QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6md

Earthquake near Pleasanton, CA

No earthquake was likely felt in Pleasanton in the 24 hours to 2:41 am PST (10:41 UTC). The last one was M 1.9, 9 km (6 mi) W, at 10:32 am PST on 2 November 2026, estimated intensity II (weak) in town. Every earthquake near Pleasanton

This page: a magnitude 1.6 earthquake was recorded 2 km (1 mi) east-southeast of Pleasanton, CA, at 5:57 pm PST on 27 November 2018 (01:57 UTC), 13 km deep.

USGS: 2km ESE of Pleasanton, CA

in Pleasanton, CA · 40 km (25 mi) N of San Jose, CA

5:57 pm PST, Nov 27, 2018 · · 13 km deep · released about 7.3 lb of TNT

10 km30 km60 km120 km N Alameda County 5 kmContra Costa County 30 kmSanta Clara County 51 kmSan Mateo County 53 kmSan Joaquin County 60 kmSolano County 68 kmSanta Cruz County 73 kmStanislaus County 76 kmMarin County 90 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
5:57 pm PST on 27 November 2018 ()
Where
2 km (1 mi) east-southeast of Pleasanton, CA · earthquakes near Pleasanton
Magnitude
M 1.6 (md)
Depth
13 km below the surface
Felt
no reports yet
Nearest
Alameda County, 5 km WSW
Nearest mapped fault
Pleasanton fault, 3 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 2904 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. In Pleasanton, 2 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.

Earthquakes near other towns within 30 km: Livermore, Dublin, Union City, Fremont, Fairview, San Ramon.

How big was it?

This earthquake released about 7.3 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 2,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,500,000× the energy of this one
  3. Around the size people start to feel M 3.0 130× the energy of this one
  4. This earthquake M 1.6 about 7.3 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 15,000 times the energy of this one.

Before 2016, the USGS record lists 8 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.2 Near San Jose, California · 40 km S of this epicentre
  2. 6.2 The 1984 Morgan Hill, California Earthquake · 42 km SSE of this epicentre
  3. 5.8 The 1980 Livermore, California Earthquake · 22 km NNE of this epicentre
  4. 5.7 15 km NE of East Foothills, California · 25 km SE of this epicentre
  5. 5.5 6 km NNE of East Foothills, California · 26 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 37.6575, -121.8527. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Alameda County, CA 5 km (3 mi) WSW earthquakes near Alameda County
Contra Costa County, CA 30 km (19 mi) NNW earthquakes near Contra Costa County
Santa Clara County, CA 51 km (31 mi) SSE earthquakes near Santa Clara County
San Mateo County, CA 53 km (33 mi) WSW earthquakes near San Mateo County
San Joaquin County, CA 60 km (37 mi) ENE earthquakes near San Joaquin County
Solano County, CA 68 km (42 mi) N earthquakes near Solano County

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

Aftershocks so far

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

  1. 1.6 14km ESE of Livermore, CA
  2. 2.0 10km ENE of Blackhawk, CA
  3. 1.9 10km ENE of Blackhawk, CA
  4. 2.2 10km ENE of Blackhawk, CA
  5. 1.9 10km E of Alum Rock, CA
  6. 2.5 16km N of Morgan Hill, CA
  7. 2.9 28km E of Alum Rock, CA
  8. 2.2 10km ENE of Milpitas, CA
  9. 2.6 9km ENE of Milpitas, CA
  10. 2.1 1km N of Pacheco, CA
  11. 2.0 1km N of Pacheco, CA
  12. 1.5 22km ENE of Alum Rock, CA
  13. 2.0 15km E of Seven Trees, CA
  14. 1.6 2km NNW of Danville, CA
  15. 1.8 9km NE of Milpitas, 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.