I participated in a tour of one of our very popular local attractions, and at one point the tour guide mentioned to the group that there is no seismic activity in Arizona. I knew that it wasn't true!
One of the reasons so many people come to live in Arizona is because there are few natural disasters. Once they have lived through floods, tornadoes, hurricanes and California earthquakes they tend to seek out a location where they are less likely to have to evacuate their homes every other year.
Although earthquakes are rare in Arizona, and when they occur there usually isn't any devastation, they do happen. Earthquakes of a magnitude of between 2 and 3 are fairly common, mostly in the northern half of the state. On May 9, 2009 a 3.1 magnitude earthquake occurred near Cordes Lakes, Arizona. That's just about 80 miles from downtown Phoenix. In 1976 there was a 4.9 magnitude earthquake in Chino Valley, about 100 miles north of Phoenix.
Bottom line: The statement that there is no seismic activity in Arizona is false. It is a myth. We do have earthquakes in Arizona, but they rarely, if ever, result in damage or injuries.