Does Union City, TN need an earthquake retrofit?

Under the seismic model IBC and ASCE 7 use for new construction, Union City 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 Union City in the 98th percentile nationally for seismic hazard - higher than 98% of the 4,875 US cities USGS was checked against here.

How Union City compares

The raw figures: peak ground acceleration 0.955g, short-period spectral response 1.591g, 1-second spectral response 0.553g. Among 104 Tennessee cities in this dataset, Union City ranks 2 for seismic hazard, the 99th percentile within the state. About 10,876 people live in Union City, Tennessee.

What a retrofit costs in Union City

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 Union City address.

More on how this number was built

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