Downingtown, PA: what USGS's seismic model says

Under the seismic model IBC and ASCE 7 use for new construction, Downingtown 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 Downingtown sits at the 58th percentile for seismic hazard among 4,875 US cities.

How Downingtown compares

The raw figures: peak ground acceleration 0.107g, short-period spectral response 0.19g, 1-second spectral response 0.048g. Among 193 Pennsylvania cities in this dataset, Downingtown ranks 6 for seismic hazard, the 97th percentile within the state. About 8,463 people live in Downingtown, Pennsylvania.

What a retrofit costs in Downingtown

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 Downingtown address.

More on how this number was built

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