Does Arnold, MO need an earthquake retrofit?

Under the seismic model IBC and ASCE 7 use for new construction, Arnold 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 Arnold sits at the 84th percentile for seismic hazard among 4,875 US cities.

Arnold by the numbers

USGS's underlying values for Arnold: 0.269g peak ground acceleration, 0.471g at short period, 0.169g at 1 second. Within Missouri alone, Arnold ranks 16 of 135 cities by seismic hazard - the 89th percentile in-state. Arnold has a population of about 21,036.

Retrofit economics for Arnold

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.

What this means for insurance

A Arnold 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 Arnold's figures come from

Arnold'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 Arnold.