Does Indianola, IA need an earthquake retrofit?

Under the seismic model IBC and ASCE 7 use for new construction, Indianola is Category B. 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 Indianola sits at the 17th percentile for seismic hazard among 4,875 US cities.

Where Indianola sits in Iowa

The raw figures: peak ground acceleration 0.031g, short-period spectral response 0.064g, 1-second spectral response 0.054g. Among 85 Iowa cities in this dataset, Indianola ranks 35 for seismic hazard, the 60th percentile within the state. About 16,297 people live in Indianola, Iowa.

What a retrofit costs in Indianola

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.

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 Indianola address.

More on how this number was built

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