Ridgecrest was the epicenter of two major earthquakes in Southern California for two consecutive days during the Fourth of July weekend.
An earthquake registering a magnitude of 7.1 — California’s strongest quake in two decades — hit just outside of the Mojave Desert town Friday evening at 8:19 p.m., 34 hours after a 6.4 magnitude earthquake struck the same fault zone.
Ridgecrest, an incorporated city of close to 29,000, is located about 150 miles northeast of Los Angeles in Kern County and is about 110 miles east of the county seat, Bakersfield.
Also significantly affected was the Naval Air Weapons Station China Lake, the city’s main employer and a sprawling weapons facility larger than Rhode Island. “NAWS China Lake is not mission capable until further notice,” according to a Facebook post by naval base officials.
It was also the site of a cluster of earthquakes in 1995, when a 5.4 magnitude quake hit 11 miles north of the town on Aug. 17 and caused over 2,500 aftershocks — smaller quakes that follow a large one — over the following five weeks, according to the Southern California Earthquake Data Center.
A second earthquake of 5.8 magnitude struck the area Sept. 20, the seismologist said, causing over 1,900 more aftershocks in the two weeks that followed.
The town lies on the Eastern California Shear Zone, a region of increased seismic activity that stretches from the San Andreas fault line near Palm Springs north-northeast across the Mojave Desert and northward into Owens Valley, according to scientists.
Earthquakes in this “Walker Lane” region are mainly caused by the movement of the North American and Pacific tectonic plates, and take nearly 25 percent of the boundary motion between the land giants. The rest of that tension, scientists say, is taken up by the San Andreas Fault, the better known north-sound fault that runs the length of Calilfornia.
Mark Ghilarducci, director of the state Office of Emergency Services, said Friday night there were numerous reports in Ridgecrest of fires, mostly the result of gas leaks. Live TV reports show the town of 29,000 took a second straight day of damage with merchandise in area grocery stories knocked off shelves and residents preparing to sleep outside as shaking continued beneath them.
Ghilarducci said the hardest hit area was the town of Trona, 20 miles northeast of Ridgecrest in San Bernardino County. Damaged roads made it difficult for officials to reach the town of 1,500 people. Of most concern was the Searles Valley Minerals plant, the town’s main employer and a manufacturer of borax materials and other compounds used in cleaners, soaps and the chemical industries.