Could volcanoes reawaken in Arizona?
Only in Arizona: Now-dormant, but not extinct, the state's volcanic fields likely to reawaken at some point
- Arizona has volcanic fields spread all over the state
- The last major eruption was about 1,000 years ago at Sunset Crater
- The recurrence interval for some of Arizona's volcanoes is on the order of a few thousands of years
The rumbling under your desk may not be the light rail passing by or your stomach telling you to go to In-N-Out Burger.
No, the ground continually shifts under Arizona, along with other states with volcanoes, a reminder that the Earth is, indeed, alive.
But before you run for the hills, arm yourself with some context.
Twenty states claim active, dormant and extinct volcanoes, including neighboring California, Nevada, New Mexico, Colorado and Utah. Arizona's are currently dormant, which means they're not active but have the capability to blow their tops.
Our volcanic past
Traces of our active volcanic past dot the Arizona landscape like spots on a dalmatian, with distinct volcanic fields near Flagstaff, north of Kingman, southwest of Phoenix, east of Douglas, along the Mexico border, and near Show Low in the northeast part of the state.
The last major eruption was about 1,000 years ago at Sunset Crater, about 20 miles northeast of Flagstaff. About the same time, there was another eruption near the north rim of The Grand Canyon in the Uinkaret volcanic field.
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“It would be remarkable if there were no more eruptions at either Sunset (Crater) in the San Francisco volcanic field and Little Springs in the Uinkaret volcanic field,” says Michael Ort of Northern Arizona University and the state's leading volcano expert. “These fields are dormant (not currently erupting), but the recurrence interval is on the order of a few thousands of years. The most likely area for a new eruption in the San Francisco volcanic field would be to the northeast of Sunset.”
Remember that when you try to beat the heat this summer — it could get extra hot as you hike Humphrey's Peak.
Retreat
That's how the Native Americans felt as they farmed the fertile land near Sunset Crater around 1084 A.D., Ort says. They were forced to retreat from the hot cinders and poisonous gases of Sunset Crater and re-establish themselves further south at population centers like Wupatki and perhaps Walnut Canyon.
Remnants of those populations remain today, including impressive pueblo homes, which are now part of the National Park Service.
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“The cinders made a nice mulch that made it possible to farm at lower elevations,” Ort says.
Perhaps we need to add a sixth “C” to the state's five hallmarks — cinders or cones.
Contact “Only in Arizona” columnist Mark Nothaft at marknothaft.onlyinaz@gmail.com. Send him the weird and fun facts and places found #OnlyInArizona.
Volcano Vocabulary
• Active volcano — A currently erupting or recently erupted volcano.
• Caldera — A large basin-shaped volcanic depression with a diameter many times larger than included volcanic vents.
• Cinder cone — A conical hill formed by accumulation of solidified fragments of lava that fall around the vent. Common to Arizona.
• Dormant volcano — Not a currently active volcano, but capable of erupting.
• Extinct volcano — No longer active.
• Magma — Molten rock below the Earth's surface.
• Vent — An opening at the top or side of a volcano where gas, ash or lava may release.
SOURCE: U.S. Geological Survey