Sergeant Bluff, IA: what USGS's seismic model says

USGS's ASCE 7-16 seismic design model - the same standard building codes use - places Sergeant Bluff in Seismic Design Category A: Lowest seismic design category. Building code requires no seismic-specific detailing here beyond ordinary construction practice. Nationally, Sergeant Bluff ranks above 13% of the 4,875 cities in this dataset for seismic hazard - the 13th percentile.

Sergeant Bluff by the numbers

The raw figures: peak ground acceleration 0.039g, short-period spectral response 0.081g, 1-second spectral response 0.04g. Among 85 Iowa cities in this dataset, Sergeant Bluff ranks 73 for seismic hazard, the 14th percentile within the state. About 5,335 people live in Sergeant Bluff, Iowa.

Bracing and bolting: the actual cost

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 Sergeant Bluff address.

More on how this number was built

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