How likely are we to have a volcano explosion in Arizona? How would you like to visit a volcano in Arizona?
Remember the towering mountain in The Lord of the Rings, filmed in New Zealand? Known as Tongariro, on August 6, it erupted, sending a plume of ash 20,000 feet into the air. Falling ash showered the North Island, disrupting domestic air travel. The volcano had been dormant for nearly one hundred years prior to last week’s eruption.
Is the danger of eruption now over? GNS scientists have discovered elevated levels in volcanic gases, suggesting that magma is accumulating beneath the volcano. Therefore, New Zealand may have an occurrence similar to Mount. St. Helens here in America in 1980. That volcano had not seen volcanic activity since the mid-1800s.
Does Tucson and Arizona have dormant volcanoes? Interestingly, the whole Tucson area is scattered with former volcanoes, big and small. Necks, solid formations formed as magma rises in a cone that later cooled, then left behind after the soft deposits eroded, can be found in many places if you know how to look for them. Picacho Peak was thought to be a volcano neck, but it is not.
The Catalina Mountains, to the north, are the result of volcanic action and a volcano, 70 million years ago. Later geologic action caused the top of that volcano to break loose and slide 20 miles west, forming the Tucson Mountains. Find more details, and an interactive illustration.
Sentinel Peak ,or “A” Mountain, shows different layers of volcanic ash and lava, but it is not a volcano, but the side slope remains of one or more, larger volcanoes.
The volcano map does not show any signs of probable renewed activity close to Tucson. However, south-east of Tucson, the San Bernardino volcanic field still has hot springs, testifying to lingering heat in the subsurface. 130 vents form the San Bernardino field, mostly cinder cones. The most prominent vent is Paramore Crater, nearly one-mile in diameter and 200 feet deep. The hot springs remain even though the field was active between 1 million and 27,000 years ago.
The most famous and most recently active volcano in Arizona is Sunset Crater near Flagstaff, which erupted less than 1,000 years ago and has been a National Monument since 1930.
In their fact sheet, Priest, Duffield, Malis-Clark, Hendley II, and Stauffer explain that “all hills and mountains between Flagstaff and the Grand Canyon are geologically young but extinct volcanoes of the San Francisco Volcanic Field.” U.S. Geological Survey (USGS) scientists believe it is likely that eruptions will occur again in the San Francisco Volcanic Field. The average interval between periods of volcanic activity is several thousand years. However, it is impossible to forecast when the next eruption will occur.
The USGS provides more information on volcanoes, and easy to read classifications of magma, including ash, “bombs“, and lava. For instance, avalanches and mudflows cause more damage than the volcano.
For fun answers and information to the question: If volcanoes cause diamonds, how come Arizona has no diamonds? Check Clay Thompson’s blog. The simple answer, volcanoes need carbon to form diamonds. Not all volcanoes have carbon.
So, interest your child in news of volcanoes. Take a field trip up “A” mountain to observe the different layers of ash, seen in the road cuts. Near the big “A” and on top, places can be found of hard, flattish, black rock, where lava flowed. The white rock is not magma, but caliche – a calcium deposit.
Take a trip to Sunset Crater National Park to see our most recent volcano. Remember, the trails there are wheelchair accessible. Make learning live. Make it outdoors. Make it fun.