Listed below are two places in the United States that are
considered "active" volcanic areas.
Mount St Helens
On May 18, 1980, after a long period of rest, this quiet
mountain in Washington provided 
detailed observations on the mechanics
of highly explosive eruptions.
Long Valley
This field seismometer measures earthquakes associated
with subsurface volcanic forces and may help to predict
future events. It sits on a plateau known as the "Volcanic
Tableland" formed by a major eruption 600,000 years ago.
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