Concord's Seismic Design Category, explained

Under the seismic model IBC and ASCE 7 use for new construction, Concord 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 Concord in the 79th percentile nationally for seismic hazard - higher than 79% of the 4,875 US cities USGS was checked against here.

Where Concord sits in New Hampshire

USGS's underlying values for Concord: 0.267g peak ground acceleration, 0.41g at short period, 0.085g at 1 second. Within New Hampshire alone, Concord ranks 2 of 13 cities by seismic hazard - the 92th percentile in-state. Concord has a population of about 44,674.

What a retrofit costs in Concord

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 New Hampshire 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 New Hampshire.

Insuring against this, not just retrofitting

A Concord 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 Concord's figures come from

Concord'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 Concord.