CHINO HILLS, Calif. - Chino Hills was just a few miles from the epicenter of Tuesday's magnitude-5.4 quake, yet it withstood the shaking with almost no damage at all, even though communities farther away saw fallen bricks, cracked walls and windows, warped door frames, and broken water mains and gas lines.
One big reason: Chino Hills went up mostly in the 1990s and was built to the stringent earthquake standards that California wants to see adopted throughout the state before the Big One strikes.
"I was wandering around out there after the quake and it struck me that there's no building there that's more than 10 years old. They're all built to the most recent codes, and I think that's true of the whole Chino area," said Lucy Jones, a seismologist with the U.S. Geological Survey. "The type of earthquake that used to be a major event just isn't anymore."
Since the 1930s, California has gradually boosted its building standards.
Each severe quake has prompted new rules, with the most recent major overhaul occurring after the 1994 quake in the Northridge section of Los Angeles that killed 72 people.
Tuesday's jolt proved to structural engineers that their work is paying off.
When the earthquake struck, Toledo lawyer Keith Wilkowski was in the west Los Angeles district of Brentwood, taking a video deposition from a witness.
Mr. Wilkowski, a former Lucas County commissioner and Toledo city law director who has taken steps toward running for mayor in next year's election, said the office building shook intensely for about 10 seconds.
"You felt the building rocking, and you didn't know what was going to happen next. And then it stopped," he said.
The camera taping the deposition was rolling at the time of the quake. The witness, caught on tape as the tremors began, resumed the deposition several minutes after the rumbling stopped.
Mr. Wilkowski said he was surprised by the nonchalance Los Angeles residents showed in the quake's aftermath.
"Everyone there takes it for granted that there's going to be a large one someday," he said. "I'll stick with our Midwest weather any day."
Experts said the quake could have produced more damage if it had been centered elsewhere.
Only about 20 percent of buildings statewide are constructed to the standards used in Chino Hills.
Of the remaining 80 percent, 40 percent would suffer major damage during a severe earthquake and 10 percent would collapse, said Chris Poland, chief executive at Degenkolb Engineers in San Francisco.
Tuesday's quake was considered moderate.
A state law passed in 1986 mandated that cities catalog all unreinforced mason structures - mostly old brick or stone buildings - and then take steps to retrofit them, a process that includes inserting steel reinforcing bars in exterior walls and bracing the interior walls with steel, too.
But the law left the retrofitting plans to individual jurisdictions.
As a result, about 30 percent of the state's nearly 26,000 brick-and-mortar structures could collapse in a large quake, according to a 2006 report by the California Seismic Safety Commission. Those include buildings with unbraced parapets and unsecured walls and roofs.33.9961 -117.7581