About 300 miles off the coast of Oregon, an underwater volcano appears to be rumbling to life.

Scientists who have been monitoring the vast submarine volcano for decades say a flurry of recent activity — including an uptick in earthquakes in the vicinity, and swelling of the structure itself — signals that it’s ready to erupt.

Current forecasts project that the volcano, known as Axial Seamount, could erupt anytime between now and the end of the year, according to Bill Chadwick, a volcanologist and research professor at Oregon State University.