Storm Lake's Seismic Design Category, explained

Under the seismic model IBC and ASCE 7 use for new construction, Storm Lake is Category A. Lowest seismic design category. Building code requires no seismic-specific detailing here beyond ordinary construction practice. Nationally, Storm Lake ranks above 10% of the 4,875 cities in this dataset for seismic hazard - the 10th percentile.

How Storm Lake compares

The raw figures: peak ground acceleration 0.029g, short-period spectral response 0.061g, 1-second spectral response 0.04g. Among 85 Iowa cities in this dataset, Storm Lake ranks 79 for seismic hazard, the 7th percentile within the state. About 11,627 people live in Storm Lake, Iowa.

What a retrofit costs in Storm Lake

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.

Insuring against this, not just retrofitting

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 Storm Lake address.

More on how this number was built

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