Earthquake · reviewed by a seismologist
M 1.9md
4km ENE of San Ramon, CA
- When
- Magnitude
- M 1.9 (md)
- Depth
- 8.8 km below the surface
- Felt
- 1 report · strongest reported intensity III
- Nearest
- Contra Costa County, 14 km N
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1405 days ago
This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 1 person has reported feeling it to USGS.
How big was it?
This earthquake released about 19 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 790,000× the energy of this one
- Magna, Utah 2020 M 5.7 560,000× the energy of this one
- Around the size people start to feel M 3.0 50× the energy of this one
- This earthquake M 1.9 about 19 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 37.7932, -121.9383. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction | |
|---|---|---|---|
| Contra Costa County, CA | 14 km (9 mi) | S of here | earthquakes near Contra Costa County |
| Alameda County, CA | 16 km (10 mi) | N of here | earthquakes near Alameda County |
| Solano County, CA | 53 km (33 mi) | S of here | earthquakes near Solano County |
| San Mateo County, CA | 57 km (35 mi) | NE of here | earthquakes near San Mateo County |
| San Joaquin County, CA | 61 km (38 mi) | WSW of here | earthquakes near San Joaquin County |
| Santa Clara County, CA | 67 km (42 mi) | NNW of here | earthquakes near Santa Clara County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
43 earthquakes have been recorded within 50 km since this one.
- 1.9 3km E of Hayward, CA
- 2.0 2km ESE of Berkeley, CA
- 1.5 6km WNW of Sunol, CA
- 1.8 2km SE of Pacheco, CA
- 1.5 2km SE of Pacheco, CA
- 1.6 8km SE of Sunol, CA
- 1.7 2km N of San Leandro, CA
- 1.5 8km SSW of Livermore, CA
- 1.5 8km SSW of Brentwood, CA
- 2.0 2km NE of Danville, CA
- 1.9 2km W of Diablo, CA
- 1.9 2km NE of Danville, CA
- 1.7 9km NE of Blackhawk, CA
- 1.5 3km ESE of San Ramon, CA
- 2.7 3km NE of San Leandro, 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 7,700 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.