Earthquake · reviewed by a seismologist
M 1.6md
Earthquake near Greenfield, CA
No earthquake was likely felt in Greenfield in the 24 hours to 4:07 pm PST (00:07 UTC). The last one was M 3.0, 38 km (23 mi) N, at 2:58 pm PDT on 22 October 2026, estimated intensity II (weak) in town. Every earthquake near Greenfield
This page: a magnitude 1.6 earthquake was recorded 8 km (5 mi) west-northwest of Greenfield, CA, at 7:33 pm PDT on 2 August 2021 (02:33 UTC), 8.4 km deep.
USGS: 8km WNW of Greenfield, CA
47 km (29 mi) SE of Salinas, CA · 115 km (71 mi) SSE of San Jose, CA
- When
- 7:33 pm PDT on 2 August 2021 ()
- Where
- 8 km (5 mi) west-northwest of Greenfield, CA · earthquakes near Greenfield
- Magnitude
- M 1.6 (md)
- Depth
- 8.4 km below the surface
- Felt
- no reports yet
- Nearest
- Monterey County, 11 km S
- Nearest mapped fault
- Monterey Bay- Tularcitos fault, 15 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 1920 days ago
Earthquake alerts for Greenfield, 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 8 km (5 mi) from the epicentre. In Greenfield, 8 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: Soledad, Gonzales, King City.
How big was it?
This earthquake released about 8.7 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.
- Mineral, Virginia 2011 M 5.8 1,700,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,200,000× the energy of this one
- Around the size people start to feel M 3.0 110× the energy of this one
- This earthquake M 1.6 about 8.7 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 4.7 on 2019-10-15 — about 40,000 times the energy of this one.
Before 2016, the USGS record lists 12 earthquakes of M5 or more within 50 km; the five largest:
- 5.9 10 km SE of Tres Pinos, California · 45 km NNE of this epicentre
- 5.8 Near Paicines, California · 38 km NNE of this epicentre
- 5.5 12 km S of Tres Pinos, California · 39 km N of this epicentre
- 5.3 24 km NE of San Lucas, California · 43 km E of this epicentre
- 5.2 5 km SSW of Spreckels, California · 40 km NW 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 36.3370, -121.3365. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Monterey County, CA | 11 km (7 mi) | S | earthquakes near Monterey County |
| San Benito County, CA | 38 km (24 mi) | NE | earthquakes near San Benito County |
| Santa Cruz County, CA | 96 km (60 mi) | NW | earthquakes near Santa Cruz County |
| Santa Clara County, CA | 103 km (64 mi) | NNW | earthquakes near Santa Clara County |
| Merced County, CA | 110 km (68 mi) | NNE | earthquakes near Merced County |
| San Luis Obispo County, CA | 132 km (82 mi) | SE | earthquakes near San Luis Obispo County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
58 earthquakes have been recorded within 50 km since this one.
- 2.0 14km SSE of Tres Pinos, CA
- 1.8 14km SSE of Tres Pinos, CA
- 1.5 4km NNW of Pinnacles, CA
- 2.0 7km NNW of Pinnacles, CA
- 2.8 6km NW of Pinnacles, CA
- 2.0 14km SSE of Tres Pinos, CA
- 1.7 10km NW of Pinnacles, CA
- 2.1 8km SSW of Tres Pinos, CA
- 1.9 6km S of Tres Pinos, CA
- 1.6 7km NW of Pinnacles, CA
- 1.9 8km NW of Pinnacles, CA
- 1.9 13km SSW of Tres Pinos, CA
- 1.5 2km NNE of Pinnacles, CA
- 1.5 7km NNW of Pinnacles, CA
- 2.0 10km SE of Pinnacles, 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.