A series of earthquakes, including a 4.0 magnitude earthquake, struck near San Ramon Saturday afternoon, according to the United States Geological Survey. The first quake, which hit at around 6:30 p.m., was centered just south of San Ramon, the USGS said. The USGS had previously registered it as magnitude 3.9, but it later upgraded it to magnitude 4.0. A few minutes later, a 2.8 magnitude earthquake followed by a 3.0 magnitude earthquake also hit the area, according to the USGS. This follows a series of earthquakes registered in the same area on Friday evening, including a 4.0 magnitude quake, as well as a 2.6 magnitude earthquake registered on Saturday morning. 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