Norwalk, IA: what USGS's seismic model says

Norwalk carries Seismic Design Category B under USGS's ASCE 7-16 model. Low seismic hazard. Code requires basic seismic detailing (bracing, connections) but no special structural system restrictions. That puts Norwalk in the 17th percentile nationally for seismic hazard - higher than 17% of the 4,875 US cities USGS was checked against here.

Where Norwalk sits in Iowa

USGS's underlying values for Norwalk: 0.03g peak ground acceleration, 0.063g at short period, 0.053g at 1 second. Within Iowa alone, Norwalk ranks 43 of 85 cities by seismic hazard - the 50th percentile in-state. Norwalk has a population of about 15,396.

Retrofit economics for Norwalk

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 Iowa 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 Iowa.

What this means for insurance

A Norwalk 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 Norwalk's figures come from

Norwalk'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 Norwalk.