Arizona Geological Survey at the University of Arizona,
A brief overview of the eruptive history of Mount St. Helens’, from the onset of volcanic activity about 272,000 years ago to…
A brief overview of the eruptive history of Mount St. Helens’, from the onset of volcanic activity about 272,000 years ago to…
An eruption 43 years ago dramatically altered the landscape at Mount St. Helens. But that was just one of many changes. This…