A 3.1 magnitude earthquake hit Flagstaff Sunday afternoon, according to the United States Geological Survey.
USGS registered the quake at 2:31 p.m. near Walnut Canyon east of Flagstaff. According to Ryan Porter, assistant professor at the school of earth sciences and environmental sustainability at Northern Arizona University, the quake lasted about 20 seconds — a figure that was measured by a seismometer off Highway 180.
The earthquake was felt in Flagstaff and as far as Sedona and Cottonwood, though only very mildly, according to data submitted to USGS by residents.
“For larger earthquakes, the USGS predicts groundshaking but this was small enough to not make that threshold.” Porter said.
NAU, the Arizona Geological Survey (AZGS) and USGS run survey networks that measure how strong earthquakes are—there are 25 distributed across Northern Arizona, according to Porter—and are located in spots including Fort Valley Road, Wupatki National Monument, Grand Canyon and two near Camp Verde.
Earthquakes are not a new phenomenon in Arizona; far from it, according to Michael Conway, senior research scientist at AZGS.
"It turns out Arizona is earthquake country,'' Conway told Capitol Media Services in an Oct. 15 article. “ … about 100 events a year within the state’s borders.”
Those quakes are usually not felt, however the potential for a magnitude 6 or 7 is possible.
“Usually an earthquake has to reach a magnitude of 4.5 before it causes any damage,” Porter said. He explained that a 4.1 magnitude earthquake along the Oak Creek fault caused minor damage in 2014.
In 1900s, Flagstaff residents were subjected to a magnitude 6.2 quake that toppled several clock towers and caused plaster to crumble off buildings. This event was followed by two more magnitude 6 quakes within the span of six months.