Does Lake St. Louis, MO need an earthquake retrofit?

Under the seismic model IBC and ASCE 7 use for new construction, Lake St. Louis 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. Rank it against the rest of the country and Lake St. Louis sits at the 80th percentile for seismic hazard among 4,875 US cities.

Where Lake St. Louis sits in Missouri

USGS's underlying values for Lake St. Louis: 0.158g peak ground acceleration, 0.304g at short period, 0.132g at 1 second. Within Missouri alone, Lake St. Louis ranks 65 of 135 cities by seismic hazard - the 52th percentile in-state. Lake St. Louis has a population of about 19,160.

What a retrofit costs in Lake St. Louis

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 Missouri 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 Missouri.

Insuring against this, not just retrofitting

A Lake St. Louis 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 Lake St. Louis's figures come from

Lake St. Louis'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 Lake St. Louis.