A magnitude 4.2 earthquake occurred about 25 miles southeast of Mexicali at 8:19 pm tonight. There are no reports from local communities yet but I expect it could have been at least felt in Yuma and other communities.
Update 4-12-09 8am: the event is recorded on the stations of the new Arizona Integrated Seismic Network. The Wintersburg AZ station shows the event on the 2:00-4:00 am GMT time line at left.