Collegedale's Seismic Design Category, explained

Under the seismic model IBC and ASCE 7 use for new construction, Collegedale is Category C. Moderate seismic hazard. Code adds irregular-building restrictions and requires bracing of some nonstructural components (e.g. tall shelving, water heaters) in addition to structural detailing. Rank it against the rest of the country and Collegedale sits at the 79th percentile for seismic hazard among 4,875 US cities.

Collegedale by the numbers

The raw figures: peak ground acceleration 0.355g, short-period spectral response 0.534g, 1-second spectral response 0.127g. Among 104 Tennessee cities in this dataset, Collegedale ranks 63 for seismic hazard, the 40th percentile within the state. About 11,510 people live in Collegedale, Tennessee.

What a retrofit costs in Collegedale

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.

Earthquake insurance for a Collegedale home

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 Collegedale address.

More on how this number was built

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