Sunset Crater National Monument - Arizona Travel

Explore unique volcanic history on our small educational group tours.

Sunset Crater Volcano was born in a series of eruptions near 1065 A.D. making it one of the youngest scoria cones in the contiguous United States. Tremendous seismic activity forever altered the lives of local people and dramatically changed the surrounding area. Lava flows and cinders still look as if they were only created yesterday. Among these dramatic geologic features, you'll find life returning as trees, wildflowers, and signs of wildlife reappear. Sunset Crater was named by John Wesley Powell, first director of the U.S. Geological Survey, for the topmost cap of oxidized, red rocks which makes it appear to constantly be swathed in the light of the sunset. The colors at the top of the cone are silica, gypsum, and iron oxide that formed from fumaroles. Sunset Crater is a nearly symmetrical cone made of dark-gray scoria, which is a porous rock made of volcanic glass fragments, and scattered bombs. The cone is about 1,000 feet high and 1 mile in base diameter.  

The Bonito Lava Flow is one of several flows that streamed out from the base of Sunset Crater Volcano about 930 years ago. The lava flow erupted from the west and northwest base of the cone and covered an area of 1.8 square miles. The 2200° Fahrenheit liquid formed a river of black lava that poured over the landscape before it solidified. The eruption at Sunset Crater covered an area of 800 square miles with lapilli and ash. The eruption was strombolian in style and large, with eruption columns several hundred feet high. The Kana-a lava flow was erupted from the base of the east side of the cone and traveled 6 miles down a wash. The Sunset eruption was unusual because of the volume of volcanic products (about 0.7 cubic miles) is large for a strombolian event, the air fall dispersal was large, and the discharge rate for magma was high.