QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1ml

Earthquake near Fontana, CA

No earthquake was likely felt in Fontana in the 24 hours to 6:10 am PST (14:10 UTC). The last one was M 1.6, 5 km (3 mi) W, at 6:17 am PDT on 26 October 2026, estimated intensity II (weak) in town. Every earthquake near Fontana

This page: a magnitude 2.1 earthquake was recorded 12 km (8 mi) north-northeast of Fontana, CA, at 2:52 am PST on 4 February 2022 (10:52 UTC), 13 km deep.

USGS: 2km S of Devore, CA

9 km (6 mi) N of Rialto, CA · 95 km (59 mi) ENE of Los Angeles, CA

2:52 am PST, Feb 4, 2022 · · 13 km deep · released about 51 lb of TNT

10 km30 km60 km120 km N Orange County 68 kmLos Angeles County 79 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
2:52 am PST on 4 February 2022 ()
Where
12 km (8 mi) north-northeast of Fontana, CA · earthquakes near Fontana
Magnitude
M 2.1 (ml)
Depth
13 km below the surface
Felt
no reports yet
Nearest
Orange County, 68 km SSW
Nearest mapped fault
San Jacinto fault, 3 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 1742 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 Fontana, 12 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: Muscoy 7 km, intensity II · Rialto 11 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 51 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 300,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 210,000× the energy of this one
  3. Around the size people start to feel M 3.0 19× the energy of this one
  4. This earthquake M 2.1 about 51 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 4.4 on 2018-08-29 — about 2,200 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. 6.2 3 km SE of San Bernardino, California · 18 km SE of this epicentre
  2. 5.6 7km ENE of Running Springs, CA · 33 km E of this epicentre
  3. 5.5 The 1990 Upland, California Earthquake · 28 km WSW of this epicentre
  4. 5.4 5km S of Chino Hills, CA · 44 km SW of this epicentre
  5. 5.3 Near San Bernardino, California · 28 km E 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 34.2007, -117.3997. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Orange County, CA 68 km (42 mi) SSW earthquakes near Orange County
Los Angeles County, CA 79 km (49 mi) W earthquakes near Los Angeles County
San Bernardino County, CA 133 km (83 mi) ENE earthquakes near San Bernardino County

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

Aftershocks so far

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

  1. 1.9 8km WSW of Corona, CA
  2. 2.4 8km WSW of Corona, CA
  3. 1.8 8km W of Big Bear Lake, CA
  4. 1.7 6km ESE of Yucaipa, CA
  5. 1.8 4km SE of Home Gardens, CA
  6. 1.7 7km SE of Loma Linda, CA
  7. 1.6 4km W of Calimesa, CA
  8. 1.6 4km NNW of Lytle Creek, CA
  9. 1.6 7km S of Redlands, CA
  10. 1.5 5km SSE of Home Gardens, CA
  11. 1.7 11km NE of Yucaipa, CA
  12. 2.2 8km SSW of Calimesa, CA
  13. 1.6 11km NW of Big Bear Lake, CA
  14. 1.8 2km NW of Loma Linda, CA
  15. 1.9 3km NE of Yorba Linda, 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.