When erupting, all volcanoes pose a degree of risk to people and infrastructure, however, the risks are not equivalent from one volcano to another because of differences in eruptive style and geographic location. Assessing the relative threats posed by U.S. volcanoes identifies which volcanoes warrant the greatest risk-mitigation efforts by the U.S. Geological Survey and its partners. This update
San Francisco Volcanic Field
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Northern Arizona's San Francisco Volcanic Field, which covers about 4,700 square kilometers (1,800 square miles), is an area of young volcanoes along the southern margin of the Colorado Plateau. Much of the field lies within Coconino and Kaibab National Forests.
Location: Arizona, Coconino County
Latitude: 35.37° N
Longitude: 111.5° W
Elevation: 2,447 (m) 8,028 (f)
Volcano type: volcanic field
Most recent eruption: 1085 A.D.
Nearby towns: Flagstaff, Williams
Threat Potential: Moderate*
*based on the National Volcano Early Warning System
Northern Arizona's San Francisco Volcanic Field, which covers about 4,700 km2 (1,800 mi2), is an area of young volcanoes along the southern margin of the Colorado Plateau. Much of the field lies within Coconino and Kaibab National Forests. During its approximately 6-million-year history, this field has produced more than 600 volcanoes, and almost all of the hills and mountains between Flagstaff and the Grand Canyon are representative of the San Francisco Volcanic Field. The most prominent landmark is San Francisco Mountain, a stratovolcano that rises to 3,850 m (12,633 ft) and serves as a scenic backdrop to the city of Flagstaff. Sunset Crater, the State's youngest volcano, erupted in about A.D. 1085 and must have been witnessed by native inhabitants who lived very nearby. Sunset Crater Volcano National Monument was founded in 1930 to protect the cinder cone and associated lava flow.