Does Northville, MI need an earthquake retrofit?

Under the seismic model IBC and ASCE 7 use for new construction, Northville 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 Northville sits at the 28th percentile for seismic hazard among 4,875 US cities.

Where Northville sits in Michigan

The raw figures: peak ground acceleration 0.048g, short-period spectral response 0.097g, 1-second spectral response 0.046g. Among 153 Michigan cities in this dataset, Northville ranks 69 for seismic hazard, the 55th percentile within the state. About 6,047 people live in Northville, Michigan.

What a retrofit costs in Northville

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 Northville 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 Northville address.

More on how this number was built

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