USGS HOME
Contact USGS

  • About
  • Observatories
  • Activity
  • Education
  • Publications

Overlay represents area within CVO's area of responsibility.
Map Legend
Cascade Range Weekly Update
Friday, October 17, 2014 9:57 AM
 Current Volcano Alert Level: NORMAL
 Current Aviation Color Code: GREEN
 
Cascades Volcano Observatory's mission
The U.S. Geological Survey's Cascades Volcano Observatory strives to serve the national interest by helping people to live knowledgeably and safely with volcanoes in WA, OR, and ID.

HOT STUFF   (archive)
Young Volcanoes in WA, OR & ID1

10th Anniversary of Mount St. Helens Lava-Dome Building Eruption
September 25, 2014

In the early morning hours of September 23, 2004, a swarm of small-magnitude earthquakes about half a mile below Earth's surface marked the reawakening of Mount St. Helens. On October 1, 2004, the first of several small explosions shot a plume of volcanic ash and gases skyward. A growing welt beneath Crater Glacier heralded the rise of semi-solid magma that erupted onto the surface, forming rocky spines, smooth-sided ridges, and jumbled piles of lava over the next 34 months. During the eruption, scientists made important strides in volcano monitoring, developing new tools for investigation and insight into eruptive behavior. View the 2004-2008 Mount St. Helens Eruption video and read about the eruption in the 2004-2008 event timeline and statistics.


Quick Links
Photo Archive
Hot Stuff Archive
Maps and Graphics
Frequently Asked Questions
Glossary
Publications
Hydrology