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Sunset Crater
"Sunset Crater, named for its brilliantly colored scoria deposits mantling the cone, is the youngest of the more than 550 vents of the vast San Francisco volcanic field in northern Arizona. The eruptions forming the 340-m-high Sunset Crater cinder cone were initially considered from tree-ring dating to have begun between the growing seasons of 1064-1065 AD; however, more recent paleomagnetic evidence places the onset of the eruption sometime between about 1080 and 1150 AD. The largest vent of the eruption, Sunset Crater itself, was the source of the Bonito and Kana-a lava flows that extended about 2.5 km NW and 9.6 km NE, respectively. Additional vents along a 10-km-long fissure extending SE produced small spatter ramparts and a 6.4-km-long lava flow to the east. The Sunset Crater eruption produced a blanket of ash and lapilli covering an area of more than 2100 sq km and forced the abandonment of settlements of the indigenous Sinagua Indians."  -Smithsonian Volcano Archive
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