Troutdale's Seismic Design Category, explained

Under the seismic model IBC and ASCE 7 use for new construction, Troutdale is Category D. High seismic hazard - this is the category most of coastal California, the Pacific Northwest, and other active fault regions fall into. Code mandates significant seismic detailing and restricts irregular structural configurations. This is the category the Brace + Bolt scope (cripple-wall bracing, foundation bolting) is built for. Nationally, Troutdale ranks above 87% of the 4,875 cities in this dataset for seismic hazard - the 87th percentile.

Where Troutdale sits in Oregon

The raw figures: peak ground acceleration 0.382g, short-period spectral response 0.845g, 1-second spectral response 0.36g. Among 80 Oregon cities in this dataset, Troutdale ranks 41 for seismic hazard, the 49th percentile within the state. About 15,749 people live in Troutdale, Oregon.

What a retrofit costs in Troutdale

Outside California, no state-level retrofit grant equivalent to Brace + Bolt could be found for Oregon. A typical retrofit still runs $5,000-$10,000 nationally, about $7,000 for a common single-family job.

What this means for insurance

Outside California, earthquake coverage is typically sold as an endorsement added to a standard homeowners policy, not a separate product - worth asking about directly when getting a home-insurance quote for a Troutdale address.

More on how this number was built

The methodology guide covers exactly how USGS's public design-maps API produced Troutdale's numbers. The guide to what a Seismic Design Category actually means covers why a category is never a substitute for an engineer's assessment of one specific house.