QuakeIndex

Earthquake · reviewed by a seismologist

M 2.8md

Earthquake near Coalinga, CA

No earthquake was likely felt in Coalinga in the 24 hours to 4:20 am PST (12:20 UTC). The last one was M 2.3, 4 km (3 mi) SE, at 1:44 am PDT on 4 October 2026, estimated intensity II (weak) in town. Every earthquake near Coalinga

This page: a magnitude 2.8 earthquake was recorded 25 km (16 mi) west-southwest of Coalinga, CA, at 7:45 pm PDT on 15 September 2021 (02:45 UTC), 4.4 km deep. 2 people have reported feeling it to USGS.

USGS: 23km NW of Parkfield, CA

7:45 pm PDT, Sep 15, 2021 · · 4.4 km deep · released about 460 lb of TNT

10 km30 km60 km120 km N Monterey County 67 kmKings County 72 kmSan Luis Obispo County 74 kmSan Benito County 76 kmFresno County 117 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
7:45 pm PDT on 15 September 2021 ()
Where
25 km (16 mi) west-southwest of Coalinga, CA · earthquakes near Coalinga
Magnitude
M 2.8 (md)
Depth
4.4 km below the surface
Felt
2 reports · strongest reported intensity II
Nearest
Monterey County, 67 km WNW
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 1557 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 26 km (16 mi) from the epicentre. In Coalinga, 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.

Likely felt in: Coalinga 25 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 460 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 33,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 23,000× the energy of this one
  3. Around the size people start to feel M 3.0 2.1× the energy of this one
  4. This earthquake M 2.8 about 460 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 4.3 on 2019-12-17 — about 180 times the energy of this one.

Before 2016, the USGS record lists 24 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.7 The 1983 Coalinga, California Earthquake · 34 km NE of this epicentre
  2. 6.5 1922 Parkfield, California Earthquake · 46 km SE of this epicentre
  3. 6.4 1901 Parkfield, California Earthquake · 11 km ESE of this epicentre
  4. 6.0 2004 Parkfield, California Earthquake · 34 km SE of this epicentre
  5. 5.8 29 km NE of San Lucas, California · 32 km NNW 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 36.0445, -120.6135. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Monterey County, CA 67 km (41 mi) WNW earthquakes near Monterey County
Kings County, CA 72 km (45 mi) E earthquakes near Kings County
San Luis Obispo County, CA 74 km (46 mi) SSE earthquakes near San Luis Obispo County
San Benito County, CA 76 km (47 mi) NNW earthquakes near San Benito County
Fresno County, CA 117 km (73 mi) NE earthquakes near Fresno County

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

Aftershocks so far

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

  1. 2.1 22km ENE of San Lucas, CA
  2. 3.3 1km W of Parkfield, CA
  3. 2.2 17km ENE of New Idria, CA
  4. 2.5 11km N of Avenal, CA
  5. 1.6 12km NW of Parkfield, CA
  6. 2.1 14km N of Coalinga, CA
  7. 2.2 4km WSW of Paso Robles, CA
  8. 1.7 12km SSW of San Lucas, CA
  9. 1.7 14km SSW of Avenal, CA
  10. 1.9 14km SSW of Avenal, CA
  11. 1.9 24km NE of King City, CA
  12. 1.8 24km NW of Parkfield, CA
  13. 1.5 12km NW of Parkfield, CA
  14. 1.8 10km WNW of New Idria, CA
  15. 1.6 23km ENE of San Ardo, 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.