Earthquake · reviewed by a seismologist
M 1.8md
Earthquake near Pleasanton, CA
No earthquake was likely felt in Pleasanton in the 24 hours to 1:35 pm PST (21:35 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 1.8 earthquake was recorded 4 km (3 mi) northeast of Pleasanton, CA, at 7:55 pm PST on 9 February 2021 (03:55 UTC), 12 km deep.
USGS: 4km NE of Pleasanton, CA
in Pleasanton, CA · 43 km (27 mi) N of San Jose, CA
- When
- 7:55 pm PST on 9 February 2021 ()
- Where
- 4 km (3 mi) northeast of Pleasanton, CA · earthquakes near Pleasanton
- Magnitude
- M 1.8 (md)
- Depth
- 12 km below the surface
- Felt
- no reports yet
- Nearest
- Alameda County, 8 km WSW
- Nearest mapped fault
- Pleasanton fault, 4 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 2101 days ago
Earthquake alerts for Pleasanton, CA
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Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
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 7 km (4 mi) from the epicentre. In Pleasanton, 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: Pleasanton 4 km, intensity II · Livermore 6 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 17 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 900,000× the energy of this one
- Magna, Utah 2020 M 5.7 640,000× the energy of this one
- Around the size people start to feel M 3.0 57× the energy of this one
- This earthquake M 1.8 about 17 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 8,800 times the energy of this one.
Before 2016, the USGS record lists 8 earthquakes of M5 or more within 50 km; the five largest:
- 6.2 Near San Jose, California · 43 km S of this epicentre
- 6.2 The 1984 Morgan Hill, California Earthquake · 44 km SSE of this epicentre
- 5.8 The 1980 Livermore, California Earthquake · 18 km NNE of this epicentre
- 5.7 15 km NE of East Foothills, California · 26 km SSE of this epicentre
- 5.5 6 km NNE of East Foothills, California · 28 km S 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 37.6840, -121.8342. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Alameda County, CA | 8 km (5 mi) | WSW | earthquakes near Alameda County |
| Contra Costa County, CA | 28 km (17 mi) | NNW | earthquakes near Contra Costa County |
| Santa Clara County, CA | 53 km (33 mi) | SSE | earthquakes near Santa Clara County |
| San Mateo County, CA | 56 km (35 mi) | WSW | earthquakes near San Mateo County |
| San Joaquin County, CA | 57 km (35 mi) | ENE | earthquakes near San Joaquin County |
| Solano County, CA | 66 km (41 mi) | N | earthquakes near Solano County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
55 earthquakes have been recorded within 50 km since this one.
- 2.0 10km E of Blackhawk, CA
- 1.8 9km E of Blackhawk, CA
- 1.9 5km NW of Dublin, CA
- 1.6 5km NW of Dublin, CA
- 2.1 6km WNW of Dublin, CA
- 2.2 5km WNW of Dublin, CA
- 2.0 6km WNW of Dublin, CA
- 2.2 5km NW of Dublin, CA
- 1.6 5km NW of Dublin, CA
- 1.9 6km SW of Clayton, CA
- 1.7 2km ESE of Berkeley, CA
- 1.8 2km ESE of Berkeley, CA
- 1.6 16km NE of Alum Rock, CA
- 1.5 4km NW of Dublin, CA
- 1.6 1km ENE of Alameda, 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
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.