QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1md

Earthquake near Dublin, CA

No earthquake was likely felt in Dublin in the 24 hours to 3:39 am PST (11:39 UTC). The last one was M 1.9, 5 km (3 mi) SW, at 10:32 am PST on 2 November 2026, estimated intensity II (weak) in town. Every earthquake near Dublin

This page: a magnitude 2.1 earthquake was recorded 3 km (2 mi) south-southwest of Dublin, CA, at 1:30 pm PDT on 16 August 2018 (20:30 UTC), 8.6 km deep.

USGS: 2km SSW of Dublin, CA

6 km (4 mi) WNW of Pleasanton, CA · 44 km (27 mi) NNW of San Jose, CA

1:30 pm PDT, Aug 16, 2018 · · 8.6 km deep · released about 38 lb of TNT

10 km30 km60 km120 km N Alameda County 5 kmContra Costa County 27 kmSan Mateo County 48 kmSanta Clara County 56 kmSolano County 65 kmSan Joaquin County 65 kmSanta Cruz County 74 kmMarin County 82 kmStanislaus 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
1:30 pm PDT on 16 August 2018 ()
Where
3 km (2 mi) south-southwest of Dublin, CA · earthquakes near Dublin
Magnitude
M 2.1 (md)
Depth
8.6 km below the surface
Felt
no reports yet
Nearest
Alameda County, 5 km SE
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 3008 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 14 km (9 mi) from the epicentre. In Dublin, 3 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: Dublin 3 km, intensity II · Pleasanton 6 km, intensity II · San Ramon 11 km, intensity II · Union City 11 km, intensity II · Hayward 12 km, intensity II · Castro Valley 13 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 38 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 390,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 280,000× the energy of this one
  3. Around the size people start to feel M 3.0 25× the energy of this one
  4. This earthquake M 2.1 about 38 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 4.4 on 2018-01-04 — about 2,900 times the energy of this one.

Before 2016, the USGS record lists 9 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.2 Near San Jose, California · 44 km SSE of this epicentre
  2. 6.2 The 1984 Morgan Hill, California Earthquake · 47 km SSE of this epicentre
  3. 5.8 The 1980 Livermore, California Earthquake · 24 km NE of this epicentre
  4. 5.7 15 km NE of East Foothills, California · 32 km SE of this epicentre
  5. 5.5 6 km NNE of East Foothills, California · 31 km SSE 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 37.6803, -121.9442. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Alameda County, CA 5 km (3 mi) SE earthquakes near Alameda County
Contra Costa County, CA 27 km (17 mi) N earthquakes near Contra Costa County
San Mateo County, CA 48 km (30 mi) SW earthquakes near San Mateo County
Santa Clara County, CA 56 km (35 mi) SSE earthquakes near Santa Clara County
Solano County, CA 65 km (41 mi) N earthquakes near Solano County
San Joaquin County, CA 65 km (41 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. 2.8 6km WNW of Mountain House, CA
  2. 2.5 3km ESE of San Leandro, CA
  3. 2.1 15km E of Seven Trees, CA
  4. 1.5 16km SSE of Livermore, CA
  5. 1.7 2km E of Hayward, CA
  6. 1.9 11km SSE of Portola Valley, CA
  7. 1.6 2km W of Diablo, CA
  8. 2.7 8km ENE of Alum Rock, CA
  9. 1.5 3km S of Loyola, CA
  10. 2.5 9km E of Alum Rock, CA
  11. 2.8 15km ENE of Alum Rock, CA
  12. 1.8 2km NE of San Ramon, CA
  13. 1.5 7km SSE of Portola Valley, CA
  14. 1.8 7km SSE of Portola Valley, CA
  15. 2.2 1km NNW of Alamo, 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.