Earthquake · automatic estimate, may change
M 1.8md
Earthquake near Bay Point, CA
No earthquake was likely felt in Bay Point in the 24 hours to 5:41 am PST (13:41 UTC). The last one was M 2.1, 13 km (8 mi) SW, at 4:05 am PST on 8 November 2026, estimated intensity II (weak) in town; 3 felt reports to USGS. Every earthquake near Bay Point
This page: a magnitude 1.8 earthquake was recorded 5 km (3 mi) southeast of Bay Point, CA, at 2:25 pm PDT on 27 September 2025 (21:25 UTC), 5.0 km deep. The magnitude and location are an automatic first estimate and may change.
USGS: 5 km SE of Bay Point, CA
in Pittsburg, CA · 50 km (31 mi) ENE of San Francisco, CA
- When
- 2:25 pm PDT on 27 September 2025 ()
- Where
- 5 km (3 mi) southeast of Bay Point, CA · earthquakes near Bay Point
- Magnitude
- M 1.8 (md)
- Depth
- 5.0 km below the surface
- Felt
- no reports yet
- Nearest
- Contra Costa County, 9 km SSW
- Nearest mapped fault
- Greenville fault, 4 km from its surface trace — near is not the same as on
- Status
- Automatic — a machine’s first estimate, which may change
USGS · last changed by USGS · we first saw it 411 days ago
Earthquake alerts for Bay Point, CA
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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 Bay Point, 5 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: Pittsburg 5 km, intensity II · Concord 10 km, intensity II · Antioch 10 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 13 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 1,100,000× the energy of this one
- Magna, Utah 2020 M 5.7 810,000× the energy of this one
- Around the size people start to feel M 3.0 72× the energy of this one
- This earthquake M 1.8 about 13 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 11,000 times the energy of this one.
Before 2016, the USGS record lists 5 earthquakes of M5 or more within 50 km:
- 6.0 The 2014 South Napa, California Earthquake · 42 km NW of this epicentre
- 5.8 The 1980 Livermore, California Earthquake · 22 km SE of this epicentre
- 5.4 South of Elmira, California · 33 km N of this epicentre
- 5.4 9 km NE of Livermore, California · 34 km SE of this epicentre
- 5.1 11 km E of Blackhawk, California · 25 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 38.0002, -121.9238. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Contra Costa County, CA | 9 km (6 mi) | SSW | earthquakes near Contra Costa County |
| Solano County, CA | 30 km (18 mi) | N | earthquakes near Solano County |
| Alameda County, CA | 39 km (24 mi) | S | earthquakes near Alameda County |
| San Joaquin County, CA | 58 km (36 mi) | E | earthquakes near San Joaquin County |
| Napa County, CA | 66 km (41 mi) | NNW | earthquakes near Napa County |
| Sacramento County, CA | 71 km (44 mi) | NE | earthquakes near Sacramento County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
50 earthquakes have been recorded within 50 km since this one.
- 1.7 4 km SE of San Ramon, CA
- 1.6 4 km ESE of San Ramon, CA
- 2.1 4 km SE of San Ramon, CA
- 1.6 4 km SE of San Ramon, CA
- 1.9 4 km SE of San Ramon, CA
- 1.6 3 km SE of San Ramon, CA
- 2.3 3 km SE of San Ramon, CA
- 3.0 4 km SE of San Ramon, CA
- 2.9 4 km SE of San Ramon, CA
- 2.3 4 km SE of San Ramon, CA
- 3.0 4 km SE of San Ramon, CA
- 3.8 3 km SE of San Ramon, CA
- 1.7 6 km ENE of Vallejo, CA
- 1.6 10 km ESE of Black Point-Green Point, CA
- 1.6 5 km SE 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.