Hawthorn Woods's Seismic Design Category, explained

Hawthorn Woods 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 Hawthorn Woods in the 33th percentile nationally for seismic hazard - higher than 33% of the 4,875 US cities USGS was checked against here.

Where Hawthorn Woods sits in Illinois

The raw figures: peak ground acceleration 0.055g, short-period spectral response 0.11g, 1-second spectral response 0.059g. Among 330 Illinois cities in this dataset, Hawthorn Woods ranks 280 for seismic hazard, the 15th percentile within the state. About 9,584 people live in Hawthorn Woods, 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 Hawthorn Woods address.

More on how this number was built

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