Rock Springs's Seismic Design Category, explained

Under the seismic model IBC and ASCE 7 use for new construction, Rock Springs is Category C. Moderate seismic hazard. Code adds irregular-building restrictions and requires bracing of some nonstructural components (e.g. tall shelving, water heaters) in addition to structural detailing. Nationally, Rock Springs ranks above 77% of the 4,875 cities in this dataset for seismic hazard - the 77th percentile.

Where Rock Springs sits in Wyoming

USGS's underlying values for Rock Springs: 0.196g peak ground acceleration, 0.327g at short period, 0.085g at 1 second. Within Wyoming alone, Rock Springs ranks 7 of 16 cities by seismic hazard - the 60th percentile in-state. Rock Springs has a population of about 22,967.

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 Wyoming 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 Wyoming.

Insuring against this, not just retrofitting

A Rock Springs 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 Rock Springs's figures come from

Rock Springs's Category C 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 C does and doesn't tell you about Rock Springs.