Collierville's Seismic Design Category, explained

Collierville carries Seismic Design Category D under USGS's ASCE 7-16 model. High seismic hazard - this is the category most of coastal California, the Pacific Northwest, and other active fault regions fall into. Code mandates significant seismic detailing and restricts irregular structural configurations. This is the category the Brace + Bolt scope (cripple-wall bracing, foundation bolting) is built for. That puts Collierville in the 88th percentile nationally for seismic hazard - higher than 88% of the 4,875 US cities USGS was checked against here.

How Collierville compares

USGS's underlying values for Collierville: 0.431g peak ground acceleration, 0.745g at short period, 0.263g at 1 second. Within Tennessee alone, Collierville ranks 25 of 104 cities by seismic hazard - the 77th percentile in-state. Collierville has a population of about 51,951.

Retrofit economics for Collierville

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 Tennessee 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 Tennessee.

What this means for insurance

A Collierville 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 Collierville's figures come from

Collierville's Category D 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 D does and doesn't tell you about Collierville.