Sunset Crater is a

cinder cone A cinder cone or scoria cone is a steep, volcanic cone, conical landform of loose pyroclastic rock, pyroclastic fragments, such as volcanic ash, clinkers, or scoria that has been built around a volcanic vent. The pyroclastic fragments are forme ...

located north of Flagstaff in the U.S. state of

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

. The crater is within the Sunset Crater Volcano National Monument. Sunset Crater is the youngest in a string of

volcanoes A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often fo ...

(the San Francisco volcanic field) that is related to the nearby San Francisco Peaks.

Formation

The date of the eruptions that formed the was initially derived from tree-ring dates, suggesting 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 An eruption column or eruption plume is a cloud of super-heated Volcanic ash, ash and tephra suspended in volcanic gas, gases emitted during an explosive eruption, explosive volcanic eruption. The volcanic materials form a vertical column or Plu ...

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. The volcano has partially revegetated, with

pine A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. ''World Flora Online'' accepts 134 species-rank taxa (119 species and 15 nothospecies) of pines as cu ...

s and

wildflower A wildflower (or wild flower) is a flower that grows in the wild, rather than being intentionally seeded or planted. The term implies that the plant is neither a hybrid nor a selected cultivar that is any different from the native plant, eve ...

s. The crater is the namesake for the Sunset Crater Beardtongue (''Penstemon clutei''). The volcano is monitored by the Yellowstone Volcano Observatory and is classified as a moderate threat. Damage from hikers forced the

National Park Service The National Park Service (NPS) is an List of federal agencies in the United States, agency of the Federal government of the United States, United States federal government, within the US Department of the Interior. The service manages all List ...

to close a trail leading to the crater, but a short trail at the base remains. The hiking trail below the summit skirts the substantial Bonito Lava Flow. This hardened lava is black and appears fresh as it has devastated the forest in its path. The lava flow also created an ice cave or tube that is now closed to the public after a partial collapse.

2015 eruption scare

On June 5, 2015, a website with satellite images reported steam rising from the crater, leading to fears that Sunset Crater was erupting. The cause of the steam was later determined to be a forest fire, and geologists stated that the volcano was extinct.

Sunset Crater Volcano National Monument

Sunset Crater Volcano National Monument is a U.S. national monument created to protect Sunset Crater, a

within the San Francisco Volcanic Field. The monument is managed by the

in conjunction with nearby Wupatki National Monument. In 1928, a Hollywood film company, Famous Players–Lasky Corporation, planned to detonate large quantities of explosives on the side of Sunset Crater in order to create an avalanche for Zane Grey's motion picture ''

Avalanche An avalanche is a rapid flow of snow down a Grade (slope), slope, such as a hill or mountain. Avalanches can be triggered spontaneously, by factors such as increased precipitation or snowpack weakening, or by external means such as humans, othe ...

''. Public outcry over this plan led in part to the proclamation of Sunset Crater Volcano National Monument by President

Herbert Hoover Herbert Clark Hoover (August 10, 1874 – October 20, 1964) was the 31st president of the United States, serving from 1929 to 1933. A wealthy mining engineer before his presidency, Hoover led the wartime Commission for Relief in Belgium and ...

in 1930. A 1-mile (1.6 km), self-guided loop trail is located at the base of Sunset Crater, but hiking to the summit is not permitted. A trail providing access to the summit and crater was closed in 1973 because of excessive erosion caused by hikers. A visitor center is located near the park entrance, north of

Flagstaff, Arizona Flagstaff ( ), known locally as Flag, is the county seat of Coconino County, Arizona, in the southwestern United States. As of the 2020 United States census, the city's population was 76,831. Flagstaff is the principal city of the Coconino Cou ...

, along U.S. Highway 89. In April 2022, the Tunnel Fire burned over the entirety of the monument, though the visitor center was spared. In December 2022, 98 acres including the visitor center and administrative facilities were transferred from Coconino National Forest to the national monument. (incorporated into the Consolidated Appropriations Act, 2023)

Climate

According to the

Köppen Climate Classification The Köppen climate classification divides Earth climates into five main climate groups, with each group being divided based on patterns of seasonal precipitation and temperature. The five main groups are ''A'' (tropical), ''B'' (arid), ''C'' (te ...

system, Sunset Crater has a

Continental climate Continental climates often have a significant annual variation in temperature (warm to hot summers and cold winters). They tend to occur in central and eastern parts of the three northern-tier continents (North America, Europe, and Asia), typi ...

, abbreviated "Dsb" on climate maps.

References

External links

Sunset Crater National Monument
at

Sunset Crater
at

USGS The United States Geological Survey (USGS), founded as the Geological Survey, is an government agency, agency of the United States Department of the Interior, U.S. Department of the Interior whose work spans the disciplines of biology, geograp ...