QuakeIndex

Earthquake · reviewed by a seismologist

M 2.9md

Earthquake near Alamo, CA

No earthquake was likely felt in Alamo in the 24 hours to 1:33 am PST (09:33 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 2.9 earthquake was recorded 6 km (4 mi) south-southwest of Alamo, CA, at 6:10 pm PDT on 15 May 2025 (01:10 UTC), 7.6 km deep. 197 people have reported feeling it to USGS.

USGS: 6 km SW of Alamo, CA

15 km (9 mi) ENE of Oakland, CA · 11 km (7 mi) SSW of Walnut Creek, CA

6:10 pm PDT, May 15, 2025 · · 7.6 km deep · released about 680 lb of TNT

Every earthquake near Alamo Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 16 kmAlameda County 22 kmSan Mateo County 51 kmSolano County 53 kmMarin County 66 kmSan Joaquin County 71 kmSanta Clara County 73 kmNapa County 81 kmSan Francisco County 85 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
6:10 pm PDT on 15 May 2025 ()
Where
6 km (4 mi) south-southwest of Alamo, CA · earthquakes near Alamo
Magnitude
M 2.9 (md)
Depth
7.6 km below the surface
Felt
197 reports · strongest reported intensity V
Nearest
Contra Costa County, 16 km NE
Nearest mapped fault
Calaveras fault, 4 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 475 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 31 km (19 mi) from the epicentre. In Alamo, 6 km away, the estimate is intensity III (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 6 km, intensity III · Danville 6 km, intensity III · San Ramon 8 km, intensity III · Lafayette 10 km, intensity III · Walnut Creek 11 km, intensity III · San Leandro 12 km, intensity III · Castro Valley 13 km, intensity III · Orinda 13 km, intensity III. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 680 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 22,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 16,000× the energy of this one
  3. Around the size people start to feel M 3.0 1.4× the energy of this one
  4. This earthquake M 2.9 about 680 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 220 times the energy of this one.

Before 2016, the USGS record lists 7 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.9 The 1906 San Francisco, California Earthquake · 43 km W of this epicentre
  2. 5.8 The 1980 Livermore, California Earthquake · 26 km E of this epicentre
  3. 5.7 15 km NE of East Foothills, California · 49 km SE of this epicentre
  4. 5.5 6 km NNE of East Foothills, California · 49 km SSE of this epicentre
  5. 5.4 9 km NE of Livermore, California · 32 km E 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 37.8055, -122.0653. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Contra Costa County, CA 16 km (10 mi) NE earthquakes near Contra Costa County
Alameda County, CA 22 km (14 mi) SE earthquakes near Alameda County
San Mateo County, CA 51 km (32 mi) SSW earthquakes near San Mateo County
Solano County, CA 53 km (33 mi) NNE earthquakes near Solano County
Marin County, CA 66 km (41 mi) WNW earthquakes near Marin County
San Joaquin County, CA 71 km (44 mi) ENE earthquakes near San Joaquin County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

58 earthquakes have been recorded within 50 km since this one.

  1. 2.0 2 km E of Hayward, CA
  2. 1.5 1 km SW of Vallejo, CA
  3. 1.7 5 km WSW of Antioch, CA
  4. 1.6 2 km E of Berkeley, CA
  5. 2.0 6 km SSE of Moraga, CA
  6. 1.6 6 km SW of Clayton, CA
  7. 1.6 1 km NNW of Pleasant Hill, CA
  8. 1.9 1 km E of Hayward, CA
  9. 2.0 9 km ENE of Milpitas, CA
  10. 1.6 5 km WSW of San Francisco Zoo, CA
  11. 2.4 2 km ESE of Berkeley, CA
  12. 1.7 1 km S of East Richmond Heights, CA
  13. 2.1 6 km ENE of Vallejo, CA
  14. 1.9 11 km SSE of Livermore, CA
  15. 2.0 2 km SSE of Danville, 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

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.