Lancaster, PA: what USGS's seismic model says

Under the seismic model IBC and ASCE 7 use for new construction, Lancaster is Category B. Low seismic hazard. Code requires basic seismic detailing (bracing, connections) but no special structural system restrictions. That puts Lancaster in the 57th percentile nationally for seismic hazard - higher than 57% of the 4,875 US cities USGS was checked against here.

Where Lancaster sits in Pennsylvania

USGS's underlying values for Lancaster: 0.106g peak ground acceleration, 0.189g at short period, 0.048g at 1 second. Within Pennsylvania alone, Lancaster ranks 8 of 193 cities by seismic hazard - the 96th percentile in-state. Lancaster has a population of about 58,441.

What a retrofit costs in Lancaster

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 Lancaster 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 Lancaster's figures come from

Lancaster's Category B 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 B does and doesn't tell you about Lancaster.