Gretna's Seismic Design Category, explained

USGS's ASCE 7-16 seismic design model - the same standard building codes use - places Gretna in Seismic Design Category B: Low seismic hazard. Code requires basic seismic detailing (bracing, connections) but no special structural system restrictions. Rank it against the rest of the country and Gretna sits at the 23th percentile for seismic hazard among 4,875 US cities.

Where Gretna sits in Louisiana

USGS's underlying values for Gretna: 0.042g peak ground acceleration, 0.086g at short period, 0.053g at 1 second. Within Louisiana alone, Gretna ranks 34 of 59 cities by seismic hazard - the 43th percentile in-state. Gretna has a population of about 17,185.

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 Louisiana 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 Louisiana.

Earthquake insurance for a Gretna home

A Gretna 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 Gretna's figures come from

Gretna'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 Gretna.