Does Webster Groves, MO need an earthquake retrofit?

Under the seismic model IBC and ASCE 7 use for new construction, Webster Groves 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. That puts Webster Groves in the 83th percentile nationally for seismic hazard - higher than 83% of the 4,875 US cities USGS was checked against here.

How Webster Groves compares

The raw figures: peak ground acceleration 0.247g, short-period spectral response 0.436g, 1-second spectral response 0.158g. Among 135 Missouri cities in this dataset, Webster Groves ranks 22 for seismic hazard, the 84th percentile within the state. About 23,525 people live in Webster Groves, Missouri.

Retrofit economics for Webster Groves

Outside California, no state-level retrofit grant equivalent to Brace + Bolt could be found for Missouri. A typical retrofit still runs $5,000-$10,000 nationally, about $7,000 for a common single-family job.

Earthquake insurance for a Webster Groves home

Outside California, earthquake coverage is typically sold as an endorsement added to a standard homeowners policy, not a separate product - worth asking about directly when getting a home-insurance quote for a Webster Groves address.

More on how this number was built

The methodology guide covers exactly how USGS's public design-maps API produced Webster Groves's numbers. The guide to what a Seismic Design Category actually means covers why a category is never a substitute for an engineer's assessment of one specific house.