Earthquake · reviewed by a seismologist
M 2.1md
Earthquake near East Quincy, CA
No earthquake was likely felt in East Quincy in the 24 hours to 11:48 am PST (19:48 UTC). The last one was M 2.3, 6 km (3 mi) N, at 5:11 am PST on 7 November 2026, estimated intensity II (weak) in town. Every earthquake near East Quincy
This page: a magnitude 2.1 earthquake was recorded 14 km (9 mi) east-northeast of East Quincy, CA, at 5:40 pm PDT on 15 August 2021 (00:40 UTC), 6.8 km deep.
USGS: 7km N of Greenhorn, CA
89 km (55 mi) WNW of Reno, NV
- When
- 5:40 pm PDT on 15 August 2021 ()
- Where
- 14 km (9 mi) east-northeast of East Quincy, CA · earthquakes near East Quincy
- Magnitude
- M 2.1 (md)
- Depth
- 6.8 km below the surface
- Felt
- no reports yet
- Nearest
- Plumas County, 8 km WNW
- Nearest mapped fault
- Mohawk Valley fault, 1 km from its surface trace — near is not the same as on
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1913 days ago
Earthquake alerts for East Quincy, CA
Get a notification in this browser when USGS records an earthquake near East Quincy, CA. 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 minor earthquake. Quakes this small are rarely felt and do not cause damage.
At this magnitude and depth, people at rest would likely notice it out to about 15 km (9 mi) from the epicentre. In East Quincy, 14 km away, the estimate is intensity II (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.
Likely felt in: East Quincy 14 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 37 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 410,000× the energy of this one
- Magna, Utah 2020 M 5.7 290,000× the energy of this one
- Around the size people start to feel M 3.0 26× the energy of this one
- This earthquake M 2.1 about 37 lb of TNT
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
The largest earthquake within 50 km since 2016 was M 4.5 on 2016-08-04 — about 4,300 times the energy of this one.
Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:
- 5.7 2 km NNE of Canyondam, California · 37 km NW of this epicentre
- 5.2 3 km N of Blairsden, California · 20 km SSE of this epicentre
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 39.9650, -120.7365. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Plumas County, CA | 8 km (5 mi) | WNW | earthquakes near Plumas County |
| Sierra County, CA | 47 km (29 mi) | SSE | earthquakes near Sierra County |
| Nevada County, CA | 74 km (46 mi) | S | earthquakes near Nevada County |
| Butte County, CA | 81 km (50 mi) | WSW | earthquakes near Butte County |
| Lassen County, CA | 84 km (52 mi) | N | earthquakes near Lassen County |
| Yuba County, CA | 93 km (58 mi) | SW | earthquakes near Yuba County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
49 earthquakes have been recorded within 50 km since this one.
- 1.6 4km N of Canyondam, CA
- 2.1 4km SE of Meadow Valley, CA
- 2.3 5km ENE of East Quincy, CA
- 2.1 16km WSW of Loyalton, CA
- 2.1 16km WSW of Loyalton, CA
- 1.6 16km WSW of Loyalton, CA
- 2.2 15km WSW of Loyalton, CA
- 2.4 16km WSW of Loyalton, CA
- 3.3 16km WSW of Loyalton, CA
- 2.7 16km WSW of Loyalton, CA
- 1.6 2 km WNW of Sierraville, California
- 2.1 16km WSW of Loyalton, CA
- 1.5 5km N of Almanor, CA
- 2.3 10km WNW of Little Grass Valley, CA
- 2.1 3km N of Canyondam, CA
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.