Another earthquake rattled New Jersey today not far from where a stronger quake hit the Garden State in April. The likely aftershock struck at 7:00 am today from a depth of 5.3 km near Califon, New Jersey. While more than a dozen people reported to USGS that they felt today’s earthquake, due to its weak magnitude -only 1.7- , no damage or injuries occurred nor would be expected.
An earthquake sequence began in northern New Jersey on the morning of April 5, with a magnitude 4.8 earthquake striking near Tewksbury at 10:23 am. Since then, there have been more than 150 additional aftershocks, including two stronger ones; a magnitude 3.7 struck on the evening of the first quake and today, a magnitude 2.9 earthquake struck in nearly the same place at 9:49 am.
Most of the aftershocks have been barely noticeable. But the initial earthquakes did so some damage. In Berkeley Heights, Union County, New Jersey, the Berkeley Heights Fire Department reported that the foundation of a home there failed and that the primary earthquake on April 5 was a contributing factor. A Brooklyn middle school gym was deemed unsafe after a Department of Buildings inspection found cracks inside; the rest of the school at 370 Fountain Avenue was determined to be safe. Dozens of gas and water leaks were reported in the region, leaving people without utilities like power or water.
According to USGS, the April 5, 2024 occurred as a result of oblique reverse and strike-slip faulting at shallow depths in the crust. Although this event did not occur near a plate boundary, such “intraplate” earthquakes can and do occur. “While this earthquake is relatively small globally, earthquakes of this magnitude are commonly widely felt in the eastern United States because of efficient seismic wave propagation in the region,” the USGS said.
Earthquakes in the eastern US are infrequent but not unexpected. Since 1950, 40 other earthquakes of magnitude 3 and larger have occurred within 155 miles of the April 5 earthquake. In that time range, the April 5, 2024, earthquake is the largest. Within 310 miles of the April 5th earthquake, 13 earthquakes of a magnitude 4.5 and larger have been recorded since 1950, the largest being the August 23, 2011, the magnitude 5.8 Mineral, Virginia earthquake which caused substantial damage and was felt throughout the eastern US. The April 5, 2024, earthquake occurred in a region where faults have been previously identified and may be reactivated at any time.
