The youngest in a string of volcanoes (the San Francisco volcanic field) erupts near the volcanic San Francisco Peaks in northern Arizona around 1085, forming the so-called Sunset Crater, a one thousand-foot-high (three hundred and five meter) cone with a rim of bright red orange ash and cinder.
The eruption produces a blanket of ash and lapilli covering an area of more than twenty-one hundred square kilometers (eight hundred and ten square miles) and forces the temporary abandonment of settlements of the local Sinagua people.
