Does Lewisville, NC need an earthquake retrofit?

USGS's ASCE 7-16 seismic design model - the same standard building codes use - places Lewisville in Seismic Design Category B: Low seismic hazard. Code requires basic seismic detailing (bracing, connections) but no special structural system restrictions. Nationally, Lewisville ranks above 52% of the 4,875 cities in this dataset for seismic hazard - the 52th percentile.

Where Lewisville sits in North Carolina

The raw figures: peak ground acceleration 0.086g, short-period spectral response 0.169g, 1-second spectral response 0.07g. Among 147 North Carolina cities in this dataset, Lewisville ranks 64 for seismic hazard, the 57th percentile within the state. About 14,203 people live in Lewisville, North Carolina.

Retrofit economics for Lewisville

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.

What this means for insurance

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 Lewisville address.

More on how this number was built

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