LOS ANGELES (CBSLA.com) — As Southern California residents take in images of Napa buildings left crumbling from Sunday’s quake, many are wondering what’s being done to reinforce historic buildings locally.

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The City of Los Angeles is in the process of retrofitting many of its older buildings but CBS2/KCAL9 reporter Adrianna Weingold shows how that may not stand up against a “big one.”

Longtime Altadena resident Denise Alexander is worried buildings in L.A. may not be able to withstand a strong temblor.

“I have a lot of concerns. I think, sometimes, action takes longer. I hope that whoever is involved is taking action because that could be us,” Alexander said, referring to Napa’s quake aftermath.

The Northern California quake registered at magnitude 6.0 and was strong enough to send bricks falling to the ground.

Tom Heaton, director of earthquake engineering at Caltech, said even buildings that have been retrofitted can still crumble.

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“Trying to go into an old building and make it like a new building, it’s not really possible,” Heaton said.

He said the buildings in Napa were vulnerable because they were made of brick, which can never be made safe in the event of an earthquake. Heaton said the wood structures seen across L.A. are built to withstand earthquakes.

“After you retrofit, the building is much stronger that it was without the retrofit, and it’s much less likely it will kill someone. That said, I think you’d still rather be in a new building than an old retrofitted one,” Heaton said.

For residents like David Vega, the Napa quake was a scary reminder of what can happen when a sizable earthquake hits.

“Earthquakes are very unpredictable: what they do, how they’re going to destroy and how they roll,” the Highland Park resident said. “If it comes, it comes. You’re just going to have to get out of the way of things.”

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Heaton said the city is working to identify the most vulnerable buildings in L.A. and develop a plan to fix them before the Southland is met with its own massive quake.