Earthquake · reviewed by a seismologist
M 1.8md
Earthquake near Alamo, CA
No earthquake was likely felt in Alamo in the 24 hours to 10:41 am PST (18:41 UTC). The last one was M 2.1, 11 km (7 mi) NNW, at 4:05 am PST on 8 November 2026, estimated intensity II (weak) in town; 3 felt reports to USGS. Every earthquake near Alamo
This page: a magnitude 1.8 earthquake was recorded 3 km (2 mi) south of Alamo, CA, at 3:29 am PDT on 29 April 2019 (10:29 UTC), 13 km deep.
USGS: 3km S of Alamo, CA
18 km (11 mi) ENE of Oakland, CA · 9 km (5 mi) S of Walnut Creek, CA
- When
- 3:29 am PDT on 29 April 2019 ()
- Where
- 3 km (2 mi) south of Alamo, CA · earthquakes near Alamo
- Magnitude
- M 1.8 (md)
- Depth
- 13 km below the surface
- Felt
- no reports yet
- Nearest
- Contra Costa County, 13 km NE
- Nearest mapped fault
- Calaveras fault, 1 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 2754 days ago
Earthquake alerts for Alamo, CA
Get a notification in this browser when USGS records an earthquake near Alamo, CA. No account or email needed.
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 4 km (2 mi) from the epicentre. In Alamo, 3 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: Alamo 3 km, intensity II · Danville 3 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 16 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 5.8 970,000× the energy of this one
- Magna, Utah 2020 M 5.7 680,000× the energy of this one
- Around the size people start to feel M 3.0 61× the energy of this one
- This earthquake M 1.8 about 16 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 7,200 times the energy of this one.
Before 2016, the USGS record lists 8 earthquakes of M5 or more within 50 km; the five largest:
- 7.9 The 1906 San Francisco, California Earthquake · 46 km W of this epicentre
- 6.0 The 2014 South Napa, California Earthquake · 50 km NNW of this epicentre
- 5.8 The 1980 Livermore, California Earthquake · 23 km E of this epicentre
- 5.7 15 km NE of East Foothills, California · 49 km SE of this epicentre
- 5.5 6 km NNE of East Foothills, California · 49 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 37.8252, -122.0330. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Contra Costa County, CA | 13 km (8 mi) | NE | earthquakes near Contra Costa County |
| Alameda County, CA | 22 km (14 mi) | SSE | earthquakes near Alameda County |
| Solano County, CA | 50 km (31 mi) | N | earthquakes near Solano County |
| San Mateo County, CA | 55 km (34 mi) | SSW | earthquakes near San Mateo County |
| Marin County, CA | 67 km (42 mi) | WNW | earthquakes near Marin County |
| San Joaquin County, CA | 68 km (42 mi) | E | earthquakes near San Joaquin 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 12km ENE of Milpitas, CA
- 2.5 8km NE of Alum Rock, CA
- 1.6 9km NE of Milpitas, CA
- 1.6 2km E of Berkeley, CA
- 1.6 3km ENE of Pittsburg, CA
- 2.0 3km SSW of Alameda, CA
- 2.5 3km N of San Leandro, CA
- 2.0 5km SSE of Pittsburg, CA
- 1.6 4km ESE of Moraga, CA
- 2.4 11km NE of Milpitas, CA
- 1.5 3km NE of Alamo, CA
- 1.8 2km NE of San Ramon, CA
- 1.8 2km NE of San Ramon, CA
- 2.0 9km N of Pittsburg, CA
- 1.5 0km SE of Pacifica, 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.