Decatur, AL: what USGS's seismic model says

USGS's ASCE 7-16 seismic design model - the same standard building codes use - places Decatur in Seismic Design 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 Decatur in the 73th percentile nationally for seismic hazard - higher than 73% of the 4,875 US cities USGS was checked against here.

How Decatur compares

The raw figures: peak ground acceleration 0.133g, short-period spectral response 0.261g, 1-second spectral response 0.119g. Among 107 Alabama cities in this dataset, Decatur ranks 59 for seismic hazard, the 45th percentile within the state. About 57,974 people live in Decatur, Alabama.

Retrofit economics for Decatur

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 Decatur address.

More on how this number was built

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