Earthquake · reviewed by a seismologist
M 3.3ml
Earthquake near Fullerton, CA
No earthquake was likely felt in Fullerton in the 24 hours to 3:20 am PST (11:20 UTC). The last one was M 3.2, 26 km (16 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 Fullerton
This page: a magnitude 3.3 earthquake was recorded in Fullerton, CA, at 8:09 pm PST on 4 December 2023 (04:09 UTC), 9.8 km deep. 4,309 people have reported feeling it to USGS.
USGS: 2 km E of Fullerton, CA
in Fullerton, CA · 49 km (30 mi) ESE of Los Angeles, CA
- When
- 8:09 pm PST on 4 December 2023 ()
- Where
- in Fullerton, CA · earthquakes near Fullerton
- Magnitude
- M 3.3 (ml)
- Depth
- 9.8 km below the surface
- Felt
- 4,309 reports · strongest reported intensity IV
- Measured shaking
- intensity IV (ShakeMap)
- Nearest
- Orange County, 26 km SSE
- Nearest mapped fault
- Puente Hills blind thrust system, under 1 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 100 days ago
Earthquake alerts for Fullerton, 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 53 km (33 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: Fullerton in town, intensity III · Placentia 4 km, intensity III · Brea 4 km, intensity III · Anaheim 5 km, intensity III · La Habra 7 km, intensity III · Buena Park 8 km, intensity III · Yorba Linda 9 km, intensity III · La Mirada 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 1.5 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.3 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 110,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 5,100× the energy of this one
- Magna, Utah 2020 M 5.7 3,600× the energy of this one
- This earthquake M 3.3 about 1.5 tons of TNT
- Around the size people start to feel M 3.0 this one released 3.1× 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 4.5 on 2020-09-19 — about 65 times the energy of this one.
Before 2016, the USGS record lists 13 earthquakes of M5 or more within 50 km; the five largest:
- 6.4 The 1933 Long Beach, California Earthquake · 29 km SSW of this epicentre
- 5.9 The 1987 Whittier Narrows, California Earthquake · 26 km NW of this epicentre
- 5.8 The 1991 Sierra Madre, California Earthquake · 44 km N of this epicentre
- 5.5 The 1990 Upland, California Earthquake · 35 km NNE of this epicentre
- 5.4 5km S of Chino Hills, CA · 15 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 33.8783, -117.9080. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Orange County, CA | 26 km (16 mi) | SSE | earthquakes near Orange County |
| Los Angeles County, CA | 48 km (30 mi) | NW | earthquakes near Los Angeles County |
| Ventura County, CA | 125 km (78 mi) | WNW | earthquakes near Ventura County |
| San Diego County, CA | 142 km (88 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
46 earthquakes have been recorded within 50 km since this one.
- 1.6 5 km SSE of Home Gardens, CA
- 1.6 3 km ENE of View Park-Windsor Hills, CA
- 1.9 4 km ESE of Placentia, CA
- 1.6 2 km NE of Yorba Linda, CA
- 2.0 3 km SE of Ontario, CA
- 1.5 9 km N of Rancho Cucamonga, CA
- 1.9 10 km ENE of Villa Park, CA
- 1.7 4 km SE of Home Gardens, CA
- 1.9 2 km ENE of El Segundo, CA
- 2.2 2 km N of Huntington Park, CA
- 2.5 3 km N of Huntington Park, CA
- 1.7 4 km N of Laguna Beach, CA
- 2.0 3 km SE of Marina del Rey, CA
- 3.6 3 km ESE of Ontario, CA
- 1.8 6 km NW of Glen Avon, 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.