QuakeIndex

Earthquake · reviewed by a seismologist

M 2.4ml

Earthquake near Brea, CA

No earthquake was likely felt in Brea in the 24 hours to 3:27 am PST (11:27 UTC). The last one was M 3.2, 30 km (19 mi) WSW, at 12:44 am PDT on 9 October 2026, estimated intensity II (weak) in town; 1,090 felt reports to USGS. Every earthquake near Brea

This page: a magnitude 2.4 earthquake was recorded in Brea, CA, at 2:36 pm PST on 21 December 2016 (22:36 UTC), 3.2 km deep. 18 people have reported feeling it to USGS.

USGS: 1km ENE of Brea, CA

5 km (3 mi) NE of Fullerton, CA · 49 km (31 mi) ESE of Los Angeles, CA

2:36 pm PST, Dec 21, 2016 · · 3.2 km deep · released about 110 lb of TNT

Every earthquake near Brea Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Orange County 29 kmLos Angeles County 46 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
2:36 pm PST on 21 December 2016 ()
Where
in Brea, CA · earthquakes near Brea
Magnitude
M 2.4 (ml)
Depth
3.2 km below the surface
Felt
18 reports · strongest reported intensity V
Nearest
Orange County, 29 km SSE
Nearest mapped fault
Puente Hills blind thrust system, 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 1558 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 21 km (13 mi) from the epicentre. 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: Brea in town, intensity III · La Habra 5 km, intensity III · Placentia 6 km, intensity III · Rowland Heights 6 km, intensity III · Fullerton 7 km, intensity III · Yorba Linda 8 km, intensity III · Anaheim 10 km, intensity II · Hacienda Heights 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 110 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.4 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 130,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 95,000× the energy of this one
  3. Around the size people start to feel M 3.0 8.5× the energy of this one
  4. This earthquake M 2.4 about 110 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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

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

  1. 6.4 The 1933 Long Beach, California Earthquake · 34 km SSW of this epicentre
  2. 5.9 The 1987 Whittier Narrows, California Earthquake · 23 km NW of this epicentre
  3. 5.8 The 1991 Sierra Madre, California Earthquake · 40 km NNW of this epicentre
  4. 5.5 The 1990 Upland, California Earthquake · 30 km NE of this epicentre
  5. 5.4 5km S of Chino Hills, CA · 12 km ENE 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 33.9205, -117.8887. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Orange County, CA 29 km (18 mi) SSE earthquakes near Orange County
Los Angeles County, CA 46 km (29 mi) NW earthquakes near Los Angeles County
Ventura County, CA 124 km (77 mi) WNW earthquakes near Ventura County
San Diego County, CA 144 km (89 mi) SE earthquakes near San Diego County

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

Aftershocks so far

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

  1. 1.7 2 km N of East La Mirada, California
  2. 1.9 2 km N of East La Mirada, California
  3. 1.6 3 km SE of Sunset Beach, California
  4. 1.9 2km SW of MacArthur Park, CA
  5. 1.6 7km SSE of Home Gardens, CA
  6. 2.1 2km SE of Brea, CA
  7. 1.5 3km NE of Fontana, CA
  8. 1.6 3km E of Marina del Rey, CA
  9. 1.7 10km WNW of Corona, CA
  10. 2.1 4km SW of Baldwin Hills, CA
  11. 1.6 2km WSW of Lakewood, CA
  12. 1.6 2km SE of Hawthorne, CA
  13. 1.6 4km SE of Home Gardens, CA
  14. 1.8 8km N of Rancho Cucamonga, CA
  15. 1.9 2km NW of Willowbrook, 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.