Larchmont's Seismic Design Category, explained

Under the seismic model IBC and ASCE 7 use for new construction, Larchmont is Category B. Low seismic hazard. Code requires basic seismic detailing (bracing, connections) but no special structural system restrictions. That puts Larchmont in the 64th percentile nationally for seismic hazard - higher than 64% of the 4,875 US cities USGS was checked against here.

Where Larchmont sits in New York

The raw figures: peak ground acceleration 0.177g, short-period spectral response 0.287g, 1-second spectral response 0.06g. Among 170 New York cities in this dataset, Larchmont ranks 37 for seismic hazard, the 79th percentile within the state. About 6,640 people live in Larchmont, New York.

What a retrofit costs in Larchmont

Outside California, no state-level retrofit grant equivalent to Brace + Bolt could be found for New York. 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 Larchmont address.

More on how this number was built

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