Shaking was reported in communities east of Los Angeles due to a magnitude-3.1 earthquake in Ontario. The quake with a depth of about 3.5 miles was reported at 12:56 p.m. Earthquakes Sep 16 Seismologist Dr. Lucy Jones says this is most important to remember when earthquake strikes Southern California Aug 31 Series of earthquakes shake SoCal: Are we prepared for ‘the big one'? Weak to light shaking was reported in Ontario, Rancho Cucamonga, Fontana, Upland, Riverside and other areas. Smaller quakes, ranging in magnitude from 1.0 to 1.8, were reported within an hour of the magnitude-3.1 earthquake. Those were centered near Ontario, Corona and Home Gardens. Refresh this page for updates.