Lexington, SC: what USGS's seismic model says
Lexington carries Seismic Design Category C under USGS's ASCE 7-16 model. Moderate seismic hazard. Code adds irregular-building restrictions and requires bracing of some nonstructural components (e.g. tall shelving, water heaters) in addition to structural detailing. Rank it against the rest of the country and Lexington sits at the 77th percentile for seismic hazard among 4,875 US cities.
How Lexington compares
USGS's underlying values for Lexington: 0.194g peak ground acceleration, 0.343g at short period, 0.111g at 1 second. Within South Carolina alone, Lexington ranks 29 of 66 cities by seismic hazard - the 57th percentile in-state. Lexington has a population of about 25,354.
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 South Carolina 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 South Carolina.
What this means for insurance
A Lexington 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 Lexington's figures come from
Lexington's Category C 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 C does and doesn't tell you about Lexington.