Does Johnstown, CO need an earthquake retrofit?

Under the seismic model IBC and ASCE 7 use for new construction, Johnstown 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 Johnstown sits at the 53th percentile for seismic hazard among 4,875 US cities.

Johnstown by the numbers

USGS's underlying values for Johnstown: 0.089g peak ground acceleration, 0.171g at short period, 0.053g at 1 second. Within Colorado alone, Johnstown ranks 66 of 79 cities by seismic hazard - the 17th percentile in-state. Johnstown has a population of about 20,639.

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 Colorado 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 Colorado.

What this means for insurance

A Johnstown 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 Johnstown's figures come from

Johnstown'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 Johnstown.