Matthews's Seismic Design Category, explained

Under the seismic model IBC and ASCE 7 use for new construction, Matthews is Category C. 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. That puts Matthews in the 70th percentile nationally for seismic hazard - higher than 70% of the 4,875 US cities USGS was checked against here.

Matthews by the numbers

USGS's underlying values for Matthews: 0.105g peak ground acceleration, 0.206g at short period, 0.084g at 1 second. Within North Carolina alone, Matthews ranks 28 of 147 cities by seismic hazard - the 82th percentile in-state. Matthews has a population of about 32,048.

What a retrofit costs in Matthews

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 North 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 North Carolina.

Insuring against this, not just retrofitting

A Matthews 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 Matthews's figures come from

Matthews'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 Matthews.