Earthquake · reviewed by a seismologist
M 1.6md
Earthquake near Hercules, CA
No earthquake was likely felt in Hercules in the 24 hours to 11:24 am PST (19:24 UTC). The last one was M 2.6, 17 km (11 mi) SSE, at 6:23 pm PST on 1 November 2026, estimated intensity II (weak) in town; 114 felt reports to USGS. Every earthquake near Hercules
This page: a magnitude 1.6 earthquake was recorded 3 km (2 mi) northwest of Hercules, CA, at 1:27 am PDT on 17 May 2026 (08:27 UTC), 7.6 km deep.
USGS: 3 km NW of Hercules, CA
9 km (6 mi) SSW of Vallejo, CA · 30 km (19 mi) NNE of San Francisco, CA
- When
- 1:27 am PDT on 17 May 2026 ()
- Where
- 3 km (2 mi) northwest of Hercules, CA · earthquakes near Hercules
- Magnitude
- M 1.6 (md)
- Depth
- 7.6 km below the surface
- Felt
- no reports yet
- Nearest
- Contra Costa County, 34 km ESE
- Nearest mapped fault
- Rodgers Creek fault, 16 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 169 days ago
Earthquake alerts for Hercules, CA
Get a notification in this browser when USGS records an earthquake near Hercules, 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. In Hercules, 3 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: Hercules 3 km, intensity II · Pinole 4 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 6.6 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 2,300,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,600,000× the energy of this one
- Around the size people start to feel M 3.0 140× the energy of this one
- This earthquake M 1.6 about 6.6 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 22,000 times the energy of this one.
Before 2016, the USGS record lists 4 earthquakes of M5 or more within 50 km:
- 7.9 The 1906 San Francisco, California Earthquake · 38 km SSW of this epicentre
- 6.0 The 2014 South Napa, California Earthquake · 20 km N of this epicentre
- 5.4 South of Elmira, California · 46 km NE of this epicentre
- 5.3 The 1957 San Francisco, California Earthquake · 44 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 38.0353, -122.3107. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Contra Costa County, CA | 34 km (21 mi) | ESE | earthquakes near Contra Costa County |
| Marin County, CA | 38 km (24 mi) | W | earthquakes near Marin County |
| Solano County, CA | 41 km (26 mi) | NE | earthquakes near Solano County |
| Napa County, CA | 52 km (33 mi) | N | earthquakes near Napa County |
| Alameda County, CA | 56 km (35 mi) | SE | earthquakes near Alameda County |
| San Mateo County, CA | 69 km (43 mi) | S | earthquakes near San Mateo 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 3 km SW of Clayton, CA
- 1.7 5 km W of Glen Ellen, CA
- 1.9 0 km SSW of Pleasant Hill, CA
- 2.1 7 km W of Kenwood, CA
- 2.0 2 km SSW of Alamo, CA
- 1.8 2 km SW of Alamo, CA
- 1.7 2 km ESE of Pacheco, CA
- 1.5 7 km E of Santa Venetia, CA
- 1.9 2 km SE of Oakland, CA
- 2.0 2 km ENE of Berkeley, CA
- 2.6 2 km NNE of San Leandro, CA
- 1.5 3 km SW of Clayton, CA
- 1.8 5 km SE of Napa, CA
- 1.5 2 km ESE of Pacifica, CA
- 1.9 2 km ESE 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.