James Island's Seismic Design Category, explained

USGS's ASCE 7-16 seismic design model - the same standard building codes use - places James Island 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. That puts James Island in the 97th percentile nationally for seismic hazard - higher than 97% of the 4,875 US cities USGS was checked against here.

How James Island compares

USGS's underlying values for James Island: 0.801g peak ground acceleration, 1.239g at short period, 0.367g at 1 second. Within South Carolina alone, James Island ranks 8 of 66 cities by seismic hazard - the 89th percentile in-state. James Island has a population of about 12,451.

What a retrofit costs in James Island

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 James Island 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 James Island's figures come from

James Island'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 James Island.