Earthquake · reviewed by a seismologist
M 1.8md
Earthquake near Black Point-Green Point, CA
No earthquake was likely felt in Black Point-Green Point in the 24 hours to 4:08 pm PST (00:08 UTC). The last one was M 2.4, 6 km (4 mi) WSW, at 6:21 pm PDT on 26 September 2026, estimated intensity II (weak) in town. Every earthquake near Black Point-Green Point
This page: a magnitude 1.8 earthquake was recorded 10 km (6 mi) east-southeast of Black Point-Green Point, CA, at 1:14 pm PDT on 24 August 2023 (20:14 UTC), 11 km deep.
USGS: 10 km ESE of Black Point-Green Point, CA
13 km (8 mi) E of Novato, CA · 34 km (21 mi) N of San Francisco, CA
- When
- 1:14 pm PDT on 24 August 2023 ()
- Where
- 10 km (6 mi) east-southeast of Black Point-Green Point, CA · earthquakes near Black Point-Green Point
- Magnitude
- M 1.8 (md)
- Depth
- 11 km below the surface
- Felt
- no reports yet
- Nearest
- Marin County, 30 km W
- Nearest mapped fault
- Rodgers Creek fault, 8 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 1175 days ago
Earthquake alerts for Black Point-Green 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 9 km (6 mi) from the epicentre. In Black Point-Green Point, 10 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: Montalvin, Hercules, Tara Hills, Pinole, Vallejo, Rodeo.
How big was it?
This earthquake released about 17 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 5.8 870,000× the energy of this one
- Magna, Utah 2020 M 5.7 620,000× the energy of this one
- Around the size people start to feel M 3.0 55× the energy of this one
- This earthquake M 1.8 about 17 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 8,500 times the energy of this one.
Before 2016, the USGS record lists 5 earthquakes of M5 or more within 50 km:
- 7.9 The 1906 San Francisco, California Earthquake · 39 km SSW of this epicentre
- 6.0 The 2014 South Napa, California Earthquake · 17 km NNE of this epicentre
- 5.3 The 1957 San Francisco, California Earthquake · 47 km S of this epicentre
- 5.3 3 km E of Bloomfield, California · 44 km NW of this epicentre
- 5.3 Northern California · 45 km NW 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 38.0822, -122.4043. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Marin County, CA | 30 km (19 mi) | W | earthquakes near Marin County |
| Contra Costa County, CA | 44 km (27 mi) | ESE | earthquakes near Contra Costa County |
| Solano County, CA | 46 km (28 mi) | ENE | earthquakes near Solano County |
| Napa County, CA | 48 km (30 mi) | N | earthquakes near Napa County |
| Alameda County, CA | 65 km (40 mi) | SE | earthquakes near Alameda County |
| Sonoma County, CA | 67 km (42 mi) | NW | earthquakes near Sonoma 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.
- 1.9 7 km ESE of Roseland, CA
- 1.5 5 km E of Vallejo, CA
- 1.7 2 km ESE of Oakland, CA
- 1.7 8 km SSW of Martinez, CA
- 2.5 6 km E of Santa Rosa, CA
- 1.8 6 km E of Santa Rosa, CA
- 1.6 4 km WSW of Colma, CA
- 2.2 6 km WNW of San Francisco Zoo, CA
- 1.5 6 km WNW of San Francisco Zoo, CA
- 2.1 3 km N of San Lorenzo, CA
- 1.6 12 km ENE of Yountville, CA
- 1.6 7 km ESE of Santa Venetia, CA
- 1.9 4 km SSE of Roseland, CA
- 1.6 4 km SSE of Roseland, CA
- 2.5 7 km WSW of Kenwood, 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.