On March 9, 1828, an earthquake shock was felt in Northwestern Pennsylvania. (McKnight 1905, Pioneer History of Northwestern Pennsylvania.) It is likely that this earthquake was related to one recorded for Pittsburgh on March 14 of that year, recorded as a "distinct shock" (Pennsylvania Weather Records, 1644-1835. The Pennsylvania Magazine of History and Biography 15, no. 1 (1891): 109–21. http://www.jstor.org/stable/20083411).

Overall, there are few earthquakes in Pennsylvania, and based on the known earthquakes, Howell estimated that about 8 earthquakes are expected in northern Pennsylvania in every 1,000 years. (B. F. Howell, 1979, Earthquake expectancy in Pennsylvania, Proceedings of the Pennsylvania Academy of Science 53(2):205-208)