NEWPORT, Ore. – The undersea geology world is buzzing about the recent discovery that the Axial Seamount – an undersea volcano about 250 miles off the Oregon coast – has erupted. But what has everyone excited is that the eruption had been forecast by a team of scientists who’ve been monitoring the mount for years.
It’s being called the first-ever successful forecast of an undersea volcano.
Bill Chadwick, an Oregon State University geologist based at the Hatfield Marine Science Center, and Scott Nooner, of Columbia University, have been monitoring Axial Seamount for more than a decade, and in 2006 published a paper in the Journal of Volcanology and Geothermal Research in which they forecast that Axial would erupt before the year 2014. Their forecast was based on a series of seafloor pressure measurements that indicated the volcano was inflating.
“Volcanoes are notoriously difficult to forecast and much less is known about undersea volcanoes than those on land, so the ability to monitor Axial Seamount, and determine that it was on a path toward an impending eruption is pretty exciting,” said Chadwick, who was chief scientist on the recent expedition, which was jointly funded by the National Oceanic and Atmospheric Administration and the National Science Foundation.
Axial last erupted in 1998 and Chadwick, Nooner and colleagues have monitored it ever since. They used precise bottom pressure sensors – the same instruments used to detect tsunamis in the deep ocean – to measure vertical movements of the floor of the caldera much like scientists would use GPS on land to measure movements of the ground. They discovered that the volcano was gradually inflating at the rate of 15 centimeters (six inches) a year, indicating that magma was rising and accumulating under the volcano summit.
When Axial erupted in 1998, the floor of the caldera suddenly subsided or deflated by 3.2 meters (10.5 feet) as magma was removed from underground to erupt at the surface. The scientists estimated that the volcano would be ready to erupt again when re-inflation pushed the caldera floor back up to its 1998 level.
“Forecasting the eruption of most land volcanoes is normally very difficult at best and the behavior of most is complex and variable,” said Nooner, who is affiliated with the Lamont-Doherty Earth Observatory. “We now have evidence, however, that Axial Seamount behaves in a more predictable way than many other volcanoes – likely due to its robust magma supply coupled with its thin crust, and its location on a mid-ocean ridge spreading center.
“It is now the only volcano on the seafloor whose surface deformation has been continuously monitored throughout an entire eruption cycle,” Nooner added.
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NEWPORT – Oregon State University geoscientist Peter Ruggiero will speak at the Hatfield Marine Science Center tonight (Oct. 25) on “The Role of Sea Level Rise and Increasing Storminess in PNW Coastal Change and Flood Hazards.”
