Earthquake · reviewed by a seismologist
M 2.3md
2km WNW of Concord, CA
- When
- Magnitude
- M 2.3 (md)
- Depth
- 17 km below the surface
- Felt
- 4 reports · strongest reported intensity II
- Nearest
- Contra Costa County, 9 km SE
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1873 days ago
This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 4 people have reported feeling it to USGS.
How big was it?
This earthquake released about 82 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 180,000× the energy of this one
- Magna, Utah 2020 M 5.7 130,000× the energy of this one
- Around the size people start to feel M 3.0 12× the energy of this one
- This earthquake M 2.3 about 82 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.
Where
Epicentre 37.9735, -122.0323. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction | |
|---|---|---|---|
| Contra Costa County, CA | 9 km (6 mi) | NW of here | earthquakes near Contra Costa County |
| Solano County, CA | 34 km (21 mi) | SSW of here | earthquakes near Solano County |
| Alameda County, CA | 38 km (23 mi) | NNW of here | earthquakes near Alameda County |
| Marin County, CA | 63 km (39 mi) | E of here | earthquakes near Marin County |
| Napa County, CA | 65 km (40 mi) | SSE of here | earthquakes near Napa County |
| San Joaquin County, CA | 67 km (41 mi) | W of here | earthquakes near San Joaquin 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.
- 1.9 1km S of San Ramon, CA
- 1.6 5km SW of Clayton, CA
- 1.6 6km E of Vallejo, CA
- 2.1 3km WNW of Crockett, CA
- 2.1 4km WSW of Alamo, CA
- 2.1 6km SSW of Moraga, CA
- 1.9 5km SW of Pacheco, CA
- 1.8 2km SE of Pacheco, CA
- 1.6 1km S of Blackhawk, CA
- 2.7 0km N of Byron, CA
- 1.5 3km N of San Leandro, CA
- 3.4 3km N of San Leandro, CA
- 3.0 3km N of San Leandro, CA
- 1.6 11km NE of Napa, CA
- 2.1 2km E of Hayward, 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.
For this area
The largest earthquake within 50 km in our catalogue was M 4.5 on 2019-10-15 — it released about 1,800 times the energy of this one.
From the QuakeIndex catalogue, built from the USGS FDSN event service.
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.