Earthquake · reviewed by a seismologist
M 1.7md
Earthquake near Clayton, CA
No earthquake was likely felt in Clayton in the 24 hours to 4:40 am PST (12:40 UTC). The last one was M 2.1, 11 km (7 mi) W, at 4:05 am PST on 8 November 2026, estimated intensity II (weak) in town; 3 felt reports to USGS. Every earthquake near Clayton
This page: a magnitude 1.7 earthquake was recorded 9 km (6 mi) east-southeast of Clayton, CA, at 8:42 pm PDT on 19 April 2023 (03:42 UTC), 11 km deep. 5 people have reported feeling it to USGS.
USGS: 9km ESE of Clayton, CA
7 km (5 mi) SSW of Antioch, CA
- When
- 8:42 pm PDT on 19 April 2023 ()
- Where
- 9 km (6 mi) east-southeast of Clayton, CA · earthquakes near Clayton
- Magnitude
- M 1.7 (md)
- Depth
- 11 km below the surface
- Felt
- 5 reports · strongest reported intensity III
- Nearest
- Contra Costa County, 10 km W
- Nearest mapped fault
- Greenville fault, 4 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 1302 days ago
Earthquake alerts for Clayton, CA
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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 6 km (4 mi) from the epicentre. In Clayton, 9 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.
Earthquakes near other towns within 30 km: Antioch, Brentwood, Pittsburg, Blackhawk, Oakley, Diablo.
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 1,300,000× the energy of this one
- Magna, Utah 2020 M 5.7 900,000× the energy of this one
- Around the size people start to feel M 3.0 80× 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
The largest earthquake within 50 km since 2016 was M 4.5 on 2019-10-15 — about 12,000 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 · 11 km SSE of this epicentre
- 5.4 South of Elmira, California · 43 km N of this epicentre
- 5.4 9 km NE of Livermore, California · 22 km SSE of this epicentre
- 5.1 11 km E of Blackhawk, California · 13 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 37.9203, -121.8352. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Contra Costa County, CA | 10 km (6 mi) | W | earthquakes near Contra Costa County |
| Alameda County, CA | 31 km (19 mi) | SSW | earthquakes near Alameda County |
| Solano County, CA | 40 km (25 mi) | NNW | earthquakes near Solano County |
| San Joaquin County, CA | 49 km (31 mi) | E | earthquakes near San Joaquin County |
| Sacramento County, CA | 73 km (45 mi) | NE | earthquakes near Sacramento County |
| San Mateo County, CA | 73 km (46 mi) | SW | earthquakes near San Mateo County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
54 earthquakes have been recorded within 50 km since this one.
- 3.0 2 km NW of Alamo, CA
- 1.5 8 km SE of Sunol, CA
- 2.2 7 km SW of Brentwood, CA
- 2.6 8 km SW of Brentwood, CA
- 1.6 5 km E of Vallejo, CA
- 1.6 2 km NW of Pittsburg, CA
- 1.5 8 km NE of Milpitas, CA
- 2.3 9 km NE of Milpitas, CA
- 2.2 3 km N of Vallejo, CA
- 2.7 3 km N of Piedmont, CA
- 1.8 9 km E of Blackhawk, CA
- 1.6 6 km E of Vallejo, CA
- 1.9 12 km NE of Milpitas, CA
- 2.1 3 km NW of Castro Valley, CA
- 2.1 5 km ESE of Oakland, 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.