Earthquake · reviewed by a seismologist
M 1.7ml
Earthquake near Pomona, CA
No earthquake was likely felt in Pomona in the 24 hours to 11:45 pm PST (07:45 UTC). The last one was M 3.2, 16 km (10 mi) ESE, at 5:37 am PDT on 2 September 2026, estimated intensity III (weak) in town; 730 felt reports to USGS. Every earthquake near Pomona
This page: a magnitude 1.7 earthquake was recorded 4 km (3 mi) west of Pomona, CA, at 7:26 am PST on 12 February 2018 (15:26 UTC), 14 km deep.
USGS: 4km W of Pomona, CA
in Pomona, CA · 57 km (35 mi) E of Los Angeles, CA
- When
- 7:26 am PST on 12 February 2018 ()
- Where
- 4 km (3 mi) west of Pomona, CA · earthquakes near Pomona
- Magnitude
- M 1.7 (ml)
- Depth
- 14 km below the surface
- Felt
- no reports yet
- Nearest
- Orange County, 43 km S
- Nearest mapped fault
- Sierra Madre fault, 7 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 3187 days ago
Earthquake alerts for Pomona, 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 minor earthquake. Quakes this small are rarely felt and do not cause damage.
At this magnitude and depth it was probably too small to be felt, even directly above it. In Pomona, 4 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.
Earthquakes near other towns within 30 km: Diamond Bar, San Dimas, La Verne, Charter Oak, Walnut, Claremont.
How big was it?
This earthquake released about 9.3 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 1,600,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,100,000× the energy of this one
- Around the size people start to feel M 3.0 100× the energy of this one
- This earthquake M 1.7 about 9.3 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 · 50 km E of this epicentre
- 5.9 The 1987 Whittier Narrows, California Earthquake · 26 km W of this epicentre
- 5.8 The 1991 Sierra Madre, California Earthquake · 29 km NW of this epicentre
- 5.5 The 1990 Upland, California Earthquake · 13 km NE of this epicentre
- 5.4 5km S of Chino Hills, CA · 13 km SSE 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 34.0620, -117.7968. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Orange County, CA | 43 km (27 mi) | S | earthquakes near Orange County |
| Los Angeles County, CA | 45 km (28 mi) | WNW | earthquakes near Los Angeles County |
| San Diego County, CA | 149 km (93 mi) | SE | earthquakes near San Diego County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
56 earthquakes have been recorded within 50 km since this one.
- 1.6 12km NE of Trabuco Canyon, CA
- 1.8 3km NNW of Loma Linda, CA
- 1.6 6km NNW of Fontana, CA
- 1.5 1km W of Loma Linda, CA
- 1.9 3km N of Colton, CA
- 1.6 1km SSE of Loma Linda, CA
- 2.6 7km NNW of Fontana, CA
- 2.1 7km NNW of Fontana, CA
- 1.6 5km SE of Home Gardens, CA
- 1.9 3km S of Lytle Creek, CA
- 2.0 3km NNE of Norco, CA
- 2.1 11km NNE of Trabuco Canyon, CA
- 2.5 11km NE of Trabuco Canyon, CA
- 2.4 2km W of Loma Linda, CA
- 1.9 4km WSW of Compton, 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.