Earthquake · reviewed by a seismologist
M 4.2mw
Earthquake near Fontana, CA
No earthquake was likely felt in Fontana in the 24 hours to 4:28 am PST (12:28 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 4.2 earthquake was recorded 20 km (12 mi) north-northwest of Fontana, CA, at 10:55 am PST on 5 January 2024 (18:55 UTC), 9.1 km deep. 12,827 people have reported feeling it to USGS.
USGS: 1 km W of Lytle Creek, CA
87 km (54 mi) ENE of Los Angeles, CA · 15 km (9 mi) NNE of Rancho Cucamonga, CA
- When
- 10:55 am PST on 5 January 2024 ()
- Where
- 20 km (12 mi) north-northwest of Fontana, CA · earthquakes near Fontana
- Magnitude
- M 4.2 (mw)
- Depth
- 9.1 km below the surface
- Felt
- 12,827 reports · strongest reported intensity V
- Measured shaking
- intensity V (ShakeMap)
- USGS impact alert
- green
- Nearest
- Orange County, 69 km SSW
- Nearest mapped fault
- San Jacinto fault, 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 326 days ago
Earthquake alerts for Fontana, CA
Get a notification in this browser when USGS records an earthquake near Fontana, CA. No account or email needed.
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 light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.
At this magnitude and depth, people at rest would likely notice it out to about 108 km (67 mi) from the epicentre. In Fontana, 20 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: Wrightwood 16 km, intensity III · Rancho Cucamonga 19 km, intensity III · Muscoy 19 km, intensity III · Phelan 20 km, intensity III · Fontana 20 km, intensity III · Rialto 21 km, intensity III · Upland 22 km, intensity III · Ontario 25 km, intensity III. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 25 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.2 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 6,700× the energy of this one
- Mineral, Virginia 2011 M 5.8 300× the energy of this one
- Magna, Utah 2020 M 5.7 210× the energy of this one
- This earthquake M 4.2 about 25 tons of TNT
- Around the size people start to feel M 3.0 this one released 53× 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 2.2 times the energy of this one.
Before 2016, the USGS record lists 8 earthquakes of M5 or more within 50 km; the five largest:
- 6.2 3 km SE of San Bernardino, California · 30 km SE of this epicentre
- 5.8 The 1991 Sierra Madre, California Earthquake · 45 km W of this epicentre
- 5.6 7km ENE of Running Springs, CA · 43 km E of this epicentre
- 5.5 The 1990 Upland, California Earthquake · 21 km SW of this epicentre
- 5.4 5km S of Chino Hills, CA · 42 km SW 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 34.2583, -117.5088. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Orange County, CA | 69 km (43 mi) | SSW | earthquakes near Orange County |
| Los Angeles County, CA | 70 km (43 mi) | W | earthquakes near Los Angeles County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
45 earthquakes have been recorded within 50 km since this one.
- 3.1 3 km SW of San Bernardino, CA
- 1.5 2 km SE of Loma Linda, CA
- 1.6 5 km ESE of Yorba Linda, CA
- 1.6 4 km SE of Home Gardens, CA
- 2.3 8 km SSE of Wrightwood, CA
- 1.5 6 km SSW of Devore, CA
- 1.6 1 km S of Colton, CA
- 1.5 9 km W of Calimesa, CA
- 1.9 9 km W of Calimesa, CA
- 1.6 6 km N of Moreno Valley, CA
- 1.6 5 km SSE of Home Gardens, CA
- 2.4 2 km SSE of Loma Linda, CA
- 1.5 4 km SE of Loma Linda, CA
- 1.5 6 km S of Lytle Creek, CA
- 2.0 6 km ENE of Running Springs, 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.