Does Lynn, MA need an earthquake retrofit?

Under the seismic model IBC and ASCE 7 use for new construction, Lynn is 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 Lynn sits at the 66th percentile for seismic hazard among 4,875 US cities.

How Lynn compares

The raw figures: peak ground acceleration 0.182g, short-period spectral response 0.299g, 1-second spectral response 0.069g. Among 58 Massachusetts cities in this dataset, Lynn ranks 13 for seismic hazard, the 79th percentile within the state. About 103,489 people live in Lynn, Massachusetts.

What a retrofit costs in Lynn

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.

Earthquake insurance for a Lynn home

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 Lynn address.

More on how this number was built

The methodology guide covers exactly how USGS's public design-maps API produced Lynn'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.