QuakeIndex

Earthquake · reviewed by a seismologist

M 1.9md

Earthquake near Mendota, CA

No earthquake was likely felt in Mendota in the 24 hours to 4:21 am PST (12:21 UTC). The last one was M 3.9, 74 km (46 mi) WSW, at 3:19 am PDT on 11 August 2026, estimated intensity II (weak) in town; 34 felt reports to USGS. Every earthquake near Mendota

This page: a magnitude 1.9 earthquake was recorded 37 km (23 mi) southwest of Mendota, CA, at 2:38 pm PDT on 1 October 2021 (21:38 UTC), 9.1 km deep.

USGS: 9km NNE of New Idria, CA

2:38 pm PDT, Oct 1, 2021 · · 9.1 km deep · released about 24 lb of TNT

10 km30 km60 km120 km N San Benito County 43 kmMonterey County 67 kmMerced County 79 kmKings County 87 kmFresno County 92 kmMadera County 112 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
2:38 pm PDT on 1 October 2021 ()
Where
37 km (23 mi) southwest of Mendota, CA · earthquakes near Mendota
Magnitude
M 1.9 (md)
Depth
9.1 km below the surface
Felt
no reports yet
Nearest
San Benito County, 43 km WNW
Nearest mapped fault
Great Valley thrust fault system, 11 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 1867 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 12 km (7 mi) from the epicentre. In Mendota, 37 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.

How big was it?

This earthquake released about 24 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.

  1. Mineral, Virginia 2011 M 5.8 640,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 450,000× the energy of this one
  3. Around the size people start to feel M 3.0 40× the energy of this one
  4. This earthquake M 1.9 about 24 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 4.0 on 2021-08-31 — about 1,500 times the energy of this one.

Before 2016, the USGS record lists 14 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.7 The 1983 Coalinga, California Earthquake · 41 km SE of this epicentre
  2. 6.1 Northwest of Huron, California · 3 km ENE of this epicentre
  3. 5.8 29 km NE of San Lucas, California · 24 km SSW of this epicentre
  4. 5.5 11 km NNE of Coalinga, California · 42 km SE of this epicentre
  5. 5.5 11 km NE of Coalinga, California · 44 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 36.4910, -120.6342. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
San Benito County, CA 43 km (26 mi) WNW earthquakes near San Benito County
Monterey County, CA 67 km (42 mi) WSW earthquakes near Monterey County
Merced County, CA 79 km (49 mi) N earthquakes near Merced County
Kings County, CA 87 km (54 mi) ESE earthquakes near Kings County
Fresno County, CA 92 km (57 mi) ENE earthquakes near Fresno County
Madera County, CA 112 km (70 mi) NE earthquakes near Madera County

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

Aftershocks so far

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

  1. 1.9 3km NNW of Pinnacles, CA
  2. 2.1 14km N of Coalinga, CA
  3. 2.4 2km E of Pinnacles, CA
  4. 1.6 2km E of Pinnacles, CA
  5. 1.7 6km NW of Pinnacles, CA
  6. 2.7 10km NNE of New Idria, CA
  7. 1.9 24km NE of King City, CA
  8. 1.9 12km NE of Pinnacles, CA
  9. 1.6 5km ESE of Pinnacles, CA
  10. 1.8 24km NW of Parkfield, CA
  11. 1.9 4km N of Pinnacles, CA
  12. 1.7 3km N of Pinnacles, CA
  13. 1.8 10km WNW of New Idria, CA
  14. 1.7 3km N of Pinnacles, 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.