Earthquake · reviewed by a seismologist
M 1.9md
Earthquake near Bethel Island, CA
No earthquake was likely felt in Bethel Island in the 24 hours to 1:04 am PST (09:04 UTC). The last one was M 3.0, 22 km (13 mi) SW, at 6:47 am PDT on 14 September 2026, estimated intensity II (weak) in town; 52 felt reports to USGS. Every earthquake near Bethel Island
This page: a magnitude 1.9 earthquake was recorded 7 km (4 mi) east-southeast of Bethel Island, CA, at 8:33 pm PST on 20 November 2021 (04:33 UTC), 8.9 km deep.
USGS: 7km ESE of Bethel Island, CA
23 km (15 mi) W of Stockton, CA · 14 km (8 mi) ENE of Brentwood, CA
- When
- 8:33 pm PST on 20 November 2021 ()
- Where
- 7 km (4 mi) east-southeast of Bethel Island, CA · earthquakes near Bethel Island
- Magnitude
- M 1.9 (md)
- Depth
- 8.9 km below the surface
- Felt
- no reports yet
- Nearest
- San Joaquin County, 27 km ESE
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1809 days ago
Earthquake alerts for Bethel Island, CA
Get a notification in this browser when USGS records an earthquake near Bethel Island, 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 12 km (7 mi) from the epicentre. In Bethel Island, 7 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: Discovery Bay 9 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 21 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 730,000× the energy of this one
- Magna, Utah 2020 M 5.7 520,000× the energy of this one
- Around the size people start to feel M 3.0 46× the energy of this one
- This earthquake M 1.9 about 21 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 2019-10-15 — about 7,200 times the energy of this one.
Before 2016, the USGS record lists 4 earthquakes of M5 or more within 50 km:
- 5.8 The 1980 Livermore, California Earthquake · 23 km SW of this epicentre
- 5.4 South of Elmira, California · 45 km NW of this epicentre
- 5.4 9 km NE of Livermore, California · 28 km SSW of this epicentre
- 5.1 11 km E of Blackhawk, California · 26 km SW 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 37.9840, -121.5765. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| San Joaquin County, CA | 27 km (17 mi) | ESE | earthquakes near San Joaquin County |
| Contra Costa County, CA | 34 km (21 mi) | WSW | earthquakes near Contra Costa County |
| Solano County, CA | 45 km (28 mi) | NW | earthquakes near Solano County |
| Alameda County, CA | 48 km (30 mi) | SW | earthquakes near Alameda County |
| Sacramento County, CA | 56 km (35 mi) | NNE | earthquakes near Sacramento County |
| Stanislaus County, CA | 69 km (43 mi) | SE | earthquakes near Stanislaus County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
51 earthquakes have been recorded within 50 km since this one.
- 1.8 3km NNE of San Ramon, CA
- 1.7 3km S of Diablo, CA
- 2.4 8km SW of Brentwood, CA
- 2.3 10km SW of Brentwood, CA
- 1.6 10km ENE of Blackhawk, CA
- 1.8 3km S of Pittsburg, CA
- 1.9 5km ESE of Moraga, CA
- 2.7 4km S of Pittsburg, CA
- 1.9 6km SW of Clayton, CA
- 1.6 4km SW of San Ramon, CA
- 1.6 4km SW of San Ramon, CA
- 1.6 2km E of Pleasant Hill, CA
- 1.7 10km ESE of Clayton, CA
- 2.0 9km NE of Blackhawk, CA
- 2.0 2km E of Pacheco, 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.