Hundreds of buildings unprepared for Seattle’s next big quake, study finds

The City of Seattle is in a race against time when it comes to earthquakes and old buildings that don’t meet modern standards to withstand them.

SEATTLE - The City of Seattle is in a race against time when it comes to earthquakes and old buildings that don’t meet modern standards to withstand them.

Prone to collapse during earthquakes, unreinforced masonry buildings have raised concerns in Seattle for some time. Seattle has cataloged more than 1,100 of these buildings—records tracked by the Seattle Department of Construction & Inspections (SDCI) show that more than 600 have yet to be retrofitted.

"Unreinforced masonry buildings have a history of performing poorly in earthquakes," said Professor Jeff Berman with the University of Washington. "More people die in unreinforced masonry buildings than in any other type of building typology."

Berman, a civil engineer, told FOX 13 News that we know what type of retrofits are required to make buildings safer, but the cost is typically the main barrier.

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As the City of Seattle moves towards a mandatory ordinance, SDCI is working to identify options to help building owners cover the cost of retrofits.

The danger, however, is a known one. In Feb. 2001, the 6.8-magnitude Nisqually quake led to 45 seconds of shaking. Hundreds of people were injured, while billions of dollars in damage were caused – with bricks toppling from buildings in Pioneer Square.

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Late last month, a representative of the Alliance for Safety Affordability and Preservation spoke at a council committee meeting voicing the need for upgrades, stating these buildings are significant risk to people living and working in them if they’re not retrofitted.

The news comes roughly a week after research published in the journal Science Advances, questioned whether an earthquake along the Seattle fault shook stronger than what current models have indicated was possible.

Bryan Black, a University of Arizona dendrochronologist who published the work, used remnants of ancient trees to prove that the Seattle fault shook either at the same time, or within a few months of the Saddle Mountain fault. It essentially rewrote known history of a massive quake that struck roughly 1,100 years ago.

"They can rupture either in rapid sequence or they could rupture almost simultaneously to be felt as one large earthquake," Black told FOX 13 News.

Harold Tobin, the director of the Pacific Northwest Seismic Network, who was not involved in the study, said that the findings need to be factored into risk calculations now.

"Stronger shaking over a wider area, or repeat shaking twice in a row impacting already damaged structures and hillsides means the risk is greater in proportion and affects a wider area," said Tobin.

It’s a reminder that we are still learning more about the seismic activity in our area, both what has already happened and what could occur in the future.

As Professor Berman explained, we are living through a time when buildings built only a few decades ago would be designed differently given everything we’ve learned in recent years.

"It’s really a dynamic environment because our understanding of the hazard is changing so rapidly," he said.

Seattle’s city councilmembers will vote on Oct. 10 on a resolution to develop their voluntary seismic retrofit ordinance. According to a city spokesperson, they hope to have a mandatory ordinance in place by the second half of 2025.