Does Wilmington, IL need an earthquake retrofit?

Under the seismic model IBC and ASCE 7 use for new construction, Wilmington is Category B. Low seismic hazard. Code requires basic seismic detailing (bracing, connections) but no special structural system restrictions. That puts Wilmington in the 44th percentile nationally for seismic hazard - higher than 44% of the 4,875 US cities USGS was checked against here.

How Wilmington compares

The raw figures: peak ground acceleration 0.069g, short-period spectral response 0.138g, 1-second spectral response 0.071g. Among 330 Illinois cities in this dataset, Wilmington ranks 105 for seismic hazard, the 68th percentile within the state. About 5,629 people live in Wilmington, Illinois.

What a retrofit costs in Wilmington

Outside California, no state-level retrofit grant equivalent to Brace + Bolt could be found for Illinois. A typical retrofit still runs $5,000-$10,000 nationally, about $7,000 for a common single-family job.

Earthquake insurance for a Wilmington 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 Wilmington address.

More on how this number was built

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