Earthquake · reviewed by a seismologist
M 3.5ml
Earthquake near Rancho Cucamonga, CA
No earthquake was likely felt in Rancho Cucamonga in the 24 hours to 3:37 am PST (11:37 UTC). The last one was M 2.0, 10 km (6 mi) E, at 2:35 am PDT on 23 October 2026, estimated intensity II (weak) in town; 3 felt reports to USGS. Every earthquake near Rancho Cucamonga
This page: a magnitude 3.5 earthquake was recorded 8 km (5 mi) north-northwest of Rancho Cucamonga, CA, at 7:28 pm PDT on 23 May 2016 (02:28 UTC), 10 km deep. 378 people have reported feeling it to USGS.
USGS: 7km NW of Rancho Cucamonga, CA
7 km (4 mi) NNE of Upland, CA · 74 km (46 mi) ENE of Los Angeles, CA
- When
- 7:28 pm PDT on 23 May 2016 ()
- Where
- 8 km (5 mi) north-northwest of Rancho Cucamonga, CA · earthquakes near Rancho Cucamonga
- Magnitude
- M 3.5 (ml)
- Depth
- 10 km below the surface
- Felt
- 378 reports · strongest reported intensity IV
- Measured shaking
- intensity V (ShakeMap)
- Nearest
- Orange County, 57 km SSW
- Nearest mapped fault
- San Jacinto fault, 4 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 2413 days ago
Earthquake alerts for Rancho Cucamonga, CA
Get a notification in this browser when USGS records an earthquake near Rancho Cucamonga, 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 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 60 km (37 mi) from the epicentre. In Rancho Cucamonga, 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: Rancho Cucamonga 8 km, intensity III · Upland 8 km, intensity III · Claremont 12 km, intensity III · Montclair 12 km, intensity III · Ontario 12 km, intensity III · La Verne 15 km, intensity III · Pomona 17 km, intensity III · San Dimas 18 km, intensity III. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 2.3 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.5 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 75,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 3,300× the energy of this one
- Magna, Utah 2020 M 5.7 2,400× the energy of this one
- This earthquake M 3.5 about 2.3 tons of TNT
- Around the size people start to feel M 3.0 this one released 4.7× 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
No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.
Before 2016, the USGS record lists 10 earthquakes of M5 or more within 50 km; the five largest:
- 6.2 3 km SE of San Bernardino, California · 35 km ESE of this epicentre
- 5.9 The 1987 Whittier Narrows, California Earthquake · 43 km WSW of this epicentre
- 5.8 The 1991 Sierra Madre, California Earthquake · 35 km WNW of this epicentre
- 5.5 The 1990 Upland, California Earthquake · 7 km WSW of this epicentre
- 5.4 5km S of Chino Hills, CA · 28 km SSW 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 34.1717, -117.6312. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Orange County, CA | 57 km (35 mi) | SSW | earthquakes near Orange County |
| Los Angeles County, CA | 58 km (36 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
54 earthquakes have been recorded within 50 km since this one.
- 1.9 1km W of San Gabriel, CA
- 1.5 8km SSW of Lytle Creek, CA
- 1.8 2km SW of Mira Loma, CA
- 2.0 7km SSW of Devore, CA
- 1.7 7km SSW of Devore, CA
- 1.6 2km SSE of Loma Linda, CA
- 2.4 2km NE of Colton, CA
- 1.6 4km NNW of Glen Avon, CA
- 1.7 1km S of Ontario, CA
- 2.9 3km WNW of Yorba Linda, CA
- 1.6 2km NE of Placentia, CA
- 1.5 2km SW of Mira Loma, CA
- 1.8 4km SE of Home Gardens, CA
- 2.0 1km ESE of Loma Linda, CA
- 1.5 6km 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.