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Politics

Ridgecrest earthquakes caused major damage at China Lake naval base

RIDGECREST, CA - JULY 9, 2019 - Traffic is reflected in the front window of a home at 436 N. Alford
After last week’s back-to-back earthquakes, a damaged home in Ridgecrest, Calif., was red-tagged and deemed unsafe this week by the Ridgecrest Police Department.
(Genaro Molina / Los Angeles Times)

Last week’s back-to-back earthquakes hit the Naval Air Weapons Station China Lake with such violent force that they damaged the base’s elementary school and created the largest surface chasms caused by the recent temblors in Southern California’s high desert area, according to state officials.

Though there was not widespread destruction in areas near the quakes’ epicenters, officials with the state Seismic Safety Commission said at a teleconference in Sacramento on Thursday that additional structural damage to building interiors in the nearby city of Ridgecrest is being discovered, including collapsed roofs.

Preliminary reports indicate that the largest surface ruptures caused by the magnitude 6.4 earthquake on July 4 and magnitude 7.1 temblor on July 5 occurred at the naval base, according to commission Chairman Mike Gardner. The naval facility remains open to essential personnel only, though one of the base’s squadrons has resumed normal flight operations, according to the station’s Facebook page.

“Because of the nature of the base and the activity that occurs there, there is really very limited public information about impacts and recovery,” said Gardner, who is also a Riverside City Council member.

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Richmond Elementary School, which is on the naval base, “took the biggest hit” of all the public schools in the Ridgecrest area, said Jim Hackett of the Division of the State Architect, the agency that inspected the campuses. Along with a water main break, inspectors found signs of “heaving and cracking” in concrete walkways, leading them to recommend that a more detailed damage assessment be conducted, he said.

After the earthquakes, most of the personnel on the 1.2-million-acre naval base were evacuated to Naval Base Ventura County.

Officials at the Naval Air Weapons Station China Lake could not be reached for comment, but an announcement on the base’s Facebook page said its family housing facilities are expected to reopen as early as Monday.

The Seismic Safety Commission investigates earthquakes, including resulting damage and government response, and advises the governor and state Legislature on policies to reduce risksarthquakes. The 15-member board includes representatives from state agencies and local governments as well as members with expertise in seismology and geology.

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Commissioner Ivan Wong, a seismologist with Lettis Consultants International in Northern California, said his company has studied the earthquake risks and geology at the naval station and has been granted access to the base to assess how it was affected geologically by the earthquakes.

“The area around Ridgecrest is just literally crawling with faults,” Wong said at Thursday’s briefing.

Commissioner H. Kit Miyamoto, chief executive and president of earthquake structural engineering company Miyamoto International, said his company sent a team to inspect buildings in Ridgecrest after the earthquakes.

While most homes and buildings survived with minimal damage, the violent quakes caused structural problems that were hard to see from the street, he said. One grocery story had a roof so damaged that it appeared to be a “total loss,” Miyamoto said.

Fred Turner, the commission’s structural engineer, said building assessment teams have found three buildings in Ridgecrest with collapsed interior roofs that appeared undamaged from the outside. As a result, emergency responders have been advised to place a greater emphasis on interior inspections.

The commission’s senior engineering geologist, Bob Anderson, told members that the fault ruptures that caused the quakes are still being assessed.

An even bigger quake may be possible along the fault line at some point. Earlier this week, scientists said the probability of another earthquake of magnitude 7 or greater resulting from the July 5 quake was less than 1%.

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phil.willon@latimes.com

Twitter: @philwillon


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