A 4.3 magnitude earthquake struck 15 miles north of Healdsburg, according to the United States Geological Survey. The quake, which hit at 9:22 a.m. Saturday, was centered in the Geysers area, the USGS said. The Geysers is an area known for producing many earthquakes. The earthquake was initial ly reported by the USGS as having a 3.9 magnitude. Several smaller aftershocks followed. 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