The U.S. Geological Survey is still investigating a recent 4.8 earthquake in New Jersey, and the aftershocks have been constant—that is, until they stopped five days ago. So far, over 100 aftershocks have been measured by equipment monitoring North Jersey since the initial earthquake on April 8th.
In the days following the main shock, a series of aftershocks occurred, including a 1.6 magnitude tremor with a depth of 8 kilometers in Califon, marking the most recent seismic activity five days ago. This followed closely by a 1.7 magnitude aftershock at a depth of 6 kilometers. In the same week, Califon experienced additional tremors ranging from 1.7 to 1.9 in magnitude, varying in depth from 4 to 10 kilometers. The neighboring town of Bedminster recorded a 1.7 magnitude quake, and Gladstone reported a slightly stronger 2.6 magnitude quake, both at a depth of 10 kilometers.
Two weeks prior, Long Valley and Califon were also centers of seismic activity with magnitudes of 1.5 and 1.6 respectively, and Gladstone experienced a 2.9 magnitude earthquake at a depth of 8 kilometers. These smaller quakes highlight a pattern of frequent, though mostly minor, seismic occurrences in the region.
New Jersey has experienced several significant earthquakes historically. One of the more substantial historical earthquakes occurred in 1783, centered in the western part of the State. Another notable event was the 1927 quake near Readington, which was estimated at around 4.9. Although New Jersey earthquakes typically do not reach the magnitudes seen in more seismically active regions such as California, they serve as reminders of the state’s geological dynamics.
The recent 4.8 magnitude earthquake and its aftershocks are part of this ongoing narrative of New Jersey’s geological activity. While these events are generally not severe, they underscore the importance of preparedness and awareness for residents in seismically active areas.