Earthquake · reviewed by a seismologist
M 1.9md
Earthquake near Crockett, CA
No earthquake was likely felt in Crockett in the 24 hours to 10:22 pm PST (06:22 UTC). The last one was M 1.8, 10 km (6 mi) NNE, at 11:09 am PST on 4 November 2026, estimated intensity II (weak) in town. Every earthquake near Crockett
This page: a magnitude 1.9 earthquake was recorded 4 km (3 mi) north-northeast of Crockett, CA, at 3:17 pm PDT on 20 April 2020 (22:17 UTC), 7.8 km deep. 3 people have reported feeling it to USGS.
USGS: 4km NNE of Crockett, CA
7 km (4 mi) ESE of Vallejo, CA · 40 km (25 mi) NNE of San Francisco, CA
- When
- 3:17 pm PDT on 20 April 2020 ()
- Where
- 4 km (3 mi) north-northeast of Crockett, CA · earthquakes near Crockett
- Magnitude
- M 1.9 (md)
- Depth
- 7.8 km below the surface
- Felt
- 3 reports · strongest reported intensity III
- Nearest
- Contra Costa County, 28 km SE
- Nearest mapped fault
- Green Valley fault, 7 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 2259 days ago
Earthquake alerts for Crockett, 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 13 km (8 mi) from the epicentre. In Crockett, 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: Crockett 4 km, intensity II · Benicia 5 km, intensity II · Vallejo 6 km, intensity II · Martinez 9 km, intensity II · Hercules 12 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 23 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 5.8 660,000× the energy of this one
- Magna, Utah 2020 M 5.7 470,000× the energy of this one
- Around the size people start to feel M 3.0 42× the energy of this one
- This earthquake M 1.9 about 23 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 6,500 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 · 18 km NW of this epicentre
- 5.8 The 1980 Livermore, California Earthquake · 46 km SE of this epicentre
- 5.4 South of Elmira, California · 34 km NE of this epicentre
- 5.1 11 km E of Blackhawk, California · 47 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 38.0868, -122.1865. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Contra Costa County, CA | 28 km (17 mi) | SE | earthquakes near Contra Costa County |
| Solano County, CA | 29 km (18 mi) | NE | earthquakes near Solano County |
| Napa County, CA | 48 km (30 mi) | NNW | earthquakes near Napa County |
| Marin County, CA | 49 km (31 mi) | W | earthquakes near Marin County |
| Alameda County, CA | 54 km (34 mi) | SSE | earthquakes near Alameda County |
| Yolo County, CA | 70 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
47 earthquakes have been recorded within 50 km since this one.
- 2.7 2km SSE of Crockett, CA
- 2.3 2km NE of El Cerrito, CA
- 1.6 15km ENE of Yountville, CA
- 1.9 13km ENE of Yountville, CA
- 2.6 6km SW of Clayton, CA
- 2.5 6km NE of Alamo, CA
- 1.6 5km E of Vallejo, CA
- 2.5 6km W of Yountville, CA
- 1.9 6km NE of Alamo, CA
- 2.5 11km SSW of Brentwood, CA
- 2.0 3km SW of American Canyon, CA
- 2.3 9km NE of Blackhawk, CA
- 1.5 12km E of Yountville, CA
- 1.8 1km WNW of Kensington, CA
- 1.8 7km N of Orinda, 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.