Earthquake · reviewed by a seismologist
M 1.7ml
Earthquake near Fontana, CA
No earthquake was likely felt in Fontana in the 24 hours to 11:01 pm PST (07:01 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 1.7 earthquake was recorded 7 km (4 mi) west-northwest of Fontana, CA, at 7:48 pm PST on 27 January 2018 (03:48 UTC), 8.5 km deep.
USGS: 5km WNW of Fontana, CA
in Fontana, CA · 84 km (52 mi) E of Los Angeles, CA
- When
- 7:48 pm PST on 27 January 2018 ()
- Where
- 7 km (4 mi) west-northwest of Fontana, CA · earthquakes near Fontana
- Magnitude
- M 1.7 (ml)
- Depth
- 8.5 km below the surface
- Felt
- no reports yet
- Nearest
- Orange County, 54 km SSW
- Nearest mapped fault
- Red Hill-Etiwanda Avenue fault, 5 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 3208 days ago
Earthquake alerts for Fontana, CA
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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 9 km (6 mi) from the epicentre. In Fontana, 7 km away, the estimate is intensity II (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 7 km, intensity II · Rancho Cucamonga 8 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 11 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 1,400,000× the energy of this one
- Magna, Utah 2020 M 5.7 970,000× the energy of this one
- Around the size people start to feel M 3.0 86× the energy of this one
- This earthquake M 1.7 about 11 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 12 earthquakes of M5 or more within 50 km; the five largest:
- 6.2 3 km SE of San Bernardino, California · 23 km E of this epicentre
- 6.0 The 1910 Lake Elsinore, California Earthquake · 47 km SSE of this epicentre
- 5.8 The 1991 Sierra Madre, California Earthquake · 48 km WNW of this epicentre
- 5.6 7km ENE of Running Springs, CA · 46 km ENE of this epicentre
- 5.5 The 1990 Upland, California Earthquake · 18 km WNW 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 34.1092, -117.5103. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Orange County, CA | 54 km (34 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
52 earthquakes have been recorded within 50 km since this one.
- 1.8 6km SSE of Loma Linda, CA
- 1.7 10km WNW of Big Bear Lake, CA
- 1.7 8km SSE of Home Gardens, CA
- 1.6 12km NE of Trabuco Canyon, CA
- 1.6 8km N of Fontana, CA
- 2.2 5km NNW of Mountain View Acres, CA
- 2.5 2km NE of Redlands, CA
- 1.9 2km NE of Redlands, CA
- 1.8 8km ESE of Wrightwood, CA
- 1.6 2km NE of Redlands, CA
- 2.5 3km ENE of Upland, CA
- 2.3 5km SSE of Mentone, CA
- 2.6 1km SSW of Loma Linda, CA
- 1.6 1km E of Yorba Linda, CA
- 1.6 12km NE of Trabuco Canyon, 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.