An earthquake measuring 4.5 on Richter scale had hit Bay Area in California in the United States. An earthquake measuring 4.5 on the Richter scale struck Bay Area in California, US: USGS — ANI (@ANI) January 4, 2018 × The earthquake struck at 2:39 am. It shook San Francisco Bay Area residents out of their slumber. According to the US Geological Survey, the quake's epicenter was 2 miles away from Berkeley, California. There were no reports of any casualty.