A preliminary 2.6 magnitude earthquake struck near San Ramon Saturday morning, according to the United States Geological Survey. The quake, which hit at around 8:10 a.m., was centered just south of San Ramon, the USGS said. This follows a series of earthquakes registered in the same area on Fr iday evening, including a 4.0 magnitude quake. 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