Dearborn's Seismic Design Category, explained

Under the seismic model IBC and ASCE 7 use for new construction, Dearborn is Category B. Low seismic hazard. Code requires basic seismic detailing (bracing, connections) but no special structural system restrictions. Rank it against the rest of the country and Dearborn sits at the 31th percentile for seismic hazard among 4,875 US cities.

Dearborn by the numbers

The raw figures: peak ground acceleration 0.052g, short-period spectral response 0.103g, 1-second spectral response 0.046g. Among 153 Michigan cities in this dataset, Dearborn ranks 35 for seismic hazard, the 78th percentile within the state. About 106,377 people live in Dearborn, Michigan.

Retrofit economics for Dearborn

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

More on how this number was built

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