Earthquakes in Pennsylvania

Earthquakes in Pennsylvania are not common, although there are a few areas with a history of small events. A sudden release of stored energy along part of a fault plane within the earth causes an earthquake.

Other events can cause earth shaking, such as blasting or a mine roof collapse, but these events are not earthquakes.

Pennsylvania’s Seismic Network

DCNR, in partnership with the Department of Environmental Protection and Penn State, supports a real-time network of 30 seismic stations to monitor earthquakes in the state. These stations were strategically positioned to complement 71 other permanent stations in and near Pennsylvania.

Data from the entire network (completed in August 2016) are expected to improve our knowledge of natural earthquakes and induced seismicity. This information also will help geologists map the distribution of rock formations and underground structures.

If You Feel an Earthquake

If you believe you have felt an earthquake, you can report your experience on the U.S. Geological Survey website Did You Feel It?.  

History of Earthquakes Felt in Pennsylvania

In 1998, the largest earthquake ever recorded in Pennsylvania occurred in the region of Pymatuning Lake in the northwestern part of the state. The 5.2-magnitude earthquake caused minor structural damage but had significant effects on the local groundwater system.

The 5.8-magnitude central Virginia earthquake of 2011 was widely felt in Pennsylvania, though damages here were minor. It was the largest recorded quake in the central and eastern United States since 1944. Smaller earthquakes with epicenters in adjoining states have also been felt in Pennsylvania.

The Earthquake Catalog and Epicenter Map of Pennsylvania, published by the Pennsylvania Geological Survey, contains detailed information on historic seismic events from 1724 to July 31, 2003.