The date of the eruptions that formed the was initially calculated using
tree-ring dates, which suggested that the eruption began between the growing seasons of AD 1064–1065. However, more recent geologic and archaeological evidence places the eruption around AD 1085. The largest vent of the eruption, Sunset Crater itself, was the source of the Bonito and Kana-a lava flows that extended about northwest and northeast, respectively. Additional vents along a extending southeast produced small
spatter ramparts and a to the east. The Sunset Crater eruption peaked at
VEI 4 (Sub-
Plinian), produced a total of 0.52 km3 of ejecta, had an
eruption column between 20-30km tall and produced a blanket of ash and
lapilli covering an area of more than , which forced the temporary abandonment of settlements of the local
Sinagua people. ==Current condition==