SOUTHERN California has been rocked by a 4.2 magnitude earthquake that shook buildings throughout the region. San Diego residents flooded social media with reports of the quake, which was also felt in neighboring Orange and Riverside counties. 2 An earthquake hit San Diego County on Friday, shaking buildings with a 4.2 tremor Credit: U.S. Geological Survey2 A map from U.S. Geological Survey shows reports from people who felt the earthquake Credit: U.S. Geological SurveyThe quake hit near the Palomar Observatory, which is located roughly 65 miles from downtown San Diego. “The dogs were freaked out - they ran around barking at it.”The U.S. Geological Survey initially reported that the quake was an estimated 4.5 but later dropped the magnitude to 4.2. The National Weather Service in San Diego confirmed the quake, adding that two jolts were felt at the office.