Birmingham's Seismic Design Category, explained

USGS's ASCE 7-16 seismic design model - the same standard building codes use - places Birmingham 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 Birmingham in the 76th percentile nationally for seismic hazard - higher than 76% of the 4,875 US cities USGS was checked against here.

How Birmingham compares

The raw figures: peak ground acceleration 0.175g, short-period spectral response 0.299g, 1-second spectral response 0.102g. Among 107 Alabama cities in this dataset, Birmingham ranks 17 for seismic hazard, the 85th percentile within the state. About 196,357 people live in Birmingham, Alabama.

Bracing and bolting: the actual cost

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.

Earthquake insurance for a Birmingham 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 Birmingham address.

More on how this number was built

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