Measuring Mt. Rainier.
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Image from: U.S. Geological Survey, photo by Lyn Topinka
This image shows a volcanologist monitoring the changing shape of Mt. Rainier in Washington. Volcanologists often use lasers to perform these measurements.
Volcanologist look for any changes in volcanoes, from small earthquakes to shape changes to melting snow. Any of these changes might be a sign that a volcano is becoming active.
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