Pennsylvania’s biggest earthquake, 5.2 magnitude, occurred on September 25, 1998
Jamestown, Pa., near Pennsylvania’s Pymatuning Lake, experienced a moderate earthquake on September 25, 1998. Teams of scientists from the U. S. Geological Survey, Lamont-Doherty Earth Observatory [Columbia University] and Center for Earthquake Research and Information [CERI at Memphis University], and science faculty and students from nearby Thiel College in Greenville, Pennsylvania quickly mobilized to collect information. Their information was used to describe, assess, and explain this unusual earth event. The earthquake caused significant effects to the local groundwater system.
Jamestown and nearby areas of the Commonwealth and Ohio are rarely affected by earth shaking. With the exception of several low-magnitude earthquakes that have occurred in recent years in the Lancaster–Reading area, earthquakes in Pennsylvania are unusual occurrences.
Additional information about the Pymatuning earthquake can be read and viewed at the linked sites below. In addition, general information about the earthquake hazard in Pennsylvania is provided in our Bureau’s publication, Earthquake Hazard in Pennsylvania.
More information on the Pymatuning Earthquake from the USGS
USGS Water-Resources Investigations Report 99-4170, Hydrologic Effects of the Pymatuning Earthquake of September 25, 1998, in Northwestern Pennsylvania