DeKalb's Seismic Design Category, explained

Under the seismic model IBC and ASCE 7 use for new construction, DeKalb is Category B. Low seismic hazard. Code requires basic seismic detailing (bracing, connections) but no special structural system restrictions. That puts DeKalb in the 45th percentile nationally for seismic hazard - higher than 45% of the 4,875 US cities USGS was checked against here.

Where DeKalb sits in Illinois

USGS's underlying values for DeKalb: 0.07g peak ground acceleration, 0.134g at short period, 0.065g at 1 second. Within Illinois alone, DeKalb ranks 93 of 330 cities by seismic hazard - the 72th percentile in-state. DeKalb has a population of about 40,491.

Bracing and bolting: the actual cost

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 DeKalb 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 DeKalb's figures come from

DeKalb'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 DeKalb.