PENNSYLVANIA, Pa. (WHTM) — When people think of earthquakes, they usually think of the west coast getting impacted by a major quake, or even the 1974 hit movie Earthquake.

But, did you know they occur on the east coast? More specifically, Pennsylvania?

The Pennsylvania Department of Conservation and Natura Resources says that earthquakes happen due to a sudden release of stored energy along part of a fault plane within the earth.

One of these faults is called the Ramapo Fault Line. According to Columbia University, this fault is part of a system of north-east striking, southeast-dipping faults, which are mapped from southeastern New York to eastern Pennsylvania and beyond.

This fault was active at different times during the evolution of the Appalachians. Another area that is closer to the Midstate is the Lancaster Seismic Zone (LSZ).

The DCNR says that the state’s most active seismic region is Southeastern Pennsylvania, saying that earthquakes of less than 4.7 on the Richter Scale have been felt in this area of the Commonwealth for at least 200 years.

Lancaster County is the county with the most seismic activity, with 26 recorded earthquakes between 1752 to 2000 according to the DCNR, with Philadephia county coming in second with 20 quakes.

One of the more well-known eastern United States earthquakes was the 5.8 magnitude earthquake of Aug. 23, 2011, which occurred in Mineral, Virginia. This occurred in the Central Virginia Seismic Zone. According to the United State Geological Survey, the quake was felt by one-third of the country’s population and there was reported damage as far away as South Carolina. More information, as well as a full report on this 2011 earthquake, can be found here.

In the past five years, 14 earthquakes have impacted the Midstate. The strongest one is near Delaware at 4.1 magnitudes. The closest quake to Harrisburg in the past five years occurred in Dover, York County, coming in at a 1.7 magnitude quake.