This
volcanic cinder cone with summit crater was formed just before
1100 AD. Its upper portion is colored as if by a sunset. Sunset
Crater appeared when molten rock was ejected into the air from a
small crack in the Earth's crust. When this material fell to the
ground, it was already solid and came down as large bombs and
smaller cinders. This volcanic activity continued over 200 years
building and re-shaping the cone and eventually creating a
1,000-foot cinder cone volcano around the vent. An 800 square
mile radius was dusted with ash from this volcano. Lava flowed
from the fissure both in 1064 and again in 1180. Over time new
gas vents opened up forming spatter cones around the main cinder
cone. In a final burst of activity, around 1250, lava containing
iron and sulfur shot out of the vent. This lava then oxidized
red and yellow, these colors painting the crater with a
permanent "sunset" so bright that it appears still to
glow from intense inner heat.
The
Monument is reached by a side road off US 89 16 miles north of
Flagstaff; this road also passes through the Wupatki National
Monument before rejoining US 89 15 miles further north. Payment
is $5 for private cars, made at the visitor center near the
entrance - the fee gives access to both Monuments. There are
interesting exhibits about volcanism, and a seismograph which
continually monitors earthquake activity around the world. The
road at this point passes pine woodland with flower-filled
meadows and distant volcanic hills.
This
volcanic cinder cone with summit crater was formed just before
1100 AD. Its upper portion is colored as if by a sunset. Sunset
Crater appeared when molten rock was ejected into the air from a
small crack in the Earth's crust. When this material fell to the
ground, it was already solid and came down as large bombs and
smaller cinders. This volcanic activity continued over 200 years
building and re-shaping the cone and eventually creating a
1,000-foot cinder cone volcano around the vent. An 800 square
mile radius was dusted with ash from this volcano. Lava flowed
from the fissure both in 1064 and again in 1180. Over time new
gas vents opened up forming spatter cones around the main cinder
cone. In a final burst of activity, around 1250, lava containing
iron and sulfur shot out of the vent. This lava then oxidized
red and yellow, these colors painting the crater with a
permanent "sunset" so bright that it appears still to
glow from intense inner heat.
The
Monument is reached by a side road off US 89 16 miles north of
Flagstaff; this road also passes through the Wupatki National
Monument before rejoining US 89 15 miles further north. Payment
is $5 for private cars, made at the visitor center near the
entrance - the fee gives access to both Monuments. There are
interesting exhibits about volcanism, and a seismograph which
continually monitors earthquake activity around the world. The
road at this point passes pine woodland with flower-filled
meadows and distant volcanic hills.