Earthquake · reviewed by a seismologist
M 1.9md
Earthquake near Orinda, CA
No earthquake was likely felt in Orinda in the 24 hours to 3:20 am PST (11:20 UTC). The last one was M 2.1, 12 km (8 mi) NE, at 4:05 am PST on 8 November 2026, estimated intensity II (weak) in town; 3 felt reports to USGS. Every earthquake near Orinda
This page: a magnitude 1.9 earthquake was recorded 2 km (2 mi) northwest of Orinda, CA, at 11:58 pm PST on 28 January 2021 (07:58 UTC), 8.3 km deep. 2 people have reported feeling it to USGS.
USGS: 2km NW of Orinda, CA
23 km (14 mi) ENE of San Francisco, CA · 9 km (6 mi) ENE of Berkeley, CA
- When
- 11:58 pm PST on 28 January 2021 ()
- Where
- 2 km (2 mi) northwest of Orinda, CA · earthquakes near Orinda
- Magnitude
- M 1.9 (md)
- Depth
- 8.3 km below the surface
- Felt
- 2 reports · strongest reported intensity II
- Nearest
- Contra Costa County, 22 km E
- Nearest mapped fault
- Hayward fault, 5 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 2113 days ago
Earthquake alerts for Orinda, 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 12 km (7 mi) from the epicentre. In Orinda, 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.
Likely felt in: Orinda 2 km, intensity II · Berkeley 7 km, intensity II · Lafayette 7 km, intensity II · El Cerrito 10 km, intensity II · Oakland 11 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 19 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 810,000× the energy of this one
- Magna, Utah 2020 M 5.7 580,000× the energy of this one
- Around the size people start to feel M 3.0 51× the energy of this one
- This earthquake M 1.9 about 19 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 7,900 times the energy of this one.
Before 2016, the USGS record lists 6 earthquakes of M5 or more within 50 km; the five largest:
- 7.9 The 1906 San Francisco, California Earthquake · 34 km WSW of this epicentre
- 6.0 The 2014 South Napa, California Earthquake · 37 km NNW of this epicentre
- 5.8 The 1980 Livermore, California Earthquake · 38 km E of this epicentre
- 5.4 9 km NE of Livermore, California · 46 km ESE of this epicentre
- 5.3 The 1957 San Francisco, California Earthquake · 35 km SW 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 37.8915, -122.2010. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Contra Costa County, CA | 22 km (14 mi) | E | earthquakes near Contra Costa County |
| Alameda County, CA | 37 km (23 mi) | SE | earthquakes near Alameda County |
| Solano County, CA | 48 km (30 mi) | NNE | earthquakes near Solano County |
| Marin County, CA | 51 km (32 mi) | WNW | earthquakes near Marin County |
| San Mateo County, CA | 55 km (34 mi) | SSW | earthquakes near San Mateo County |
| Napa County, CA | 69 km (43 mi) | N | earthquakes near Napa County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
42 earthquakes have been recorded within 50 km since this one.
- 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
- 1.5 4km NW of Dublin, CA
- 1.6 1km ENE of Alameda, CA
- 2.3 12km SW of Muir Beach, CA
- 1.9 1km N of East Richmond Heights, CA
- 1.6 2km W of Concord, CA
- 1.5 0km NW of Danville, CA
- 1.6 4km NNW of Pacifica, CA
- 2.1 1km WNW of Danville, CA
- 2.8 2km N of Piedmont, CA
- 1.5 5km E of Vallejo, CA
- 1.7 7km W of Newark, 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.