Volcano Hazards Program

U.S. Geological Survey
Fact Sheet 2006-3139
Version 1.0

U.S. Geological Survey’s Alert Notification System for Volcanic Activity

By Cynthia A. Gardner and Marianne C. Guffanti


screenshot of first page showing map of northern Pacific and volcanic areas

The United States and its territories have about 170 volcanoes that have been active during the past 10,000 years, and most could erupt again in the future. In the past 500 years, 80 U.S. volcanoes have erupted one or more times. About 50 of these recently active volcanoes are monitored, although not all to the same degree. Through its five volcano observatories, the U.S. Geological Survey (USGS) issues information and warnings to the public about volcanic activity. For clarity of warnings during volcanic crises, the USGS has now standardized the alert-notification system used at its observatories.

Download this report as a four-page PDF document (fs2006-3139.pdf; 2.8 MB)

For questions about the content of this report, contact Cynthia Gardner

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