Portland's Seismic Design Category, explained

Under the seismic model IBC and ASCE 7 use for new construction, Portland is Category A. Lowest seismic design category. Building code requires no seismic-specific detailing here beyond ordinary construction practice. Rank it against the rest of the country and Portland sits at the 10th percentile for seismic hazard among 4,875 US cities.

How Portland compares

USGS's underlying values for Portland: 0.029g peak ground acceleration, 0.06g at short period, 0.018g at 1 second. Within Texas alone, Portland ranks 274 of 384 cities by seismic hazard - the 29th percentile in-state. Portland has a population of about 20,725.

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 Texas 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 Texas.

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 A 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 A does and doesn't tell you about Portland.