Researchers Trace 4.8 New Jersey Quake to Mountainville Fault, Not Ramapo
Updated
Updated · Gizmodo · Aug 28
Researchers Trace 4.8 New Jersey Quake to Mountainville Fault, Not Ramapo
3 articles · Updated · Gizmodo · Aug 28
Summary
A study in JGR Solid Earth identified the April 5, 2024 magnitude 4.8 New Jersey earthquake as rupturing the previously unmapped Mountainville Fault in the New Jersey Highlands.
Aftershock patterns, LiDAR, field mapping, friction tests and stress analysis pointed to a fault zone about 2 miles west of the epicenter, while the larger Ramapo Fault was too distant and misaligned with the seismic signal.
Researchers said the Mountainville structure appears to be an immature fault—lacking the clear surface expression of major mapped faults but still capable of producing significant shaking.
The finding could reshape East Coast hazard assessments because the quake, felt by an estimated 42 million people from Virginia to Maine, suggests damaging events can arise outside well-known fault systems near dense population centers.