Yes, Arizona has two active volcanic fields, and they’re of a type that is monitored by the Yellowstone Volcano Observatory for very good reasons.
San Francisco Volcanic Field
Threat level: Moderate.
Those 16th-century Franciscan monks got around. (Of note, in Spanish times the Californian city that we call San Francisco was known as Yerba Buena.)
You might recognize this place as Sunset Crater National Monument, but it’s also one of at least thirteen monogenetic volcanic fields in the US National Park System.
Here is a two-part series that is 13 years old. The first video needs a few notes:
- Per the Global Volcanism Program, ” The eruptions forming the 340-m-high Sunset Crater cinder cone were initially considered from tree-ring dating to have begun between the growing seasons of 1064-1065 CE; however, more recent paleomagnetic evidence places the activity between about 1080 and 1150 CE.”
- More information about the strong cultural effects of the field in Native American life and lore.
- After the eruption.
- It’s not necessarily a Hawaiian-style hot spot. The asthenosphere in this complex geological part of the US circulates a bit closer to the surface, too.
Now, who wants to explore volcanoes with a geologist?
Uinkaret Volcanic Field
Threat level: Low to very low.
Here is all you need to know about this monogenetic field: It’s. In. The. Grand. Canyon.
And extends northward.
Yes, people interacted with it:
Both the National Park Service and the US Geological Survey are watching these and other western volcanic fields closely for signs that something like this will once again occur in the region:
Here is more on Paricutin’s eruption in a monogenetic volcanic field near Mexico City.
Featured image: Tim Roberts Photography/Shutterstock