Winfield's Seismic Design Category, explained

Winfield carries Seismic Design Category B under USGS's ASCE 7-16 model. Low seismic hazard. Code requires basic seismic detailing (bracing, connections) but no special structural system restrictions. That puts Winfield in the 42th percentile nationally for seismic hazard - higher than 42% of the 4,875 US cities USGS was checked against here.

Winfield by the numbers

The raw figures: peak ground acceleration 0.067g, short-period spectral response 0.131g, 1-second spectral response 0.065g. Among 330 Illinois cities in this dataset, Winfield ranks 119 for seismic hazard, the 64th percentile within the state. About 10,199 people live in Winfield, Illinois.

Bracing and bolting: the actual cost

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.

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 Winfield address.

More on how this number was built

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