M5 Earthquake in Eastern Arizona last night (June 28, 2014)

This is quite interesting and unusual historically. There was an earthquake in SE Arizona near the New Mexico border at about 10 pm local time. Here are a few links:

1. USGS site on the event
2. USGS site Did You Feel It shows that it was widely and lightly felt across southeastern Arizona and southwestern New Mexico
3. TUC vertical long period seismogram from Tucson show the event and aftershocks
4. Arizona earthquake history from AEIC does not show a lot of activity historically there
5. AZ Oil and Gas information I wonder if associated with oil and gas activities? AZ Is Hydraulic Fracturing a Threat in Arizona? (from AZGS).

Normal fault focal mechanism with roughly N-S striking planes is generally consistent with the few active faults in the area (USGS QFaults; see also AZGS fault map). I will post more when I have some more time.