Does Alcoa, TN need an earthquake retrofit?

Under the seismic model IBC and ASCE 7 use for new construction, Alcoa is Category D. 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. Nationally, Alcoa ranks above 90% of the 4,875 cities in this dataset for seismic hazard - the 90th percentile.

Alcoa by the numbers

USGS's underlying values for Alcoa: 0.5g peak ground acceleration, 0.867g at short period, 0.158g at 1 second. Within Tennessee alone, Alcoa ranks 15 of 104 cities by seismic hazard - the 86th percentile in-state. Alcoa has a population of about 13,588.

Retrofit economics for Alcoa

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.

Insuring against this, not just retrofitting

A Alcoa 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 Alcoa's figures come from

Alcoa'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 Alcoa.