Earthquake · reviewed by a seismologist
M 3.2ml
Earthquake near Brea, CA
No earthquake was likely felt in Brea in the 24 hours to 7:49 am PST (15:49 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 3.2 earthquake was recorded 2 km (2 mi) east-northeast of Brea, CA, at 9:23 am PST on 28 December 2019 (17:23 UTC), 8.7 km deep. 733 people have reported feeling it to USGS.
USGS: 2km ENE of Brea, CA
5 km (3 mi) NNW of Placentia, CA · 50 km (31 mi) ESE of Los Angeles, CA
- When
- 9:23 am PST on 28 December 2019 ()
- Where
- 2 km (2 mi) east-northeast of Brea, CA · earthquakes near Brea
- Magnitude
- M 3.2 (ml)
- Depth
- 8.7 km below the surface
- Felt
- 733 reports · strongest reported intensity IV
- Measured shaking
- intensity IV (ShakeMap)
- 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 2047 days ago
Earthquake alerts for Brea, CA
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Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
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 46 km (29 mi) from the epicentre. In Brea, 2 km away, the estimate is intensity III (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: Brea 2 km, intensity III · Placentia 6 km, intensity III · Rowland Heights 6 km, intensity III · La Habra 6 km, intensity III · Yorba Linda 7 km, intensity III · Fullerton 8 km, intensity III · Walnut 10 km, intensity III · Anaheim 11 km, intensity III. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 1,900 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.2 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 180,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 7,900× the energy of this one
- Magna, Utah 2020 M 5.7 5,600× the energy of this one
- This earthquake M 3.2 about 1,900 lb of TNT
- Around the size people start to feel M 3.0 this one released 2× more
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 59 times the energy of this one.
Before 2016, the USGS record lists 14 earthquakes of M5 or more within 50 km; the five largest:
- 6.4 The 1933 Long Beach, California Earthquake · 35 km SSW of this epicentre
- 5.9 The 1987 Whittier Narrows, California Earthquake · 24 km NW of this epicentre
- 5.8 The 1991 Sierra Madre, California Earthquake · 40 km NNW of this epicentre
- 5.5 The 1990 Upland, California Earthquake · 29 km NE of this epicentre
- 5.4 5km S of Chino Hills, CA · 10 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 33.9267, -117.8765. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction 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 | 125 km (78 mi) | WNW | earthquakes near Ventura County |
| San Diego County, CA | 143 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
53 earthquakes have been recorded within 50 km since this one.
- 1.6 0km S of View Park-Windsor Hills, CA
- 1.6 1km SE of View Park-Windsor Hills, CA
- 1.6 0km SE of View Park-Windsor Hills, CA
- 3.7 1km S of View Park-Windsor Hills, CA
- 2.1 1km S of View Park-Windsor Hills, CA
- 1.6 2km NNE of Laguna Niguel, CA
- 1.7 4km E of Rancho Cucamonga, CA
- 1.9 3km NNW of Walnut, CA
- 1.7 5km SSE of Home Gardens, CA
- 1.5 2km SSE of View Park-Windsor Hills, CA
- 1.6 8km WNW of Lytle Creek, CA
- 1.6 3km SSW of Willowbrook, CA
- 1.6 7km NW of Glen Avon, CA
- 1.8 6km E of Ontario, CA
- 1.7 2km ENE of Villa Park, 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
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.