Earthquake near Greenfield, CA

A magnitude 2.3 earthquake was recorded 27 km (16 mi) NE of Greenfield, CA, at 1:26 am PDT on 27 August 2016 (08:26 UTC). This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

Earthquakes near other towns within 30 km: Soledad, King City.

How big was it?

This earthquake released about 79 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 190,000× the energy of this one
2. Magna, Utah 2020 M 5.7 130,000× the energy of this one
3. Around the size people start to feel M 3.0 12× the energy of this one
4. This earthquake M 2.3 about 79 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 4.2 on 2016-07-19 — about 810 times the energy of this one.

Before 2016, the USGS record lists 13 earthquakes of M5 or more within 50 km; the five largest:

1. 6.1 Northwest of Huron, California · 37 km E of this epicentre May 26, 1905
2. 5.9 10 km SE of Tres Pinos, California · 35 km NNW of this epicentre Apr 9, 1961
3. 5.8 Near Paicines, California · 32 km NW of this epicentre Aug 6, 1916
4. 5.8 29 km NE of San Lucas, California · 28 km SE of this epicentre Jul 25, 1926
5. 5.5 12 km S of Tres Pinos, California · 36 km NW of this epicentre Apr 9, 1961

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 36.4637, -121.0068. Map © OpenStreetMap contributors.

Nearby places

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.

1. 2.7 17 km SSE of Tres Pinos, California 08:32 UTC
2. 2.0 23 km NE of San Ardo, California 13:39 UTC
3. 2.0 23 km NE of San Ardo, California 01:24 UTC
4. 1.9 22 km NE of Soledad, California 17:14 UTC
5. 1.6 22 km NE of San Lucas, California 18:32 UTC
6. 2.1 10 km S of Tres Pinos, California 23:47 UTC
7. 1.8 21 km NE of Soledad, California 14:47 UTC
8. 1.9 24 km ENE of Soledad, California 15:52 UTC
9. 1.8 22 km SSW of South Dos Palos, California 03:23 UTC
10. 2.1 9 km SSW of Tres Pinos, California 21:45 UTC
11. 2.8 17 km SSE of Tres Pinos, California 09:18 UTC
12. 2.0 20 km SSE of Tres Pinos, California 13:21 UTC
13. 1.6 20 km SSE of Tres Pinos, California 10:34 UTC
14. 2.1 23 km NE of Soledad, California 04:24 UTC
15. 1.6 23 km NE of Soledad, California 19:47 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 04:07 UTC. 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.