QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6md

Earthquake near Greenfield, CA

No earthquake was likely felt in Greenfield in the 24 hours to 3:27 am PST (11:27 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 25 km (15 mi) east-northeast of Greenfield, CA, at 5:09 am PST on 21 November 2019 (13:09 UTC), 6.8 km deep.

USGS: 19km SE of Pinnacles, CA

5:09 am PST, Nov 21, 2019 · · 6.8 km deep · released about 8.7 lb of TNT

10 km30 km60 km120 km N San Benito County 24 kmMonterey County 35 kmMerced County 91 kmSanta Clara County 110 kmKings County 112 kmSanta Cruz County 113 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
5:09 am PST on 21 November 2019 ()
Where
25 km (15 mi) east-northeast of Greenfield, CA · earthquakes near Greenfield
Magnitude
M 1.6 (md)
Depth
6.8 km below the surface
Felt
no reports yet
Nearest
San Benito County, 24 km NNW
Nearest mapped fault
San Andreas fault, under 1 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 2536 days ago

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 Greenfield, 25 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: 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.

  1. Mineral, Virginia 2011 M 5.8 1,700,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,200,000× the energy of this one
  3. Around the size people start to feel M 3.0 110× the energy of this one
  4. 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:

  1. 6.1 Northwest of Huron, California · 36 km ENE of this epicentre
  2. 5.9 10 km SE of Tres Pinos, California · 41 km NNW of this epicentre
  3. 5.8 Near Paicines, California · 37 km NW of this epicentre
  4. 5.8 29 km NE of San Lucas, California · 23 km ESE of this epicentre
  5. 5.5 12 km S of Tres Pinos, California · 41 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 36.4090, -120.9902. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
San Benito County, CA 24 km (15 mi) NNW earthquakes near San Benito County
Monterey County, CA 35 km (22 mi) WSW earthquakes near Monterey County
Merced County, CA 91 km (56 mi) NNE earthquakes near Merced County
Santa Clara County, CA 110 km (68 mi) NW earthquakes near Santa Clara County
Kings County, CA 112 km (69 mi) ESE earthquakes near Kings County
Santa Cruz County, CA 113 km (70 mi) NW earthquakes near Santa Cruz County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

50 earthquakes have been recorded within 50 km since this one.

  1. 1.6 8km NW of Pinnacles, CA
  2. 3.3 22km NE of San Lucas, CA
  3. 2.2 12km S of Tres Pinos, CA
  4. 2.3 12km S of Tres Pinos, CA
  5. 2.5 4km ESE of Pinnacles, CA
  6. 1.9 6km ESE of Pinnacles, CA
  7. 1.5 7km ENE of Pinnacles, CA
  8. 2.4 13km SE of Pinnacles, CA
  9. 1.8 17km E of Pinnacles, CA
  10. 1.8 13km SE of Pinnacles, CA
  11. 2.6 16km SSE of Tres Pinos, CA
  12. 1.8 7km NNW of Pinnacles, CA
  13. 1.7 11km SSW of San Lucas, CA
  14. 2.5 7km E of Pinnacles, CA
  15. 2.2 13km NW 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

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.