Ketchikan's Seismic Design Category, explained

Ketchikan carries Seismic Design Category B under USGS's ASCE 7-16 model. Low seismic hazard. Code requires basic seismic detailing (bracing, connections) but no special structural system restrictions. Nationally, Ketchikan ranks above 59% of the 4,875 cities in this dataset for seismic hazard - the 59th percentile.

How Ketchikan compares

USGS's underlying values for Ketchikan: 0.114g peak ground acceleration, 0.301g at short period, 0.248g at 1 second. Within Alaska alone, Ketchikan ranks 11 of 11 cities by seismic hazard - the 0th percentile in-state. Ketchikan has a population of about 8,033.

Retrofit economics for Ketchikan

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 Alaska 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 Alaska.

Earthquake insurance for a Ketchikan home

A Ketchikan 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 Ketchikan's figures come from

Ketchikan'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 Ketchikan.