Calderas – the supervolcanoes of the USA and beyond

Valles Caldera and Toledo Caldera in north-central New Mexico – Source:

While there are calderas (supervolcanoes) all over the planet, this post will concentrate on those found in the United States. These enormous volcanoes are formed in one of two (2) manners:

• after an explosive eruption; or
• when the inside of the volcano collapses after the magma chamber is emptied.

Inside Valles Caldera (September 2019) with the resurgent dome visible to the left.

To differentiate between a caldera and a crater, the following criteria is used by the USGS:

“The size of the depression governs whether we call the geographic feature a caldera or a crater. In general, if a feature is larger than 1.6 kilometers (1.0 miles) in diameter, we call it a caldera, and, if it is smaller, a crater.”

SOURCE: USGS

Aniakchak Caldera – Source: volcanoes.usgs.gov

Image shows example(s) of new calderas that formed within older/larger ones – Source: USGS.gov

Here’s a list of the identified calderas located within the United States:

• Aniakchak Caldera: Aniakchak National Monument and Preserve, Alaska = 6.4 miles in diameter – partially lake-filled caldera
• Bachelor Caldera: Colorado = 9.3 miles by 15.5 miles – – formed adjacent to the La Garita Caldera
• Big Cottonwood Caldera: Nevada = approximately 9.3 miles in diameter
• Blue Creek Caldera: Idaho= 34.2 miles by 18.6 miles
• Bonanza Caldera: Colorado
• Bruneau-Jarbidge Caldera: Idaho
• Cochetopa Park Caldera: Colorado = approximately 12.4 miles in diameter
• Crater Lake Caldera on Mount Mazama: Crater Lake National Park, Oregon = 5 miles long by 6 miles wide lake-filled caldera
• Creede Caldera: Colorado = approximately 7.8 miles in diameter
• Crooked River Caldera: Oregon= 25 miles by 17 miles
• Fisher Caldera: Alaska = 6.8 miles by 11 miles
• Herbert Volcano Caldera: Alaska = 1.2 miles in diameter
• Henry’s Fork Caldera: Idaho = 18 miles by 23 miles
• Island Park Caldera: Idaho and Wyoming = 49.7 miles by 40.4 miles
• Kilauea Caldera: Hawaii = 2.9 miles by 2 miles
• Kulshan Caldera: northeast of Mt. Baker, Washington – largely filled in
• Lake City Caldera: Colorado = 7.5 miles by 9.3 miles – formed with the larger/older Uncompahgre Caldera
• La Garita Caldera: Colorado – 21.8 miles by 46.6 miles – floor is buried
• Long Valley Caldera: California = 20 miles by 11 miles
• Lost Lakes Caldera: Colorado – buried
• Mahogany Mountain Caldera: Oregon = 12.4 miles by 9.3 miles
• Makushin Volcano Caldera: Alaska = 1.6 miles by 1.9 miles
• Marshall Creek Caldera: Colorado
• Masonic Park Caldera: Colorado
• McDermitt Caldera: Oregon and Nevada = 28 miles by 22 miles
• Medicine Lake Volcano: California = 4.3 miles by 7.5 miles
• Moku’aweoweo Caldera on Mauna Loa: Hawaii = 4 miles by 1.6 miles
• Mount Emmons Caldera: Alaska = 7 miles by 11 miles
• Mount Hope Caldera: Colorado – mostly buried
• Mount Kaguyak Caldera: Alaska = 1.6 mile diameter lake-filled caldera
• Mount Katmai Caldera: Alaska = 1.9 miles by 2.5 miles
• Mount Okmok Caldera: Alaska = 9.3 miles in diameter
• Mount Spurr Caldera: Alaska = 3.1 miles in diameter
• Mount Veniaminof Caldera: Alaska = 5 miles by 6.8 miles – glacier filled caldera
• Newberry Volcano: Newberry National Volcanic Monument, Oregon = 75 miles long by 23 miles wide
• North Pass Caldera: Colorado
• Platoro Caldera: Colorado = 12.4 miles in diameter
• San Juan Caldera: Colorado = approximately 10 miles in diameter
• San Luis Caldera: Colorado = approximately 7.8 miles in diameter
• Silverton Caldera: Colorado =approximately 7.8 miles in diameter – formed within the larger/older San Juan Caldera
• South River Caldera: Colorado
• Summitville Caldera: Colorado = approximately 6.2 miles in diameter – formed within the larger/older Platoro Caldera
• Three Fingers Caldera: Oregon = 10 miles by 8.1 miles
• Toledo Caldera: New Mexico = 5.8 miles in diameter – formed adjacent to the larger/older Valles Caldera
• Tower Mountain Caldera: Oregon = 8.7 miles in diameter
• Twin Peaks Caldera: Idaho = 12.4 miles in diameter
• Uncompahgre Caldera: Colorado = approximately 9.3 miles by 6.2 miles
• Ute Creek Caldera: Colorado – only partially visible
• Valles Caldera: Valles Caldera National Preserve, New Mexico = 13.7 miles in diameter
• Virgin Valley Caldera: Nevada = 14 miles in diameter
• Wildcat Mountain Caldera: Oregon = 10 miles by 6.8 miles
• Yellowstone Caldera: Wyoming = 43 miles by 28 miles

Valles Caldera from adjacent 10,200′ Cerro Grande – November 2021.

SOURCES:

• https://en.wikipedia.org/wiki/Caldera
• en.wikipedia.org for each caldera
• https://geology.com/articles/caldera/
• https://www.nationalgeographic.org/encyclopedia/calderas/
• https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/JB091iB02p01799
• https://pubs.usgs.gov/imap/i2799/data/pdf/i2799pamphlet.pdf
• https://en.wikipedia.org/wiki/San_Juan_volcanic_field
• https://en.wikipedia.org/wiki/Cochetopa_Dome
• https://pubs.er.usgs.gov/publication/70161990
• https://pubs.usgs.gov/journal/1973/vol1issue6/report.pdf
• https://pubs.usgs.gov/pp/0958/report.pdf
• https://en.wikipedia.org/wiki/Fisher_Caldera
• https://en.wikipedia.org/wiki/Category:Calderas_of_Alaska
• https://volcano.si.edu/volcano.cfm?vn=312070
• https://en.wikipedia.org/wiki/Bruneau-Jarbidge_caldera
• https://www.oregongeology.org/pubs/og/OGv69n01-CrookedRivercaldera.pdf
• https://volcano.oregonstate.edu/hawiian-calderas
• https://en.wikipedia.org/wiki/Kīlauea_Caldera
• https://www.usgs.gov/center-news/volcano-watch-when-did-mokuaweoweo-summit-caldera-mauna-loa-form
• https://volcanoes.usgs.gov/vsc/glossary/caldera.html
• https://en.wikipedia.org/wiki/Kulshan_Caldera