West Chester, PA: what USGS's seismic model says

West Chester carries Seismic Design Category B under USGS's ASCE 7-16 model. 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 West Chester sits at the 57th percentile for seismic hazard among 4,875 US cities.

West Chester by the numbers

The raw figures: peak ground acceleration 0.105g, short-period spectral response 0.187g, 1-second spectral response 0.048g. Among 193 Pennsylvania cities in this dataset, West Chester ranks 11 for seismic hazard, the 95th percentile within the state. About 22,758 people live in West Chester, Pennsylvania.

Retrofit economics for West Chester

Outside California, no state-level retrofit grant equivalent to Brace + Bolt could be found for Pennsylvania. 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 West Chester address.

More on how this number was built

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