Belle Fourche, SD: what USGS's seismic model says

Belle Fourche carries Seismic Design Category A under USGS's ASCE 7-16 model. Lowest seismic design category. Building code requires no seismic-specific detailing here beyond ordinary construction practice. That puts Belle Fourche in the 15th percentile nationally for seismic hazard - higher than 15% of the 4,875 US cities USGS was checked against here.

Belle Fourche by the numbers

USGS's underlying values for Belle Fourche: 0.058g peak ground acceleration, 0.118g at short period, 0.039g at 1 second. Within South Dakota alone, Belle Fourche ranks 8 of 18 cities by seismic hazard - the 59th percentile in-state. Belle Fourche has a population of about 5,855.

What a retrofit costs in Belle Fourche

A full earthquake retrofit typically runs $5,000-$10,000 nationally (around $7,000 typical), driven mainly by house size and foundation type, not by South Dakota specifically. California's Earthquake Brace + Bolt grant, which covers a large share of this cost, is a California-only program and does not apply in South Dakota.

Insuring against this, not just retrofitting

A Belle Fourche homeowner cannot buy a standalone earthquake policy in most cases - it is added to an existing homeowners policy as an endorsement, so the place to start is a regular home-insurance quote.

Where Belle Fourche's figures come from

Belle Fourche's Category A and every number above trace to USGS's own ASCE 7-16 Design Maps service - see the methodology guide. See the category explainer for what Category A does and doesn't tell you about Belle Fourche.