Pennsylvania has low seismicity with occasional small earthquakes, more common in the west and southeast.
The only real protection is a warning the moment the ground moves - which is exactly what the free QuakeMate app gives you, along with tsunami and volcano alerts for Pennsylvania.
What the record shows for Pennsylvania
Over the last 20 years, USGS has catalogued 3 earthquakes of magnitude 4 or greater within 300 km of Pennsylvania - about one every 5 years. That rate describes how often the ground moves enough to be recorded, not how often damage occurs; most of these are never felt.
The NOAA NCEI database records 5 tsunamis within 300 km of Pennsylvania between 1755 and 1929. The most significant was in 1840 near Philadelphia, Pennsylvania, triggered by an M5.2 earthquake.
Sources: USGS earthquake catalog, NOAA tsunami database, and the Smithsonian Global Volcanism Program. Figures update as the catalogs are revised.
Check Pennsylvania hazard risk in detail
An interactive breakdown of the earthquake, tsunami and volcano risk in Pennsylvania - or search any city or region.
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Earthquake risk in Pennsylvania - FAQ
Is Pennsylvania at risk of earthquakes?
Yes. On average about 1 quake every 5 years nearby of magnitude 4+ within 300 km, based on the last 20 years of USGS data.
What was the biggest earthquake in Pennsylvania?
We don't have a standout large earthquake on record close to Pennsylvania in the modern catalog, though smaller quakes can still occur.
Does Pennsylvania get tsunamis?
Yes - 5 tsunamis since 1755 (most recently 1929) within 300 km, from the NOAA database.
How do I get earthquake warnings in Pennsylvania?
Download the free QuakeMate app for iPhone. It watches your location and sends a real-time push the instant a quake strikes nearby, plus tsunami and volcano alerts, with custom magnitude and distance rules. On Android, join the waitlist.