Overlay represents area within CVO's area of responsibility.
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.
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.
CVO Scientists to Participate in Classroom Webinars
September 23, 2014
Since 2008, the Mount St. Helens Institute has brought live, interactive video presentations to students across the country. This fall, CVO scientists are featured:
- On September 26, Cynthia Gardner will talk about Mount St. Helens, how volcanoes reawaken, where magma is stored, and the many ways volcanoes erupt;
- On October 24, Seth Moran will discuss the various processes that cause earthquakes beneath volcanoes and how seismologists use seismicity to "diagnose" volcanic activity;
- On November 21, Dan Dzurisin will describe how changes on the surface of a volcano tell us something about what is going on deep inside the Earth.
The presentations are designed for 5th–8th grades. Participating classes will be able to write questions using the "chat" feature and time will be reserved to address student questions. Visit Mount St. Helens Institute Volcano Explorers
to see the type of equipment needed and to register for the free program.
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