Minor Earthquake at Mount St. Helens
Date: 29-Nov-04
Country: USA
The mountain -- which in 1980 blew up with the eruption of a huge and deadly volcano -- has been spewing ash and steam since early October in a process of building a new lava dome, according to a USGS report.
The historic mountain has been closed to all climbers and visitors because of the emissions.
"Steam and gas emissions are occurring but nothing like the explosive level of 1980," said Stephanie Hanna, USGS spokeswoman.
The agency issued a Level 2 Volcano advisory, which means "an eruption could occur without warning, but an eruption is not imminently underway," which gives the agency time to prepare and alert public safety authorities, she said.
Twenty-four years ago, Mount St. Helens erupted, provoked by a 5.1 magnitude earthquake. The eruption killed 57 people and covered 230 square miles with ash and debris.
This autumn, small earthquakes have been occurring about once a minute at Mount St. Helens, according to the USGS report. The agency has issued a level 2 Volcano Advisory Alert, a mid-level warning, and an Orange aviation alert.
Hanna described the buildup of the lava dome "rising quickly with a lot of energy beneath the mountain. Because the earthquakes have provided openings for steam and pressure to escape, a major eruption is not expected.
