Scientists at the University of Washington have developed seafloor sensors that can detect underwater pressure changes to monitor the movement of the magma of an underwater volcano.

The depth instruments were developed by Bill Chadwick, an oceanographer at Oregon State University and the National Oceanic and Atmospheric Administration. He predicted that the Axial Seamount, an active underwater volcano located 480 kilometers west of Cannon Beach, Ore., will erupt in 2015. The volcano's last known eruption was in 2011.

The three sensors were installed on the caldera, or crater, of Axial Seamount. The researchers discovered that the number of earthquakes in the volcano increased from hundreds to thousands per day. They also found that the center of the crater lowered by about 2 meters within 12 hours.

The more frequent earthquakes and sudden drop of the crater, according to researchers, indicate that the magma has started moving to the east side of the crater. The sensors captured up to 200 shakings per second around the caldera at the base of the underwater volcano.

"It isn't clear yet whether the earthquakes and deflation at Axial are related to a full-blown eruption, or if it is only a large intrusion of magma that hasn't quite reached the surface," Chadwick said in the university news release. "There are some hints that lava did erupt, but we may not know for sure until we can get out there with a ship."

The researchers plan to visit the underwater volcano in August to confirm if there was really an eruption. For now, they are satisfied with the performance of the sensors, as the technology allowed them to monitor seismic activity remotely.

"It was an astonishing experience to see the changes taking place 300 miles away with no one anywhere nearby, and the data flowed back to land at the speed of light through the fiber-optic cable connected to Pacific City -- and from there, to here on campus by the Internet, in milliseconds," John Delaney, a UW professor of oceanography who led the installation of the instruments as part of a larger effort sponsored by the National Science Foundation, said in a statement.