Overview

• The United States Geological Survey recorded seven quakes on July 21, 2025, with magnitudes ranging from 0.7 to 2.0.
• All events occurred at depths near 5 kilometers, forming a localized swarm around Randolph and Mendham.
• The strongest tremor, a magnitude 2.0, struck southeast of Randolph at 9:00 p.m. EDT and was felt as a loud boom in homes.
• The Morris County Office of Emergency Management confirmed there were no injuries or structural damage reported.
• The USGS distinguishes this swarm from aftershocks of the April 2024 magnitude-4.8 quake and says seismic monitoring will continue across the region.