Earthquake · reviewed by a seismologist
M 2.6ml
Earthquake near Fontana, CA
No earthquake was likely felt in Fontana in the 24 hours to 9:16 am PST (17:16 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 2.6 earthquake was recorded 8 km (5 mi) north-northwest of Fontana, CA, at 5:17 pm PDT on 4 May 2018 (00:17 UTC), 7.1 km deep. 100 people have reported feeling it to USGS.
USGS: 7km NNW of Fontana, CA
5 km (3 mi) NNW of Fontana, CA · 87 km (54 mi) E of Los Angeles, CA
- When
- 5:17 pm PDT on 4 May 2018 ()
- Where
- 8 km (5 mi) north-northwest of Fontana, CA · earthquakes near Fontana
- Magnitude
- M 2.6 (ml)
- Depth
- 7.1 km below the surface
- Felt
- 100 reports · strongest reported intensity III
- Nearest
- Orange County, 60 km SSW
- Nearest mapped fault
- Sierra Madre 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 3031 days ago
Earthquake alerts for Fontana, 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 22 km (14 mi) from the epicentre. In Fontana, 8 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: Fontana 8 km, intensity III · Rialto 11 km, intensity II · Rancho Cucamonga 12 km, intensity II · Muscoy 12 km, intensity II · Upland 17 km, intensity II · Colton 17 km, intensity II · San Bernardino 18 km, intensity II · Rubidoux 19 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 230 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.6 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 65,000× the energy of this one
- Magna, Utah 2020 M 5.7 46,000× the energy of this one
- Around the size people start to feel M 3.0 4.1× the energy of this one
- This earthquake M 2.6 about 230 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 9 earthquakes of M5 or more within 50 km; the five largest:
- 6.2 3 km SE of San Bernardino, California · 21 km ESE of this epicentre
- 5.8 The 1991 Sierra Madre, California Earthquake · 49 km WNW of this epicentre
- 5.6 7km ENE of Running Springs, CA · 41 km ENE of this epicentre
- 5.5 The 1990 Upland, California Earthquake · 20 km W of this epicentre
- 5.4 5km S of Chino Hills, CA · 35 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 34.1548, -117.4758. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Orange County, CA | 60 km (37 mi) | SSW | earthquakes near Orange County |
| Los Angeles County, CA | 72 km (45 mi) | W | earthquakes near Los Angeles County |
| San Bernardino County, CA | 142 km (88 mi) | ENE | earthquakes near San Bernardino County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
49 earthquakes have been recorded within 50 km since this one.
- 1.5 3km ESE of Home Gardens, CA
- 1.6 6km SSW of Redlands, CA
- 2.1 4km NW of Glen Avon, CA
- 2.4 6km SE of Ontario, CA
- 1.7 6km SE of Ontario, CA
- 2.1 2km SSE of Devore, CA
- 1.7 3km SE of Loma Linda, CA
- 1.6 4km SE of Home Gardens, CA
- 2.1 6km SE of Ontario, CA
- 1.6 6km SE of Ontario, CA
- 2.5 6km SE of Ontario, CA
- 3.6 6km SE of Ontario, CA
- 2.0 2km SE of Loma Linda, CA
- 1.9 9km WSW of Wrightwood, CA
- 2.6 4km SE of Loma Linda, 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.