Groton, CT: what USGS's seismic model says

Under the seismic model IBC and ASCE 7 use for new construction, Groton is Category B. Low seismic hazard. Code requires basic seismic detailing (bracing, connections) but no special structural system restrictions. That puts Groton in the 57th percentile nationally for seismic hazard - higher than 57% of the 4,875 US cities USGS was checked against here.

Groton by the numbers

USGS's underlying values for Groton: 0.103g peak ground acceleration, 0.188g at short period, 0.052g at 1 second. Within Connecticut alone, Groton ranks 18 of 21 cities by seismic hazard - the 15th percentile in-state. Groton has a population of about 10,160.

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 Connecticut 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 Connecticut.

Insuring against this, not just retrofitting

A Groton 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 Groton's figures come from

Groton'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 Groton.