A preliminary 2.9 magnitude earthquake struck Saturday afternoon near San Ramon in Contra Costa County, according to the United States Geological Survey. The temblor was reported just before 2 p.m., and was centered about 2.5 miles east of San Ramon, the USGS said. Further information was not immediately available. This is a developing story. Details may change as more information becomes available. Stay tuned for updates. BAY AREA QUAKE CENTRAL You can take steps to plan and prepare for the next big one. Access our Bay Area Quake Tracker, the latest earthquake stories, extensive quake prep checklists, videos and many other disaster preparedness resources all in one place: NBCBAYAREA.COM/QUAKES ...read more read less