Ottumwa's Seismic Design Category, explained

Ottumwa 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. That puts Ottumwa in the 19th percentile nationally for seismic hazard - higher than 19% of the 4,875 US cities USGS was checked against here.

Ottumwa by the numbers

The raw figures: peak ground acceleration 0.037g, short-period spectral response 0.078g, 1-second spectral response 0.064g. Among 85 Iowa cities in this dataset, Ottumwa ranks 14 for seismic hazard, the 85th percentile within the state. About 25,648 people live in Ottumwa, Iowa.

Retrofit economics for Ottumwa

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

Earthquake insurance for a Ottumwa home

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 Ottumwa address.

More on how this number was built

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