Boston's Seismic Design Category, explained

USGS's ASCE 7-16 seismic design model - the same standard building codes use - places Boston in Seismic Design Category B: Low seismic hazard. Code requires basic seismic detailing (bracing, connections) but no special structural system restrictions. Rank it against the rest of the country and Boston sits at the 62th percentile for seismic hazard among 4,875 US cities.

How Boston compares

The raw figures: peak ground acceleration 0.156g, short-period spectral response 0.264g, 1-second spectral response 0.065g. Among 58 Massachusetts cities in this dataset, Boston ranks 26 for seismic hazard, the 56th percentile within the state. About 673,458 people live in Boston, Massachusetts.

Retrofit economics for Boston

Outside California, no state-level retrofit grant equivalent to Brace + Bolt could be found for Massachusetts. A typical retrofit still runs $5,000-$10,000 nationally, about $7,000 for a common single-family job.

What this means for insurance

Outside California, earthquake coverage is typically sold as an endorsement added to a standard homeowners policy, not a separate product - worth asking about directly when getting a home-insurance quote for a Boston address.

More on how this number was built

The methodology guide covers exactly how USGS's public design-maps API produced Boston's numbers. The guide to what a Seismic Design Category actually means covers why a category is never a substitute for an engineer's assessment of one specific house.