About 850 to 1,000 old brick buildings in Seattle could collapse during a severe earthquake, according to a city report released today. Mayor Greg Nickels plans to eventually require the owners to retrofit the buildings.

The study, by the city's Department of Planning and Development, will be presented to the City Council's emergency-planning committee this afternoon.

"We recognized that in an earthquake, they are the one with potential to have the most problems," said Diane Sugimura, director of the planning department. After the Nisqually earthquake in 2001, two-thirds of buildings deemed uninhabitable were old brick buildings dating to the 1930s.

Most of the unreinforced masonry buildings the city identified are commercial, residential or mixed-use. The majority are in Pioneer Square, the Chinatown-International District, Sodo and Capitol Hill. The city plans to notify property owners of all the buildings.

Nickels wants to appoint a technical and policy advisory committee to propose possible changes to city code. He expects the committee to spend a year studying the issue.

The committees will examine what thresholds to recommend for retrofitting, timeline, compliance standards, penalties and incentives, such as the ability to transfer development rights.

Any changes to the building code would require City Council approval.

City officials say Seattle would be the first city outside of California to require seismic retrofitting.