Monday, December 01, 2014

Magnitude 4.7 earthquake rocks Sedona-Flagstaff area

 AZGS released the following statement this afternoon:

A magnitude (M) 4.7 earthquake shook Sedona and Flagstaff in Sunday evening. The event occurred at 10:57 p.m. about 7 miles north of Sedona, near Munds Park.

The earthquake and smaller aftershocks are shallow, with depths estimated at 1.3 miles. More than 1,100 people reported feeling the event to the U.S. Geological Survey's, "Did you feel it," online forum at

One individual from near the Village of Oak Creek said, "It rocked my desk chair (on casters) back and forth, shook windows, and caused my mac desktop to tremble as well as the desk lamp... ."

According to Phil Pearthree, Chief of Environmental Geology at the Arizona Geological Survey, "the location is quite close to the Oak Creek fault zone, a down-to-the-east normal fault with 700 feet of vertical displacement in the past 10 million years or so. We think this fault has been active in the past 2 million years, but don't know how recently it has ruptured in a large earthquake."

Using the Arizona Integrated Seismic Network to track seismic events, AZGS geologist Jeri Young identified at least 10 aftershocks, three of which approach M 3.0. See the attached map for two aftershocks: M 2.2 at 12:10 a.m. and an M 3.0 at 12:53 a.m. (MST). On Nov. 25, 2014, an M 3.5 event occurred proximal to last night's earthquake.

Both Denny Foulk, Yavapai County Emergency Manager, and Rob Rowley, Coconino County Emergency Manager, confirmed that there were no reports of damage to homes or roads. There was one minor rock fall in Oak Creek Canyon that was rapidly cleared.

The largest historical earthquakes in the region, a series of three M 6.0 events, occurred between 1906 and 1912, near Flagstaff. More recently, a M 5.1 earthquake occurred in 2005 about 50 miles southwest of this epicenter, and a M3.5 earthquake occurred very close to this epicenter last week (Nov. 25,2014).

Historical earthquake activity for all of Arizona is available online at the interactive Natural Hazards in Arizona Viewer.

For additional information and updates contact the Arizona Geological Survey or follow us at our social media information outlets:

Arizona Geology Blog

Arizona Geological Survey Facebook

Arizona Geological Survey Twitter

Arizona Geological Survey Web

Online Resources. The Arizona Geological Survey hosts a number of online resources relevant to earthquakes and earthquake hazards in Arizona:

• Natural Hazards in Arizona Active Faults | Earthquake Epicenters themes

• Earthquakes in Arizona 1852-2011 - Time lapse video showing locations and magnitudes of earthquake events in Arizona. Length: 90 seconds.

• Arizona is Earthquake Country - Forty-four page primer on earthquakes, earthquake hazards and mitigation in Arizona.

• AzEIN - Earthquake Preparedness page from Arizona Emergency Information Network.

[AZGS news release.  12-1-14 2:00 p.m.]

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