Troy, AL: what USGS's seismic model says

Under the seismic model IBC and ASCE 7 use for new construction, Troy is Category B. Low seismic hazard. Code requires basic seismic detailing (bracing, connections) but no special structural system restrictions. That puts Troy in the 28th percentile nationally for seismic hazard - higher than 28% of the 4,875 US cities USGS was checked against here.

How Troy compares

The raw figures: peak ground acceleration 0.047g, short-period spectral response 0.101g, 1-second spectral response 0.067g. Among 107 Alabama cities in this dataset, Troy ranks 86 for seismic hazard, the 20th percentile within the state. About 17,734 people live in Troy, Alabama.

Retrofit economics for Troy

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

More on how this number was built

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