Does Altus, OK need an earthquake retrofit?

Altus carries Seismic Design Category B under USGS's ASCE 7-16 model. Low seismic hazard. Code requires basic seismic detailing (bracing, connections) but no special structural system restrictions. Rank it against the rest of the country and Altus sits at the 55th percentile for seismic hazard among 4,875 US cities.

Altus by the numbers

The raw figures: peak ground acceleration 0.096g, short-period spectral response 0.182g, 1-second spectral response 0.063g. Among 75 Oklahoma cities in this dataset, Altus ranks 40 for seismic hazard, the 47th percentile within the state. About 18,543 people live in Altus, Oklahoma.

Bracing and bolting: the actual cost

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 Altus address.

More on how this number was built

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