New York City earthquake of 10 August 1884

Background. Seismicity in the New York City area is relatively low, and large damaging intraplate earthquakes are rare. However, when they occur in the Northeastern United States, the affected areas are much larger than for earthquakes of similar magnitude on the West Coast. The 1884 event is the largest known earthquake in the greater New York City area, occurring probably between Brooklyn and Sandy Hook.

Damage. Observations of fallen bricks and cracked plaster were reported from eastern Pennsylvania to central Connecticut. The maximum intensity was reported at two sites in western Long Island, specifically Jamaica, New York, and Amityville, New York. Chimneys were toppled in New York, New Jersey, Connecticut, and Pennsylvania, with severe property damage in Jamaica and Amityville.

Geological Context. The 1884 earthquake was probably not associated with the Ramapo fault because the strongest shaking occurred on Long Island, far from the fault's trace. Intraplate earthquakes occur when present-day stress is released along zones of weakness in the intraplate crust. The infrequency of such events poses problems for researchers unable to firmly associate earthquakes with specific geologic structures without instrumental records.