Only five of Oregon's roughly 4,000 state-owned buildings would remain standing and usable after a major Cascadia Subduction Zone earthquake.

State resilience officer Jonna Papaefthimiou revealed the news to engineers and officials at the 13th National Conference on Earthquake Engineering in Portland on Friday, July 17.

According to projections cited in Gov. Tina Kotek's 2025 executive order on seismic safety, there is a 42% chance that a partial rupture of the Cascadia fault will produce a magnitude 7.4 or greater quake within the next 50 years.

A full rupture reaching magnitude 8.7 or higher carries a 16–22% probability in the same window.

The fault last ruptured in 1700 with an estimated magnitude 9.0 earthquake.

Bridges and water at risk

ODOT has identified $40 million in needed seismic upgrades to bridges statewide that, if left unaddressed, leave those crossings vulnerable to collapse in a major quake, according to Yumei Wang, a civil engineering and infrastructure resilience expert at Portland State University who spoke at the conference.

One bright spot for local commuters: the I-205 Abernethy Bridge connecting West Linn and Oregon City is on track to become the first earthquake-ready interstate bridge over the Willamette River when its seismic retrofit wraps up in late 2026.

The bridge carries more than 100,000 vehicles a day.

Elsewhere, critical links remain exposed. Mike Britch, engineering and construction manager at Tualatin Valley Water District, said the Roy Rogers Road bridge over the Tualatin River would not survive the Big One, stranding residents south of the crossing from hospitals.

"If I could create a policy and make people do things, I would say I want the state to identify some of these really critical corridors," Britch said at the July 17 conference. "We need some sort of policy to address that."

Port, power grid face gaps

The Port of Portland needs nearly $500 million to upgrade a runway capable of handling large FEMA aircraft for post-quake recovery, engineer Tom Wharton told the conference.

A National Institute of Building Sciences study found that investment would yield a net $7 billion savings benefit during recovery. Port officials said they plan to bring the proposal to Kotek's office for budget discussions.

Leon Kempner, a Bonneville Power Administration engineer, said BPA did not begin implementing seismic code into projects until the 1980s and lacks resources to retrofit the Northwest electricity grid as quickly as needed.

BPA controls most of the region's power distribution.

State action and local preparedness

Kotek signed Executive Order 25-22 on September 8, 2025, requiring all new state buildings over 10,000 square feet to meet the highest seismic safety standards immediately.

The order mandates all state executive branch buildings be retrofitted or replaced by 2060, with priority given to structures supporting first responders.

Closer to home, River Grove Elementary, the Lake Oswego School District's newest school, was built to Seismic Level IV standards and is designed to serve as a community emergency gathering hub after a disaster.

The Oregon Department of Emergency Management recommends residents keep two weeks' worth of food, water, and supplies on hand.

The agency advises securing heavy furniture to walls, learning how to shut off gas and water lines, and practicing Drop, Cover, and Hold On.

Residents can sign up for local emergency alerts at ORAlert.gov and access OEM's free Be 2 Weeks Ready toolkit at oregon.gov/oem.