Chattanooga, TN: what USGS's seismic model says

Under the seismic model IBC and ASCE 7 use for new construction, Chattanooga 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. That puts Chattanooga in the 79th percentile nationally for seismic hazard - higher than 79% of the 4,875 US cities USGS was checked against here.

Chattanooga by the numbers

The raw figures: peak ground acceleration 0.313g, short-period spectral response 0.481g, 1-second spectral response 0.123g. Among 104 Tennessee cities in this dataset, Chattanooga ranks 70 for seismic hazard, the 33th percentile within the state. About 191,496 people live in Chattanooga, Tennessee.

Bracing and bolting: the actual cost

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.

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 Chattanooga address.

More on how this number was built

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