Troy, MI: what USGS's seismic model says

Under the seismic model IBC and ASCE 7 use for new construction, Troy 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 Troy sits at the 26th percentile for seismic hazard among 4,875 US cities.

Troy by the numbers

USGS's underlying values for Troy: 0.045g peak ground acceleration, 0.092g at short period, 0.044g at 1 second. Within Michigan alone, Troy ranks 87 of 153 cities by seismic hazard - the 43th percentile in-state. Troy has a population of about 89,209.

Retrofit economics for Troy

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 Michigan 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 Michigan.

Insuring against this, not just retrofitting

A Troy 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 Troy's figures come from

Troy'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 Troy.