Mexico City has never cataloged its buildings to know how many are at serious risk of collapse in an earthquake

By Rong-Gong Lin II and Cecilia Sanchez

Certain types of buildings are especially vulnerable to collapse during earthquakes — and earthquake-prone Mexico City is filled with them.

Those with so-called brittle concrete frames are well-known hazards. Buildings with a weak first story, often supported by narrow columns to accommodate parking, are also known to be dangerous.

How many such buildings exist in this 573-square mile metropolis, home to nearly 9 million people, is hard to know. The government has never cataloged its real estate to identify risky structures.

Now, in the wake of the magnitude 7.1 earthquake that killed more than 360 people in September, some experts are urging city officials to do just that — so tenants can be warned and building owners can be ordered to retrofit them with steel braces or new walls.

“We have to move very fast,” while the issue is fresh in people’s minds, said Sergio Alcocer, an earthquake expert at the Institute of Engineering at the National Autonomous University of Mexico.

Such an undertaking is costly and has long been viewed as politically difficult. Many cities have resisted similar calls.

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