Does Portland, ME need an earthquake retrofit?

USGS's ASCE 7-16 seismic design model - the same standard building codes use - places Portland in Seismic Design Category B: Low seismic hazard. Code requires basic seismic detailing (bracing, connections) but no special structural system restrictions. That puts Portland in the 63th percentile nationally for seismic hazard - higher than 63% of the 4,875 US cities USGS was checked against here.

Portland by the numbers

USGS's underlying values for Portland: 0.163g peak ground acceleration, 0.277g at short period, 0.071g at 1 second. Within Maine alone, Portland ranks 18 of 20 cities by seismic hazard - the 11th percentile in-state. Portland has a population of about 69,568.

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 Maine 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 Maine.

What this means for insurance

A Portland 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 Portland's figures come from

Portland'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 Portland.