Earthquake · reviewed by a seismologist
M 2.5md
Earthquake near Bay Point, CA
No earthquake was likely felt in Bay Point in the 24 hours to 5:08 am PST (13:08 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 2.5 earthquake was recorded 9 km (6 mi) north of Bay Point, CA, at 9:09 am PDT on 27 August 2018 (16:09 UTC), 21 km deep. 4 people have reported feeling it to USGS.
USGS: 9km N of Bay Point, CA
12 km (7 mi) NNW of Pittsburg, CA · 55 km (34 mi) NE of San Francisco, CA
- When
- 9:09 am PDT on 27 August 2018 ()
- Where
- 9 km (6 mi) north of Bay Point, CA · earthquakes near Bay Point
- Magnitude
- M 2.5 (md)
- Depth
- 21 km below the surface
- Felt
- 4 reports · strongest reported intensity II
- Nearest
- Solano County, 18 km N
- Nearest mapped fault
- Concord fault, 15 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 2998 days ago
Earthquake alerts for Bay Point, 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 5 km (3 mi) from the epicentre. In Bay Point, 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: Pittsburg, Suisun, Concord, Vine Hill, Fairfield, Pacheco.
How big was it?
This earthquake released about 140 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.5 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 110,000× the energy of this one
- Magna, Utah 2020 M 5.7 75,000× the energy of this one
- Around the size people start to feel M 3.0 6.7× the energy of this one
- This earthquake M 2.5 about 140 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 4.4 on 2018-01-04 — about 790 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 · 33 km WNW of this epicentre
- 5.8 The 1980 Livermore, California Earthquake · 34 km SSE of this epicentre
- 5.4 South of Elmira, California · 22 km NNE of this epicentre
- 5.4 9 km NE of Livermore, California · 46 km SSE of this epicentre
- 5.1 11 km E of Blackhawk, California · 37 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 38.1102, -121.9555. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Solano County, CA | 18 km (11 mi) | N | earthquakes near Solano County |
| Contra Costa County, CA | 21 km (13 mi) | S | earthquakes near Contra Costa County |
| Alameda County, CA | 52 km (32 mi) | S | earthquakes near Alameda County |
| Napa County, CA | 55 km (34 mi) | NW | earthquakes near Napa County |
| San Joaquin County, CA | 63 km (39 mi) | ESE | earthquakes near San Joaquin County |
| Yolo County, CA | 63 km (39 mi) | N | earthquakes near Yolo 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.
- 1.9 3km N of Piedmont, CA
- 1.8 3km NNW of Piedmont, CA
- 3.4 3km NNW of Piedmont, CA
- 1.8 0km W of Crockett, CA
- 2.0 3km NNE of Fairview, CA
- 2.0 3km ESE of Berkeley, CA
- 2.0 2km W of Orinda, CA
- 2.3 1km NNW of San Pablo, CA
- 1.6 5km SW of Dublin, CA
- 1.7 1km E of Pacheco, CA
- 2.0 3km ENE of San Leandro, CA
- 1.6 5km E of San Ramon, CA
- 1.8 6km SSW of Yountville, CA
- 1.6 8km SW of Napa, CA
- 2.4 2km NW of Pittsburg, 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.