The city is seeking possible new requirements for the city's un-reinforced masonry buildings estimated to number up to 1,000, most of which have not been seismically retrofitted.

A study summarizes the experience of several California cities that instituted a similar requirement over the past two decades. Those cities offered 10 years or more for building owners to meet the new requirements.

In the Nisqually earthquake of 2001, a relatively mild seismic event, two-thirds of the buildings in Seattle that were closed due to earthquake damage were un-reinforced masonry structures. Currently, Seattle requires seismic retrofits when a building is undergoing substantial alterations or substantially increasing the number of occupants in the building.

In the coming months a technical committee will convene to begin assessing what seismic standard would be required if the new mandatory fix is adopted. If enacted, Seattle would be the first city outside California to have such a requirement. Scientific information in recent years has raised the projected risk of significant damage from earthquakes in Seattle.