Stanwood, WA: what USGS's seismic model says

Under the seismic model IBC and ASCE 7 use for new construction, Stanwood 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. Rank it against the rest of the country and Stanwood sits at the 89th percentile for seismic hazard among 4,875 US cities.

Stanwood by the numbers

The raw figures: peak ground acceleration 0.482g, short-period spectral response 1.134g, 1-second spectral response 0.405g. Among 125 Washington cities in this dataset, Stanwood ranks 73 for seismic hazard, the 42th percentile within the state. About 8,943 people live in Stanwood, Washington.

Retrofit economics for Stanwood

Outside California, no state-level retrofit grant equivalent to Brace + Bolt could be found for Washington. 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 Stanwood address.

More on how this number was built

The methodology guide covers exactly how USGS's public design-maps API produced Stanwood'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.