By Sid Perkins
When a set of instruments monitoring an underwater volcano got trapped in an eruption in early 1998, the scientists who had deployed the sensors ended up with considerably more data than they bargained for.
The sensors were deployed on the ocean bottom in October 1997 to monitor the slow heavings of Axial volcano, which breaches the Juan de Fuca undersea ridge and rises to an ocean depth of 1,500 meters about 400 kilometers off the coast of Oregon. By measuring the water pressure every 15 seconds, scientists could monitor long-term changes in ocean depth and thereby the rise and fall of the volcano’s summit, says Christopher G. Fox, a marine geophysicist at NOAA’s Pacific Marine Environmental Laboratory in Newport, Ore.