Does Culpeper, VA need an earthquake retrofit?

Under the seismic model IBC and ASCE 7 use for new construction, Culpeper 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 Culpeper sits at the 55th percentile for seismic hazard among 4,875 US cities.

How Culpeper compares

The raw figures: peak ground acceleration 0.097g, short-period spectral response 0.175g, 1-second spectral response 0.05g. Among 63 Virginia cities in this dataset, Culpeper ranks 22 for seismic hazard, the 66th percentile within the state. About 21,464 people live in Culpeper, Virginia.

Bracing and bolting: the actual cost

Outside California, no state-level retrofit grant equivalent to Brace + Bolt could be found for Virginia. 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 Culpeper address.

More on how this number was built

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