Does Palos Hills, IL need an earthquake retrofit?

USGS's ASCE 7-16 seismic design model - the same standard building codes use - places Palos Hills in Seismic Design 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 Palos Hills sits at the 41th percentile for seismic hazard among 4,875 US cities.

How Palos Hills compares

The raw figures: peak ground acceleration 0.064g, short-period spectral response 0.127g, 1-second spectral response 0.066g. Among 330 Illinois cities in this dataset, Palos Hills ranks 155 for seismic hazard, the 53th percentile within the state. About 18,026 people live in Palos Hills, Illinois.

Retrofit economics for Palos Hills

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 Palos Hills address.

More on how this number was built

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