Does Glenwood, IL need an earthquake retrofit?

Under the seismic model IBC and ASCE 7 use for new construction, Glenwood 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 Glenwood sits at the 38th percentile for seismic hazard among 4,875 US cities.

Where Glenwood sits in Illinois

USGS's underlying values for Glenwood: 0.061g peak ground acceleration, 0.123g at short period, 0.067g at 1 second. Within Illinois alone, Glenwood ranks 232 of 330 cities by seismic hazard - the 30th percentile in-state. Glenwood has a population of about 8,413.

Retrofit economics for Glenwood

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.

Insuring against this, not just retrofitting

A Glenwood 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 Glenwood's figures come from

Glenwood'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 Glenwood.