A big earthquake would topple countless buildings, but many California cities ignore the danger

LOS ANGELES - The Northridge earthquake that hit 25 years ago offered alarming evidence of how vulnerable many types of buildings are to collapse from major shaking.

It toppled hundreds of apartments, smashed brittle concrete structures and tore apart brick buildings.

Since then, some California cities have taken significant steps to make those buildings safer by requiring costly retrofitting aimed at protecting those inside and preserving the housing supply.

But many others have ignored the seismic threat. And that has created an uneven landscape that in the coming years will leave some cities significantly better prepared to withstand a big quake than others.

Other than hospitals, state government has generally not set any mandatory rules for earthquake retrofits, and that has left it up to city and county governments to make decisions about seismic risks.

And because the public generally doesn't keep tabs on municipal retrofit laws, many could be in the dark about which cities might be more dangerous than others in an earthquake.