Carlisle, PA: what USGS's seismic model says

USGS's ASCE 7-16 seismic design model - the same standard building codes use - places Carlisle in Seismic Design Category A: Lowest seismic design category. Building code requires no seismic-specific detailing here beyond ordinary construction practice. That puts Carlisle in the 16th percentile nationally for seismic hazard - higher than 16% of the 4,875 US cities USGS was checked against here.

Carlisle by the numbers

USGS's underlying values for Carlisle: 0.063g peak ground acceleration, 0.124g at short period, 0.042g at 1 second. Within Pennsylvania alone, Carlisle ranks 163 of 193 cities by seismic hazard - the 16th percentile in-state. Carlisle has a population of about 22,517.

Retrofit economics for Carlisle

A full earthquake retrofit typically runs $5,000-$10,000 nationally (around $7,000 typical), driven mainly by house size and foundation type, not by Pennsylvania specifically. California's Earthquake Brace + Bolt grant, which covers a large share of this cost, is a California-only program and does not apply in Pennsylvania.

Insuring against this, not just retrofitting

A Carlisle homeowner cannot buy a standalone earthquake policy in most cases - it is added to an existing homeowners policy as an endorsement, so the place to start is a regular home-insurance quote.

Where Carlisle's figures come from

Carlisle's Category A and every number above trace to USGS's own ASCE 7-16 Design Maps service - see the methodology guide. See the category explainer for what Category A does and doesn't tell you about Carlisle.