TEMPE, Ariz. (AP) — Most people would think earthquakes are rare in Arizona. But a new study published by Arizona State University researchers found nearly 1,000 earthquakes rattling the state over a three-year period.
A graduate student in ASU's School of Earth and Space Exploration used new seismic data collected as part of the EarthScope project to develop methods to detect and locate small-magnitude earthquakes across Arizona.
EarthScope's USArray Transportable Array was deployed from April 2006 to March 2009 and provided the first opportunity to examine seismicity on a statewide scale.
Of the almost 1,000 earthquakes during the three-year period, the study says 91 percent of them were "microquakes" with a magnitude of 2.0 or smaller which aren't usually felt by people. However, magnitude 4.9 and 5.3 earthquakes occurred in recent years near Flagstaff.