Earthquake · reviewed by a seismologist
M 3.1mb_lg
Earthquake near Marlboro, NJ
No earthquake was likely felt in Marlboro in the 24 hours to 7:35 pm EST (00:35 UTC). The last one was M 3.0, 62 km (39 mi) NNE, at 10:18 pm EDT on 2 August 2025, estimated intensity II (weak) in town; 11,128 felt reports to USGS. Every earthquake near Marlboro
This page: a magnitude 3.1 earthquake was recorded 4 km (2 mi) west-southwest of Marlboro, NJ, at 2:00 am EDT on 9 September 2020 (06:00 UTC), 5.6 km deep. 4,459 people have reported feeling it to USGS.
USGS: 3 km WSW of Marlboro, New Jersey
50 km (31 mi) SW of New York, NY · 24 km (15 mi) S of Perth Amboy, NJ
- When
- 2:00 am EDT on 9 September 2020 ()
- Where
- 4 km (2 mi) west-southwest of Marlboro, NJ · earthquakes near Marlboro
- New Jersey today
- every earthquake in New Jersey in the last 24 hours
- Magnitude
- M 3.1 (mb_lg)
- Depth
- 5.6 km below the surface
- Felt
- 4,459 reports · strongest reported intensity V
- Measured shaking
- intensity IV (ShakeMap)
- USGS impact alert
- green
- Nearest
- Monmouth County, 12 km E
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 950 days ago
Earthquake alerts for Marlboro, NJ
Get a notification in this browser when USGS records an earthquake near Marlboro, NJ. No account or email needed.
Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.
At this magnitude and depth, people at rest would likely notice it out to about 128 km (80 mi) from the epicentre. In Marlboro, 4 km away, the estimate is intensity III (weak). Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.
Earthquakes near other towns within 30 km: East Freehold, Yorketown, Freehold, Robertsville, Englishtown, West Freehold.
How big was it?
This earthquake released about 1,300 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.1 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 250,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 11,000× the energy of this one
- Magna, Utah 2020 M 5.7 7,900× the energy of this one
- This earthquake M 3.1 about 1,300 lb of TNT
- Around the size people start to feel M 3.0 this one released 1.4× more
Energy from the Gutenberg–Richter relation (log10E = 1.5M + 4.8), rounded to two figures; bar length is magnitude, which is already a logarithm of energy. Magnitudes of past earthquakes from the USGS catalogue.
For this area
No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.
Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.
Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.
Where
Epicentre 40.3023, -74.2892. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Monmouth County, NJ | 12 km (7 mi) | E | earthquakes near Monmouth County |
| Middlesex County, NJ | 18 km (11 mi) | NNW | earthquakes near Middlesex County |
| Richmond County, NY | 31 km (20 mi) | NNE | earthquakes near Richmond County |
| Mercer County, NJ | 35 km (22 mi) | W | earthquakes near Mercer County |
| Union County, NJ | 40 km (25 mi) | N | earthquakes near Union County |
| Somerset County, NJ | 41 km (25 mi) | NW | earthquakes near Somerset County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
2 earthquakes have been recorded within 50 km since this one.
Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of . QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.
On USGS
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.