U.S. scientists say the eruption of an undersea volcano off the Oregon coast marks the first successful forecast of such an ocean eruption. Researchers at Oregon State University say the eruption occurred on the Axial Seamount about 250 miles off the coast, one of the most active and intensely studied seamounts in the world. Bill Chadwick, an OSU geologist, and Scott Nooner of Columbia University have been monitoring the seamount for more than a decade, and in 2006 published a paper in which they forecast that Axial would erupt before the year 2014. "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," Chadwick said Tuesday in an OSU release. They used ocean bottom sensors to measure vertical movements of the floor of the volcano's caldera and found the volcano was inflating at the rate of six inches a year, indicating that magma was rising and accumulating under the volcano's summit. The volcano's last eruption was in 1998. "It is now the only volcano on the seafloor whose surface deformation has been continuously monitored throughout an entire eruption cycle," Nooner said.