Does Riverside, IL need an earthquake retrofit?

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

Riverside by the numbers

USGS's underlying values for Riverside: 0.062g peak ground acceleration, 0.123g at short period, 0.064g at 1 second. Within Illinois alone, Riverside ranks 213 of 330 cities by seismic hazard - the 36th percentile in-state. Riverside has a population of about 8,964.

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.

What this means for insurance

A Riverside 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 Riverside's figures come from

Riverside'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 Riverside.