Earthquake · reviewed by a seismologist
M 2.1md
18km W of Westley, CA
- When
- Magnitude
- M 2.1 (md)
- Depth
- 0.1 km below the surface
- Felt
- no reports yet
- Nearest
- Stanislaus County, 35 km E
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 2410 days ago
This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.
How big was it?
This earthquake released about 37 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 410,000× the energy of this one
- Magna, Utah 2020 M 5.7 290,000× the energy of this one
- Around the size people start to feel M 3.0 26× the energy of this one
- This earthquake M 2.1 about 37 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 37.5283, -121.4027. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction | |
|---|---|---|---|
| Stanislaus County, CA | 35 km (22 mi) | W of here | earthquakes near Stanislaus County |
| Santa Clara County, CA | 42 km (26 mi) | NE of here | earthquakes near Santa Clara County |
| San Joaquin County, CA | 47 km (29 mi) | SSW of here | earthquakes near San Joaquin County |
| Alameda County, CA | 47 km (29 mi) | ESE of here | earthquakes near Alameda County |
| Contra Costa County, CA | 65 km (40 mi) | SE of here | earthquakes near Contra Costa County |
| Merced County, CA | 71 km (44 mi) | WNW of here | earthquakes near Merced 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.
- 1.6 16km ESE of Alum Rock, CA
- 1.6 16km E of Seven Trees, CA
- 1.5 1km SSE of Pleasanton, CA
- 1.7 14km N of Morgan Hill, CA
- 1.6 14km SE of Livermore, CA
- 1.6 9km NE of San Martin, CA
- 3.4 8km NE of Alum Rock, CA
- 1.8 4km E of Livermore, CA
- 2.1 8km ENE of Alum Rock, CA
- 1.6 15km E of Seven Trees, CA
- 2.2 13km ESE of Seven Trees, CA
- 1.7 11km E of Alum Rock, CA
- 2.3 11km E of Alum Rock, CA
- 1.5 11km ESE of Alum Rock, CA
- 2.3 11km ESE of Alum Rock, 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 4.3 on 2019-07-16 — it released about 2,400 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.