Norman's Seismic Design Category, explained

Norman carries Seismic Design Category C under USGS's ASCE 7-16 model. Moderate seismic hazard. Code adds irregular-building restrictions and requires bracing of some nonstructural components (e.g. tall shelving, water heaters) in addition to structural detailing. Rank it against the rest of the country and Norman sits at the 77th percentile for seismic hazard among 4,875 US cities.

How Norman compares

The raw figures: peak ground acceleration 0.193g, short-period spectral response 0.319g, 1-second spectral response 0.083g. Among 75 Oklahoma cities in this dataset, Norman ranks 16 for seismic hazard, the 80th percentile within the state. About 131,010 people live in Norman, Oklahoma.

Retrofit economics for Norman

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

More on how this number was built

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