QuakeIndex

Earthquake · automatic estimate, may change

M 1.6md

Earthquake near Diablo, CA

No earthquake was likely felt in Diablo in the 24 hours to 1:27 am PST (09:27 UTC). The last one was M 2.5, 18 km (11 mi) NNW, at 1:23 am PST on 2 November 2026, estimated intensity II (weak) in town; 39 felt reports to USGS. Every earthquake near Diablo

This page: a magnitude 1.6 earthquake was recorded in Diablo, CA, at 3:30 am PDT on 31 October 2026 (10:30 UTC), 15 km deep. The magnitude and location are an automatic first estimate and may change.

USGS: 0 km NW of Diablo, CA

8 km (5 mi) NNW of San Ramon, CA · 41 km (25 mi) E of San Francisco, CA

3:30 am PDT, Oct 31, 2026 · · 15 km deep · released about 8.1 lb of TNT

10 km30 km60 km120 km N Contra Costa County 9 kmAlameda County 22 kmSolano County 48 kmSan Mateo County 59 kmSan Joaquin County 61 kmSanta Clara County 72 kmMarin County 73 kmNapa County 81 kmSacramento County 87 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
3:30 am PDT on 31 October 2026 ()
Where
in Diablo, CA · earthquakes near Diablo
Magnitude
M 1.6 (md)
Depth
15 km below the surface
Felt
no reports yet
Nearest
Contra Costa County, 9 km N
Nearest mapped fault
Pleasanton fault, 4 km from its surface trace — near is not the same as on
Status
Automatic — a machine’s first estimate, which may change

USGS · last changed by USGS · we first saw it 12 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth it was probably too small to be felt, even directly above it. 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.

Earthquakes near other towns within 30 km: Danville, Blackhawk, Alamo, San Ramon, Saranap, Clayton.

How big was it?

This earthquake released about 8.1 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,900,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,300,000× the energy of this one
  3. Around the size people start to feel M 3.0 120× the energy of this one
  4. This earthquake M 1.6 about 8.1 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 18,000 times the energy of this one.

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

  1. 5.8 The 1980 Livermore, California Earthquake · 17 km E of this epicentre
  2. 5.7 15 km NE of East Foothills, California · 47 km SSE of this epicentre
  3. 5.5 6 km NNE of East Foothills, California · 48 km SSE of this epicentre
  4. 5.4 9 km NE of Livermore, California · 24 km ESE of this epicentre
  5. 5.3 The 1957 San Francisco, California Earthquake · 50 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 37.8370, -121.9612. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Contra Costa County, CA 9 km (6 mi) N earthquakes near Contra Costa County
Alameda County, CA 22 km (13 mi) SSE earthquakes near Alameda County
Solano County, CA 48 km (30 mi) N earthquakes near Solano County
San Mateo County, CA 59 km (37 mi) SW earthquakes near San Mateo County
San Joaquin County, CA 61 km (38 mi) E earthquakes near San Joaquin County
Santa Clara County, CA 72 km (45 mi) SSE earthquakes near Santa Clara County

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

Aftershocks so far

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

  1. 1.4 3 km ESE of Berkeley, CA
  2. 1.6 6 km E of Santa Venetia, CA
  3. 1.1 1 km SW of Pleasant Hill, CA
  4. 2.1 1 km SSW of Pleasant Hill, CA
  5. 1.9 26 km SE of Livermore, CA
  6. 1.4 0 km ENE of American Canyon, CA
  7. 1.2 3 km SW of Clayton, CA
  8. 2.2 25 km SE of Livermore, CA
  9. 1.8 1 km WNW of Pleasant Hill, CA
  10. 1.8 6 km ENE of Vallejo, CA
  11. 1.7 12 km E of Suisun City, CA
  12. 1.2 2 km WSW of Danville, CA
  13. 1.9 5 km SW of Dublin, CA
  14. 2.5 2 km WNW of Concord, CA
  15. 1.6 3 km E of Berkeley, 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.