Norwalk, CT: what USGS's seismic model says

Under the seismic model IBC and ASCE 7 use for new construction, Norwalk 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 Norwalk sits at the 61th percentile for seismic hazard among 4,875 US cities.

Norwalk by the numbers

The raw figures: peak ground acceleration 0.143g, short-period spectral response 0.242g, 1-second spectral response 0.057g. Among 21 Connecticut cities in this dataset, Norwalk ranks 2 for seismic hazard, the 95th percentile within the state. About 93,661 people live in Norwalk, Connecticut.

Retrofit economics for Norwalk

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

Insuring against this, not just retrofitting

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 Norwalk address.

More on how this number was built

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