Highland, IL: what USGS's seismic model says

USGS's ASCE 7-16 seismic design model - the same standard building codes use - places Highland in Seismic Design 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 Highland sits at the 84th percentile for seismic hazard among 4,875 US cities.

How Highland compares

USGS's underlying values for Highland: 0.264g peak ground acceleration, 0.457g at short period, 0.16g at 1 second. Within Illinois alone, Highland ranks 28 of 330 cities by seismic hazard - the 92th percentile in-state. Highland has a population of about 10,028.

Retrofit economics for Highland

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 Illinois 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 Illinois.

Insuring against this, not just retrofitting

A Highland 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 Highland's figures come from

Highland'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 Highland.