QuakeIndex

Earthquake · reviewed by a seismologist

M 2.2ml

Earthquake near Bradbury, CA

No earthquake was likely felt in Bradbury in the 24 hours to 4:14 am PST (12:14 UTC). The last one was M 3.8, 78 km (48 mi) WNW, at 8:00 pm PDT on 29 September 2026, estimated intensity II (weak) in town; 199 felt reports to USGS. Every earthquake near Bradbury

This page: a magnitude 2.2 earthquake was recorded 10 km (6 mi) north-northeast of Bradbury, CA, at 4:46 pm PST on 3 December 2021 (00:46 UTC), 6.7 km deep. 1 person has reported feeling it to USGS.

USGS: 10km NNE of Bradbury, CA

12 km (8 mi) NW of Glendora, CA · 50 km (31 mi) ENE of Los Angeles, CA

4:46 pm PST, Dec 3, 2021 · · 6.7 km deep · released about 58 lb of TNT

Every earthquake near Bradbury Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Los Angeles County 30 kmOrange County 63 kmVentura County 111 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
4:46 pm PST on 3 December 2021 ()
Where
10 km (6 mi) north-northeast of Bradbury, CA · earthquakes near Bradbury
Magnitude
M 2.2 (ml)
Depth
6.7 km below the surface
Felt
1 report · strongest reported intensity II
Nearest
Los Angeles County, 30 km W
Nearest mapped fault
Sierra Madre fault, 2 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 1805 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 17 km (11 mi) from the epicentre. In Bradbury, 10 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: Monrovia 11 km, intensity II · Azusa 11 km, intensity II · Glendora 12 km, intensity II · Sierra Madre 13 km, intensity II · Arcadia 13 km, intensity II · Covina 16 km, intensity II · Baldwin Park 16 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 58 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.2 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 260,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 180,000× the energy of this one
  3. Around the size people start to feel M 3.0 16× the energy of this one
  4. This earthquake M 2.2 about 58 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 4.5 on 2020-09-19 — about 3,300 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. 6.6 1971 San Fernando Earthquake, California · 45 km WNW of this epicentre
  2. 5.9 The 1987 Whittier Narrows, California Earthquake · 23 km SW of this epicentre
  3. 5.8 10km SSW of Agua Dulce, CA · 45 km WNW of this epicentre
  4. 5.8 10km SSW of Agua Dulce, CA · 45 km WNW of this epicentre
  5. 5.8 The 1991 Sierra Madre, California Earthquake · 7 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 34.2278, -117.9345. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Los Angeles County, CA 30 km (19 mi) W earthquakes near Los Angeles County
Orange County, CA 63 km (39 mi) SSE earthquakes near Orange County
Ventura County, CA 111 km (69 mi) W earthquakes near Ventura County

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

Aftershocks so far

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

  1. 2.2 7km SSW of Littlerock, CA
  2. 1.6 7km SSE of Littlerock, CA
  3. 1.8 8km N of Glendora, CA
  4. 2.1 3km NE of Gardena, CA
  5. 1.6 2km NNW of Fontana, CA
  6. 1.7 6km WNW of Fontana, CA
  7. 2.6 2km WSW of Silver Lake, CA
  8. 1.5 0km SSW of View Park-Windsor Hills, CA
  9. 1.7 4km NNW of Fontana, CA
  10. 2.1 2km S of Devore, CA
  11. 1.9 2km S of Devore, CA
  12. 2.6 4km NNW of Fontana, CA
  13. 2.0 4km NW of Fontana, CA
  14. 2.1 1km WSW of View Park-Windsor Hills, CA
  15. 3.3 1km SE of South Gate, 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.