India, April 15 -- A 5.2-magnitude earthquake struck near Julian in San Diego County on Monday morning, sending tremors across Southern California. The quake originated just south of the Elsinore Fault Zone, a branch of the larger San Andreas fault system. Shaking was felt as far north as Los Angeles, approximately 120 miles from the epicenter.

One of the most talked-about moments from the quake came from the San Diego Zoo Safari Park, where a herd of African elephants reacted instinctively to the tremor. A video, now viral on social media, shows the elephants rushing to shield their young by forming an "alert circle"-a defensive behavior used to protect the most vulnerable members of the herd.

According to the San Diego Zoo Wildlife Al...