Nashua's Seismic Design Category, explained

USGS's ASCE 7-16 seismic design model - the same standard building codes use - places Nashua in Seismic Design 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. Rank it against the rest of the country and Nashua sits at the 79th percentile for seismic hazard among 4,875 US cities.

How Nashua compares

USGS's underlying values for Nashua: 0.262g peak ground acceleration, 0.402g at short period, 0.081g at 1 second. Within New Hampshire alone, Nashua ranks 3 of 13 cities by seismic hazard - the 83th percentile in-state. Nashua has a population of about 91,851.

What a retrofit costs in Nashua

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.

What this means for insurance

A Nashua 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 Nashua's figures come from

Nashua'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 Nashua.