Marshalltown, IA: what USGS's seismic model says

Marshalltown 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. Rank it against the rest of the country and Marshalltown sits at the 16th percentile for seismic hazard among 4,875 US cities.

How Marshalltown compares

USGS's underlying values for Marshalltown: 0.029g peak ground acceleration, 0.06g at short period, 0.051g at 1 second. Within Iowa alone, Marshalltown ranks 50 of 85 cities by seismic hazard - the 42th percentile in-state. Marshalltown has a population of about 27,886.

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 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.

Earthquake insurance for a Marshalltown home

A Marshalltown 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 Marshalltown's figures come from

Marshalltown'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 Marshalltown.