Earthquake · reviewed by a seismologist
M 1.7md
Earthquake near Oakley, CA
No earthquake was likely felt in Oakley in the 24 hours to 2:42 am PST (10:42 UTC). The last one was M 3.0, 16 km (10 mi) SSW, at 6:47 am PDT on 14 September 2026, estimated intensity II (weak) in town; 52 felt reports to USGS. Every earthquake near Oakley
This page: a magnitude 1.7 earthquake was recorded in Oakley, CA, at 11:53 pm PDT on 21 June 2018 (06:53 UTC), 10 km deep. 2 people have reported feeling it to USGS.
USGS: 1km SE of Oakley, CA
8 km (5 mi) E of Antioch, CA · 6 km (4 mi) NNE of Brentwood, CA
- When
- 11:53 pm PDT on 21 June 2018 ()
- Where
- in Oakley, CA · earthquakes near Oakley
- Magnitude
- M 1.7 (md)
- Depth
- 10 km below the surface
- Felt
- 2 reports · strongest reported intensity II
- Nearest
- Contra Costa County, 23 km WSW
- Nearest mapped fault
- Greenville fault, 18 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 3064 days ago
Earthquake alerts for Oakley, CA
Get a notification in this browser when USGS records an earthquake near Oakley, 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 8 km (5 mi) from the epicentre. 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: Oakley in town, intensity II · Brentwood 7 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 12 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 1,200,000× the energy of this one
- Magna, Utah 2020 M 5.7 870,000× the energy of this one
- Around the size people start to feel M 3.0 78× the energy of this one
- This earthquake M 1.7 about 12 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
No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.
Before 2016, the USGS record lists 4 earthquakes of M5 or more within 50 km:
- 5.8 The 1980 Livermore, California Earthquake · 18 km SSW of this epicentre
- 5.4 South of Elmira, California · 38 km NNW of this epicentre
- 5.4 9 km NE of Livermore, California · 27 km S of this epicentre
- 5.1 11 km E of Blackhawk, California · 21 km SSW 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 37.9925, -121.7045. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Contra Costa County, CA | 23 km (14 mi) | WSW | earthquakes near Contra Costa County |
| Solano County, CA | 37 km (23 mi) | NW | earthquakes near Solano County |
| San Joaquin County, CA | 38 km (24 mi) | E | earthquakes near San Joaquin County |
| Alameda County, CA | 43 km (26 mi) | SSW | earthquakes near Alameda County |
| Sacramento County, CA | 60 km (37 mi) | NNE | earthquakes near Sacramento County |
| Stanislaus County, CA | 78 km (48 mi) | SE | earthquakes near Stanislaus County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
53 earthquakes have been recorded within 50 km since this one.
- 1.6 4km NE of Vallejo, CA
- 1.8 2km NE of San Ramon, CA
- 2.0 14km N of Pittsburg, CA
- 2.2 1km NNW of Alamo, CA
- 1.6 2km SW of Diablo, CA
- 1.5 3km ESE of Berkeley, CA
- 1.7 3km NW of Diablo, CA
- 2.3 16km SSE of Livermore, CA
- 1.6 4km NNW of San Leandro, CA
- 1.8 6km ESE of San Ramon, CA
- 1.6 6km ESE of San Ramon, CA
- 1.6 9km WSW of Brentwood, CA
- 1.9 2km N of San Leandro, CA
- 1.8 2km E of San Leandro, CA
- 1.8 11km ESE of Sunol, 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.