A new eruptive cycle at Mount St. Helens?



What triggered the recent and ongoing eruption of Mount St. Helens? Is it new magma or just leftovers from the 1980s? How long will the eruption continue? Will the magma composition change, and will it become more explosive?

The U.S. Geological Survey's (USGS) Cascades Volcano Observatory (CVO) hosted a three-day workshop at which 25 petrologists addressed these fundamental questions. The workshop began with a review of monitoring data by CVO staff and was followed by presentations and discussions of new petrologic data.