Does Garden City, MI need an earthquake retrofit?

Under the seismic model IBC and ASCE 7 use for new construction, Garden City 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 Garden City sits at the 31th percentile for seismic hazard among 4,875 US cities.

Garden City by the numbers

The raw figures: peak ground acceleration 0.051g, short-period spectral response 0.103g, 1-second spectral response 0.046g. Among 153 Michigan cities in this dataset, Garden City ranks 41 for seismic hazard, the 74th percentile within the state. About 26,410 people live in Garden City, Michigan.

Bracing and bolting: the actual cost

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.

Earthquake insurance for a Garden City 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 Garden City address.

More on how this number was built

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