Box Elder, SD: what USGS's seismic model says

Under the seismic model IBC and ASCE 7 use for new construction, Box Elder is Category A. Lowest seismic design category. Building code requires no seismic-specific detailing here beyond ordinary construction practice. Rank it against the rest of the country and Box Elder sits at the 16th percentile for seismic hazard among 4,875 US cities.

Box Elder by the numbers

The raw figures: peak ground acceleration 0.067g, short-period spectral response 0.132g, 1-second spectral response 0.04g. Among 18 South Dakota cities in this dataset, Box Elder ranks 4 for seismic hazard, the 82th percentile within the state. About 13,887 people live in Box Elder, South Dakota.

Bracing and bolting: the actual cost

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

Earthquake insurance for a Box Elder 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 Box Elder address.

More on how this number was built

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