Does Goodlettsville, TN need an earthquake retrofit?

Under the seismic model IBC and ASCE 7 use for new construction, Goodlettsville is Category D. High seismic hazard - this is the category most of coastal California, the Pacific Northwest, and other active fault regions fall into. Code mandates significant seismic detailing and restricts irregular structural configurations. This is the category the Brace + Bolt scope (cripple-wall bracing, foundation bolting) is built for. That puts Goodlettsville in the 80th percentile nationally for seismic hazard - higher than 80% of the 4,875 US cities USGS was checked against here.

How Goodlettsville compares

The raw figures: peak ground acceleration 0.135g, short-period spectral response 0.275g, 1-second spectral response 0.139g. Among 104 Tennessee cities in this dataset, Goodlettsville ranks 52 for seismic hazard, the 50th percentile within the state. About 17,433 people live in Goodlettsville, Tennessee.

Retrofit economics for Goodlettsville

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

More on how this number was built

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