QuakeIndex

Earthquake · reviewed by a seismologist

M 1.9md

Earthquake near Alamo, CA

No earthquake was likely felt in Alamo in the 24 hours to 4:05 am PST (12:05 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 1.9 earthquake was recorded 6 km (4 mi) northeast of Alamo, CA, at 12:28 am PDT on 10 July 2026 (07:28 UTC), 11 km deep.

USGS: 6 km NE of Alamo, CA

in Walnut Creek, CA · 40 km (25 mi) ENE of San Francisco, CA

12:28 am PDT, Jul 10, 2026 · · 11 km deep · released about 21 lb of TNT

Every earthquake near Alamo Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 4 kmAlameda County 28 kmSolano County 42 kmSan Mateo County 63 kmSan Joaquin County 63 kmMarin County 69 kmNapa County 74 kmSanta Clara County 79 kmSacramento County 84 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
12:28 am PDT on 10 July 2026 ()
Where
6 km (4 mi) northeast of Alamo, CA · earthquakes near Alamo
Magnitude
M 1.9 (md)
Depth
11 km below the surface
Felt
no reports yet
Nearest
Contra Costa County, 4 km NE
Nearest mapped fault
Calaveras fault, 7 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 114 days ago

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 10 km (6 mi) from the epicentre. In Alamo, 6 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 6 km, intensity II · Walnut Creek 7 km, intensity II · Danville 8 km, intensity II · Pleasant Hill 9 km, intensity II · Concord 10 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 21 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.

  1. Mineral, Virginia 2011 M 5.8 730,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 520,000× the energy of this one
  3. Around the size people start to feel M 3.0 46× the energy of this one
  4. This earthquake M 1.9 about 21 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 7,200 times the energy of this one.

Before 2016, the USGS record lists 5 earthquakes of M5 or more within 50 km:

  1. 6.0 The 2014 South Napa, California Earthquake · 45 km NW of this epicentre
  2. 5.8 The 1980 Livermore, California Earthquake · 20 km ESE of this epicentre
  3. 5.4 South of Elmira, California · 46 km N of this epicentre
  4. 5.4 9 km NE of Livermore, California · 30 km ESE of this epicentre
  5. 5.1 11 km E of Blackhawk, California · 21 km ESE 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 37.8942, -121.9907. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Contra Costa County, CA 4 km (3 mi) NE earthquakes near Contra Costa County
Alameda County, CA 28 km (18 mi) SSE earthquakes near Alameda County
Solano County, CA 42 km (26 mi) N earthquakes near Solano County
San Mateo County, CA 63 km (39 mi) SSW earthquakes near San Mateo County
San Joaquin County, CA 63 km (39 mi) E earthquakes near San Joaquin County
Marin County, CA 69 km (43 mi) WNW earthquakes near Marin County

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

Aftershocks so far

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

  1. 2.0 9 km ESE of Livermore, CA
  2. 1.7 2 km NNE of Pleasant Hill, CA
  3. 2.0 3 km W of Dublin, CA
  4. 2.2 3 km W of Dublin, CA
  5. 1.6 3 km W of Dublin, CA
  6. 1.9 6 km SW of Antioch, CA
  7. 2.4 3 km WNW of Dublin, CA
  8. 3.0 9 km SW of Brentwood, CA
  9. 2.5 9 km SW of Brentwood, CA
  10. 3.1 9 km ENE of Blackhawk, CA
  11. 1.6 8 km WSW of Mountain House, CA
  12. 2.1 3 km WNW of Dublin, CA
  13. 2.1 3 km W of Dublin, CA
  14. 2.1 3 km W of Dublin, CA
  15. 2.5 2 km ESE of Oakland, 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.