Hillsborough's Seismic Design Category, explained

Under the seismic model IBC and ASCE 7 use for new construction, Hillsborough is Category B. Low seismic hazard. Code requires basic seismic detailing (bracing, connections) but no special structural system restrictions. That puts Hillsborough in the 35th percentile nationally for seismic hazard - higher than 35% of the 4,875 US cities USGS was checked against here.

Where Hillsborough sits in North Carolina

The raw figures: peak ground acceleration 0.058g, short-period spectral response 0.123g, 1-second spectral response 0.061g. Among 147 North Carolina cities in this dataset, Hillsborough ranks 112 for seismic hazard, the 24th percentile within the state. About 9,773 people live in Hillsborough, North Carolina.

Bracing and bolting: the actual cost

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

More on how this number was built

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