The Ml 2.7 earthquake near Patterson was the strongest within 30 km of this epicenter
in the past 2 years. The previous largest was a Ml 3.5 on March 14, 1999.
Two moderate sized earthquakes have been recorded in this area. A Ml 6.0 occurred
on April 10, 1881 and a Ml 5.5 occurred on Oct 14, 1998. The later was about 20
km north of today's epicenter, so this event may be related to that one.
Our database shows 102 events in this area of Ml 2.5 or greater since the late
1800's. The last event of Ml>=2 occurred in Sept. 2000 (Ml 2.0)