Littleton's Seismic Design Category, explained

USGS's ASCE 7-16 seismic design model - the same standard building codes use - places Littleton 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 Littleton sits at the 60th percentile for seismic hazard among 4,875 US cities.

How Littleton compares

The raw figures: peak ground acceleration 0.126g, short-period spectral response 0.224g, 1-second spectral response 0.06g. Among 79 Colorado cities in this dataset, Littleton ranks 25 for seismic hazard, the 69th percentile within the state. About 44,879 people live in Littleton, Colorado.

Retrofit economics for Littleton

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

Earthquake insurance for a Littleton 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 Littleton address.

More on how this number was built

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