Seismologist Lucy Jones speaks at a media briefing at the Caltech Seismological Laboratory in Pasadena, California following the 6.4 Searles earthquake near Ridgecrest about 150 miles (241km) north of Los Angeles, July 4, 2019. - Southern California was rocked by a 6.4-magnitude earthquake Thursday morning, the US Geological Survey said, with authorities warning that the temblor, the largest in two decades, might not be the day's last. (Photo by Robyn Beck / AFP)