Does Machesney Park, IL need an earthquake retrofit?

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

Where Machesney Park sits in Illinois

The raw figures: peak ground acceleration 0.052g, short-period spectral response 0.104g, 1-second spectral response 0.057g. Among 330 Illinois cities in this dataset, Machesney Park ranks 299 for seismic hazard, the 9th percentile within the state. About 22,839 people live in Machesney Park, Illinois.

What a retrofit costs in Machesney Park

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.

Insuring against this, not just retrofitting

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 Machesney Park address.

More on how this number was built

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