A magnitude 3.6 earthquake was felt from the Chino Valley to Winslow and as far south as Phoenix. The quake occurred at 11:20 a.m. local time today, 18 miles NNW of Prescott. [right, location map of quake - star - with historical quakes shown as small orange dots. Credit, USGS]
As of 8 pm tonight, 540 people have reported they felt the event on the USGS website.
The area has had little historical seismic activity.
update 10-16: The Prescott Courier reports that the magnitude is revised to 3.2 and the location based on additional analysis by Dr. David Brumbaugh at the Arizona Earthquake Information Center at Northern Arizona University.