Northern New Jersey felt the ground move not once but twice in less than a week. A magnitude 2.7 earthquake was recorded just southwest of Hillsdale, NJ, around 12:11 p.m. on August 5, according to the U.S. Geological Survey (USGS). That event followed a magnitude 3.0 quake on August 2, part of an unusual seismic streak for the region.
The August 5 tremor originated roughly seven miles underground and caused light shaking across towns like Newark, Englewood, and Paterson, while also being felt in parts of New York City. Although no damage was reported, the sudden jolt sparked concern—especially because it came just days after the earlier quake.
But it wasn’t just the East Coast feeling rumbles. Just hours later, multiple earthquakes hit off California’s northern coastline, raising questions about whether the events were somehow linked. Around 1 a.m. ET (10 p.m. PT) on August 6, a magnitude 3.4 earthquake occurred about 100 miles west of Ferndale, followed by a 2.9 quake near Petrolia. Both are remote areas near the Cascadia Subduction Zone, one of North America’s most active fault lines.
While the timing seems more than coincidental, experts say the quakes are almost certainly unrelated. Seismic activity on opposite coasts—separated by over 2,500 miles—is generally influenced by completely different fault systems. The East Coast’s earthquakes are usually caused by old, buried faults that occasionally release stress. In contrast, California’s quakes are tied to ongoing tectonic plate movement along the Pacific Rim.
Still, the clustered activity is rare for New Jersey. The state sits far from the edge of a tectonic plate, and significant quakes are uncommon. But as this week has shown, they’re not impossible. Both of the recent NJ quakes had relatively shallow depths, making them more noticeable even at lower magnitudes.
While there’s no scientific evidence to suggest the East and West Coast quakes are connected, the timing highlights how unpredictable, and widespread, earthquake activity can be.
Residents in both states are reminded to take minor quakes seriously, especially in densely populated areas not built with seismic standards in mind.
The New Jersey Digest is a new jersey magazine that has chronicled daily life in the Garden State for over 10 years.