Measuring Movement from the Ridgecrest Quake The ground beneath Southern California moved furiously in early July 2019 due to two large earthquakes, one of which was the strongest in the region in at least two decades. Remote sensing scientists are getting better at measuring such events and showing how they disrupt and move the land surface. At 10:33 a.m. Pacific Daylight Time (PDT) on July 4, 2019, an earthquake struck northeast of Ridgecrest, California, which is north of Los Angeles and nort