At  21:26 hrs PDT this evening, June 14, 2010, a Mw 5.7 earthquake occurred  5 miles southeast of the Imperial County community of Ocotillo.  The earthquake was the largest aftershock so far of the Mw 7.2 El Mayor-Cucapah earthquake that occurred on Easter Sunday. This earthquake occurred at the northern end of the aftershock zone in an area where there has been considerable activity during the past 10 weeks.  The Mw 5.7 earthquake rapidly was followed by a tight cluster of over 30 smaller earthquakes, about 20 of which were in the range of Mw 3.0 to 4.5.

CEPEC convened a teleconference call at 22:30 hrs PDT to discuss the implications of the aftershock.  It occurred along the southernmost portion of the Elsinore Fault Zone, which has not had a major earthquake in the past 100 years or so.  Because of the location of the Mw 5.7 aftershock , CEPEC believes that the probability of a larger event on the Elsinore Fault or the San Jacinto Fault has increased considerably, and will remain so for several days, although the absolute probability remains low, on the order of one percent.  CEPEC will continue to monitor the situation.

--Statement by the California Earthquake Prediction Evaluation Council sent to the California Emergency Management Agency at 12:04 am, June 15, 2010.

See: http://earthquake.usgs.gov/earthquakes/recenteqsus/Quakes/ci14745580.php