QuakeIndex

Earthquake · reviewed by a seismologist

M 2.6md

Earthquake near Alamo, CA

USGS: 2 km SSW of Alamo, California

18 km (11 mi) ENE of Oakland, CA · 8 km (5 mi) S of Walnut Creek, CA

11:45 am PST, Jan 7, 2017 · · 6.7 km deep · released about 280 lb of TNT

Every earthquake near Alamo Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 13 kmAlameda County 23 kmSolano County 49 kmSan Mateo County 55 kmMarin County 66 kmSan Joaquin County 69 kmSanta Clara County 75 kmNapa County 79 kmSan Francisco County 88 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
11:45 am PST on 7 January 2017 ()
Where
2 km (1 mi) SSW of Alamo, CA · earthquakes near Alamo
Magnitude
M 2.6 (md)
Depth
6.7 km below the surface
Felt
42 reports · strongest reported intensity IV
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 3550 days ago

A magnitude 2.6 earthquake was recorded 2 km (1 mi) SSW of Alamo, CA, at 11:45 am PST on 7 January 2017 (19:45 UTC). 42 people have reported feeling it to USGS. This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

Earthquakes near other towns within 30 km: Danville, Saranap, Diablo, Moraga, San Ramon, Walnut Creek.

How big was it?

This earthquake released about 280 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 55,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 39,000× the energy of this one
  3. Around the size people start to feel M 3.0 3.5× the energy of this one
  4. This earthquake M 2.6 about 280 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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record lists 6 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.9 The 1906 San Francisco, California Earthquake · 46 km WSW of this epicentre
  2. 6.0 The 2014 South Napa, California Earthquake · 49 km NNW of this epicentre
  3. 5.8 The 1980 Livermore, California Earthquake · 24 km E of this epicentre
  4. 5.4 9 km NE of Livermore, California · 31 km ESE of this epicentre
  5. 5.3 The 1957 San Francisco, California Earthquake · 43 km WSW 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 37.8320, -122.0418. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Contra Costa County, CA 13 km (8 mi) NE earthquakes near Contra Costa County
Alameda County, CA 23 km (15 mi) SSE earthquakes near Alameda County
Solano County, CA 49 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 66 km (41 mi) WNW earthquakes near Marin County
San Joaquin County, CA 69 km (43 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

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

  1. 2.0 11 km NNW of Pittsburg, California
  2. 1.9 12 km NNE of Bay Point, California
  3. 2.1 10 km N of Bay Point, California
  4. 1.5 5 km ESE of Fremont, California
  5. 1.9 1 km NNE of Pacifica, California
  6. 1.7 4 km SW of Broadmoor, California
  7. 1.6 4 km SW of Broadmoor, California
  8. 1.8 4 km SW of Broadmoor, California
  9. 2.3 9 km ENE of Blackhawk, California
  10. 1.5 2 km SSW of Broadmoor, California
  11. 2.4 4 km ESE of Clayton, California
  12. 1.7 2 km ENE of Pacifica, California
  13. 1.9 1 km W of Diablo, California
  14. 1.6 1 km W of Diablo, California
  15. 1.5 0 km SE of Green Valley, California

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.