Earthquake · reviewed by a seismologist
M 1.5md
Earthquake near Benicia, CA
No earthquake was likely felt in Benicia in the 24 hours to 11:03 pm PST (07:03 UTC). The last one was M 1.8, 10 km (6 mi) N, at 11:09 am PST on 4 November 2026, estimated intensity II (weak) in town. Every earthquake near Benicia
This page: a magnitude 1.5 earthquake was recorded 3 km (2 mi) north-northwest of Benicia, CA, at 4:30 am PST on 11 November 2020 (12:30 UTC), 4.9 km deep. 3 people have reported feeling it to USGS.
USGS: 3km NNW of Benicia, CA
9 km (6 mi) ESE of Vallejo, CA · 39 km (24 mi) NNE of San Francisco, CA
- When
- 4:30 am PST on 11 November 2020 ()
- Where
- 3 km (2 mi) north-northwest of Benicia, CA · earthquakes near Benicia
- Magnitude
- M 1.5 (md)
- Depth
- 4.9 km below the surface
- Felt
- 3 reports · strongest reported intensity III
- Nearest
- Contra Costa County, 26 km SE
- Nearest mapped fault
- Green Valley fault, 8 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 1556 days ago
Earthquake alerts for Benicia, 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 9 km (6 mi) from the epicentre. In Benicia, 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: Benicia 3 km, intensity II · Crockett 4 km, intensity II · Martinez 7 km, intensity II · Vallejo 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 5.7 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 2,600,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,900,000× the energy of this one
- Around the size people start to feel M 3.0 170× the energy of this one
- This earthquake M 1.5 about 5.7 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 26,000 times the energy of this one.
Before 2016, the USGS record lists 5 earthquakes of M5 or more within 50 km:
- 7.9 The 1906 San Francisco, California Earthquake · 49 km SW of this epicentre
- 6.0 The 2014 South Napa, California Earthquake · 20 km NW of this epicentre
- 5.8 The 1980 Livermore, California Earthquake · 44 km SE of this epicentre
- 5.4 South of Elmira, California · 35 km NE of this epicentre
- 5.1 11 km E of Blackhawk, California · 45 km SE 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 38.0718, -122.1708. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Contra Costa County, CA | 26 km (16 mi) | SE | earthquakes near Contra Costa County |
| Solano County, CA | 30 km (18 mi) | NE | earthquakes near Solano County |
| Napa County, CA | 50 km (31 mi) | NNW | earthquakes near Napa County |
| Marin County, CA | 50 km (31 mi) | W | earthquakes near Marin County |
| Alameda County, CA | 52 km (33 mi) | SSE | earthquakes near Alameda County |
| Yolo County, CA | 72 km (44 mi) | NNE | earthquakes near Yolo County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
49 earthquakes have been recorded within 50 km since this one.
- 1.6 2km N of San Ramon, CA
- 2.3 2km SE of Danville, CA
- 1.8 2km ESE of Berkeley, CA
- 2.2 3km SW of Green Valley, CA
- 2.0 0km SE of Pleasant Hill, CA
- 1.5 3km ESE of Berkeley, CA
- 2.6 3km ESE of Berkeley, CA
- 2.1 2km WNW of Castro Valley, CA
- 1.9 2km NW of Orinda, CA
- 1.7 9km NW of San Francisco Zoo, CA
- 2.0 5km SW of Danville, CA
- 3.0 1km W of Concord, CA
- 2.0 6km WNW of San Francisco Zoo, CA
- 1.6 3km ENE of Walnut Creek, CA
- 1.8 7km NW of San Francisco Zoo, 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.