Ramapo Fault: Earthquake Risk, History & Live Activity
The Ramapo Fault is an ancient fault system running about 300 kilometres through New Jersey, southeastern New York, and Pennsylvania, marking the western edge of the Newark rift basin. It formed hundreds of millions of years ago and lies deep within the North American plate, far from any active plate boundary. Whether it is meaningfully more active today than the surrounding crust is a genuine and unresolved scientific debate.
How likely is a large earthquake?
The Ramapo Fault is often called the most notable fault in the greater New York City region, but its present-day activity is disputed. Small earthquakes are scattered across the wider area without concentrating along the mapped fault, and many seismologists argue that no single mapped structure has been shown to be more hazardous than the region as a whole. The USGS National Seismic Hazard Model (2023) treats the northeastern United States as a low-but-real hazard zone rather than assigning a specific probability to the Ramapo Fault.
Studies of the historical and geological record have found no clear evidence of an earthquake larger than about magnitude 5.3 to 5.5 in this area going back to 1737. The hazard here is best understood as infrequent moderate earthquakes affecting a very densely populated and largely un-retrofitted region, rather than a San Andreas-style major fault.
Live seismic activity near this fault
Counts include M2.5+ events — the smallest size USGS reports consistently worldwide.
No magnitude 2.5+ earthquakes recorded near this fault in the last 7 days.
History
The region's notable earthquakes are moderate events, and their attribution to the Ramapo Fault specifically is uncertain.
- 1737 New York City area (estimated M5.2) — toppled chimneys and was felt across the region.
- 1783 New Jersey (estimated M5.3) — long the strongest known New Jersey earthquake, felt from New Hampshire to Pennsylvania.
- 1884 near Rockaway Beach, New York (estimated M5.2) — knocked houses off foundations and toppled chimneys across the area.
- 2024 Tewksbury, New Jersey (M4.8) — the strongest New Jersey earthquake since 1783, felt across the northeastern United States.
Frequently asked questions
Is the Ramapo Fault active and dangerous?
It is an old fault in a region of low but real seismic activity, and its individual role is debated. Scientists have not shown that the Ramapo Fault produces more earthquakes than the surrounding crust, and no earthquake above about magnitude 5.5 has been documented in the area in nearly 300 years. The practical concern is that even a moderate earthquake can cause damage in a dense, older-built region like metropolitan New York.
Could a large earthquake hit the New York City area?
A truly large earthquake here is considered unlikely on the available evidence, but a moderate one, in the magnitude 5 range like the events of 1737, 1783, and 1884, is possible and has happened before. Because eastern crust transmits shaking efficiently and much of the building stock is old, even a magnitude 5 event can be felt widely and cause localized damage.
Nearby regions
Live counts from the USGS earthquake feeds within 200 km of the fault. Magnitudes and depths are automated readings and may be revised. Not for emergency use.