Earthquake · reviewed by a seismologist
M 1.2ml
Earthquake near Rancho Cucamonga, CA
USGS: 4 km N of Rancho Cucamonga, CA
in Rancho Cucamonga, CA · 78 km (49 mi) ENE of Los Angeles, CA
- When
- 8:19 am PDT on 1 October 2026 ()
- Where
- 6 km (4 mi) NNE of Rancho Cucamonga, CA · earthquakes near Rancho Cucamonga
- Magnitude
- M 1.2 (ml)
- Depth
- 8.5 km below the surface
- Felt
- no reports yet
- Nearest
- Orange County, 57 km SSW
- Nearest mapped fault
- Sierra Madre fault, 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 34 hours ago
A magnitude 1.2 earthquake was recorded 6 km (4 mi) NNE of Rancho Cucamonga, CA, at 8:19 am PDT on 1 October 2026 (15:19 UTC). This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.
Earthquakes near other towns within 30 km: San Antonio Heights, Upland, Ontario, Montclair, Fontana, Claremont.
How big was it?
This earthquake released about 1.7 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.2 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 9,100,000× the energy of this one
- Magna, Utah 2020 M 5.7 6,500,000× the energy of this one
- Around the size people start to feel M 3.0 580× the energy of this one
- This earthquake M 1.2 about 1.7 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
The largest earthquake within 50 km since 2016 was M 4.5 on 2020-09-19 — about 120,000 times the energy of this one.
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 · 30 km ESE of this epicentre
- 5.9 The 1987 Whittier Narrows, California Earthquake · 48 km WSW of this epicentre
- 5.8 The 1991 Sierra Madre, California Earthquake · 40 km WNW of this epicentre
- 5.5 The 1990 Upland, California Earthquake · 11 km W of this epicentre
- 5.4 5km S of Chino Hills, CA · 29 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 34.1567, -117.5747. 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 | 63 km (39 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
4 earthquakes have been recorded within 50 km since this one.
- 1.0 8 km S of Llano, CA
- 1.2 2 km SE of Home Gardens, CA
- 1.5 5 km SSE of Home Gardens, CA
- 1.3 7 km SSE of Home Gardens, 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.
Revisions
USGS refines a solution as more stations report. Every change we have seen is listed here.
| What changed | From | To | When |
|---|---|---|---|
| review status | automatic | reviewed | |
| longitude | -117.57 | -117.57 | |
| latitude | 34.16 | 34.16 | |
| depth | 8.58 | 8.49 | |
| magnitude | 1.16 | 1.16 |
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.