Geology Reference
In-Depth Information
Exercise 4 • Volcanoes and Volcanic Hazards
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FIGURE 4.4
This map shows the location, time, and type of volcanic eruptions in the Long Valley area over the past 5,000 years.
Steam blasts are also known as phreatic (pronounced "free-attic") eruptions, and are created when hot waters explode to steam. They
do not involve the eruption of new magma. Explosive eruptions include both relatively small pyroclastic eruptions that extend about 5
miles from their vents, and tephra eruptions. (US Geological Survey, Long Valley Observatory)
