and after eruption, what observations can be used to predict them, and then how that information can be applied to more complicated volcanic systems on land,” he told redOrbit.
One of three bottom-pressure/tilt instruments in the summit caldera at Axial Seamount that is connected to the OOI Cabled Array network. This instrument measured vertical movements of the seafloor during the recent volcanic eruption. (Credit: National Science Foundation/Ocean Observatories Initiative, University of Washington, Canadian Scientific Submersible Facility)
Chadwick added that the potential activity at Axial “has no impact on the Cascadia subduction zone and has not increased or decreased the risk of a large coastal earthquake. The seismicity at Axial is very small and there is no risk of the volcanic activity causing a tsunami. Even if Axial is erupting lava (which we think it is), this will have no effect on the surface ocean – Axial is too deep (1500 m depth) and it is virtually impossible for heat release from the seafloor to make it to the ocean surface.”
He and Nooner plan to return to Axial in August to gather more data, but OSU said that it may be possible for other experts to visit the seamount earlier than that, with an expedition possible as soon as this month. They hope to confirm that there was an eruption, and if so, to measure the volume of lava that was involved with the event, the university noted.
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