Does Joliet, IL need an earthquake retrofit?

Under the seismic model IBC and ASCE 7 use for new construction, Joliet 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 Joliet sits at the 46th percentile for seismic hazard among 4,875 US cities.

Joliet by the numbers

USGS's underlying values for Joliet: 0.071g peak ground acceleration, 0.139g at short period, 0.069g at 1 second. Within Illinois alone, Joliet ranks 86 of 330 cities by seismic hazard - the 74th percentile in-state. Joliet has a population of about 151,837.

Retrofit economics for Joliet

A full earthquake retrofit typically runs $5,000-$10,000 nationally (around $7,000 typical), driven mainly by house size and foundation type, not by Illinois specifically. California's Earthquake Brace + Bolt grant, which covers a large share of this cost, is a California-only program and does not apply in Illinois.

What this means for insurance

A Joliet homeowner cannot buy a standalone earthquake policy in most cases - it is added to an existing homeowners policy as an endorsement, so the place to start is a regular home-insurance quote.

Where Joliet's figures come from

Joliet's Category B and every number above trace to USGS's own ASCE 7-16 Design Maps service - see the methodology guide. See the category explainer for what Category B does and doesn't tell you about Joliet.