Study: 6.9 earthquake in San Diego could cause catastrophic damage

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SAN DIEGO — A magnitude 6.9 earthquake on San Diego’s Rose Canyon Fault could damage 100,000 residences, cause widespread road and bridge failures and make parts of Mission Bay sink about a foot, according to a new report from quake experts.

A study by the San Diego chapter of the Earthquake Engineering Research Institute found that such a temblor could also cut gas and water service between La Jolla and the Silver Strand for months, collapse key municipal buildings, and close the San Diego-Coronado Bridge, the San Diego Union-Tribune reported.

Parts of the fault would also rupture the Earth’s surface and shift the landscape 6 to 7 feet, damaging streets so badly that it would make it hard for police, firefighters and paramedics to get around, according to the newspaper.

The study estimates that the quake would inflict $38 billion in building and infrastructure damage, displacing 36,000 households and disrupting San Diego’s $245 billion economy.

“We’ve been working on this study for five years, and it’s been a real wake-up call for stakeholders,” Jorge Meneses, president of EERI-San Diego, told the Union-Tribune. “They were not aware of all the possible consequences. But they have time to make San Diego more resilient to the kind of damages that could occur.”

EERI is a national technological society whose scientists and engineers evaluate the risk and consequence of large quakes in places like the Bay Area and Seattle’s Puget Sound. The group collaborates with government and first-responders to mitigate potential disaster.

In 2015, EERI focused its attention on the Rose Canyon Fault, which begins beneath the seafloor off Oceanside and extends south, coming ashore in La Jolla, where it proceeds through Mount Soledad and Rose Canyon, along Interstate 5, the Union-Tribune reported.

Scientists say the fault then cuts through Old Town, Little Italy and downtown San Diego before heading offshore at the Silver Strand and stretching down the coast to roughly Tijuana, according to the newspaper.

Branches of the fault exist beneath San Diego International Airport, which handles nearly 70,000 airline passengers a day, as well as the San Diego Convention Center and Tenth Avenue Marine Terminal.

The fault — like the better-known San Andreas — is a strike-slip system. When it slips, one side of the fault moves horizontally in relation to the other.

Meneses and other scientists don’t believe that a quake is imminent on the Rose Canyon Fault, which appears to produce a major temblor roughly once every 700 years, the newspaper reported.

The last significant quake, measuring 6.0, occurred in 1862. The new report says there’s only an 18 percent chance that a fault that is within the county, or just offshore, would produce a 6.7 or larger quake in the next 30 years.

Experts say being prepared is the key. Have at least three days’ food and water and have a rally point set for your family, because cellphones most likely won’t work.

Keep medical supplies in an easily accessible place, possibly in a shed or a low structure. Recently constructed buildings are expected to fair well, but buildings over 80 years old could be a problem.

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