Earthquake · reviewed by a seismologist
M 2.7md
Earthquake near Bay Point, CA
No earthquake was likely felt in Bay Point in the 24 hours to 5:26 am PST (13:26 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 2.7 earthquake was recorded 7 km (4 mi) north-northeast of Bay Point, CA, at 4:21 am PDT on 22 September 2018 (11:21 UTC), 23 km deep. 7 people have reported feeling it to USGS.
USGS: 7km NNE of Bay Point, CA
9 km (6 mi) NNW of Pittsburg, CA · 54 km (34 mi) NE of San Francisco, CA
- When
- 4:21 am PDT on 22 September 2018 ()
- Where
- 7 km (4 mi) north-northeast of Bay Point, CA · earthquakes near Bay Point
- Magnitude
- M 2.7 (md)
- Depth
- 23 km below the surface
- Felt
- 7 reports · strongest reported intensity III
- Nearest
- Contra Costa County, 19 km S
- Nearest mapped fault
- Greenville fault, 13 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 2967 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 small earthquake. Shaking like this is often felt indoors nearby and very rarely causes 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, 7 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 8 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 350 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.7 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 43,000× the energy of this one
- Magna, Utah 2020 M 5.7 31,000× the energy of this one
- Around the size people start to feel M 3.0 2.7× the energy of this one
- This earthquake M 2.7 about 350 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 320 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 · 35 km WNW of this epicentre
- 5.8 The 1980 Livermore, California Earthquake · 32 km SSE of this epicentre
- 5.4 South of Elmira, California · 24 km N of this epicentre
- 5.4 9 km NE of Livermore, California · 43 km SSE of this epicentre
- 5.1 11 km E of Blackhawk, California · 34 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 38.0887, -121.9417. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Contra Costa County, CA | 19 km (12 mi) | S | earthquakes near Contra Costa County |
| Solano County, CA | 20 km (12 mi) | N | earthquakes near Solano County |
| Alameda County, CA | 49 km (31 mi) | S | earthquakes near Alameda County |
| Napa County, CA | 57 km (36 mi) | NW | earthquakes near Napa County |
| San Joaquin County, CA | 61 km (38 mi) | ESE | earthquakes near San Joaquin County |
| Yolo County, CA | 66 km (41 mi) | N | earthquakes near Yolo 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.
- 2.1 1km N of Vine Hill, CA
- 1.5 3km S of Crockett, CA
- 2.0 2km S of Discovery Bay, CA
- 3.4 3km NNW of Piedmont, CA
- 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 ENE of Hayward, 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
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.