QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7md

Earthquake near Diablo, CA

No earthquake was likely felt in Diablo in the 24 hours to 3:14 am PST (11:14 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 1.7 earthquake was recorded 4 km (3 mi) north-northeast of Diablo, CA, at 5:49 pm PDT on 26 April 2026 (00:49 UTC), 9.7 km deep.

USGS: 4 km NNE of Diablo, CA

10 km (6 mi) ESE of Walnut Creek, CA · 44 km (27 mi) ENE of San Francisco, CA

5:49 pm PDT, Apr 26, 2026 · · 9.7 km deep · released about 11 lb of TNT

Every earthquake near Diablo Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 6 kmAlameda County 25 kmSolano County 44 kmSan Joaquin County 59 kmSan Mateo County 63 kmMarin County 74 kmSanta Clara County 75 kmNapa County 79 kmSacramento County 83 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
5:49 pm PDT on 26 April 2026 ()
Where
4 km (3 mi) north-northeast of Diablo, CA · earthquakes near Diablo
Magnitude
M 1.7 (md)
Depth
9.7 km below the surface
Felt
no reports yet
Nearest
Contra Costa County, 6 km NNW
Nearest mapped fault
Greenville fault, 6 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 197 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 8 km (5 mi) from the epicentre. In Diablo, 4 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: Danville 8 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 11 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,300,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 930,000× the energy of this one
  3. Around the size people start to feel M 3.0 83× the energy of this one
  4. This earthquake M 1.7 about 11 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 13,000 times the energy of this one.

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

  1. 5.8 The 1980 Livermore, California Earthquake · 15 km ESE of this epicentre
  2. 5.7 15 km NE of East Foothills, California · 49 km SSE of this epicentre
  3. 5.4 South of Elmira, California · 48 km N of this epicentre
  4. 5.4 9 km NE of Livermore, California · 24 km ESE of this epicentre
  5. 5.1 11 km E of Blackhawk, California · 16 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 37.8688, -121.9363. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Contra Costa County, CA 6 km (4 mi) NNW earthquakes near Contra Costa County
Alameda County, CA 25 km (15 mi) S earthquakes near Alameda County
Solano County, CA 44 km (28 mi) N earthquakes near Solano County
San Joaquin County, CA 59 km (36 mi) E earthquakes near San Joaquin County
San Mateo County, CA 63 km (39 mi) SW earthquakes near San Mateo County
Marin County, CA 74 km (46 mi) WNW earthquakes near Marin 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 12 km SE of Sunol, CA
  2. 2.0 2 km ENE of Hayward, CA
  3. 1.6 3 km NE of Millbrae, CA
  4. 1.6 9 km ENE of Blackhawk, CA
  5. 1.7 3 km SW of Clayton, CA
  6. 2.4 2 km NNE of Hayward, CA
  7. 1.8 5 km E of Vallejo, CA
  8. 1.5 3 km E of Alameda, CA
  9. 1.6 2 km SE of Pacheco, CA
  10. 2.1 4 km SE of San Ramon, CA
  11. 1.8 4 km SW of Clayton, CA
  12. 1.5 7 km ESE of Fremont, CA
  13. 1.6 2 km WNW of Walnut Creek, CA
  14. 1.8 5 km ENE of Vallejo, CA
  15. 1.5 2 km NW of Concord, 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.