Earthquake · reviewed by a seismologist
M 2.4ml
Earthquake near Upland, CA
No earthquake was likely felt in Upland in the 24 hours to 3:28 am PST (11:28 UTC). The last one was M 1.7, 10 km (6 mi) SSE, at 2:48 pm PDT on 9 October 2026, estimated intensity II (weak) in town. Every earthquake near Upland
This page: a magnitude 2.4 earthquake was recorded 3 km (2 mi) east of Upland, CA, at 5:26 am PST on 23 December 2019 (13:26 UTC), 12 km deep. 43 people have reported feeling it to USGS.
USGS: 3km E of Upland, CA
in Upland, CA · 74 km (46 mi) E of Los Angeles, CA
- When
- 5:26 am PST on 23 December 2019 ()
- Where
- 3 km (2 mi) east of Upland, CA · earthquakes near Upland
- Magnitude
- M 2.4 (ml)
- Depth
- 12 km below the surface
- Felt
- 43 reports · strongest reported intensity III
- Nearest
- Orange County, 49 km SSW
- Nearest mapped fault
- Red Hill-Etiwanda Avenue fault, 3 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 757 days ago
Earthquake alerts for Upland, 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, people at rest would likely notice it out to about 18 km (11 mi) from the epicentre. In Upland, 3 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: Rancho Cucamonga 3 km, intensity II · Upland 3 km, intensity II · Ontario 5 km, intensity II · Montclair 7 km, intensity II · Claremont 9 km, intensity II · Chino 11 km, intensity II · Pomona 13 km, intensity II · La Verne 14 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 130 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.4 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 110,000× the energy of this one
- Magna, Utah 2020 M 5.7 80,000× the energy of this one
- Around the size people start to feel M 3.0 7.2× the energy of this one
- This earthquake M 2.4 about 130 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 4.4 on 2018-08-29 — about 840 times the energy of this one.
Before 2016, the USGS record lists 15 earthquakes of M5 or more within 50 km; the five largest:
- 6.2 3 km SE of San Bernardino, California · 33 km E of this epicentre
- 6.0 The 1910 Lake Elsinore, California Earthquake · 49 km SSE of this epicentre
- 5.9 The 1987 Whittier Narrows, California Earthquake · 43 km W of this epicentre
- 5.8 The 1991 Sierra Madre, California Earthquake · 39 km WNW of this epicentre
- 5.5 The 1990 Upland, California Earthquake · 9 km NW 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 34.0968, -117.6182. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Orange County, CA | 49 km (30 mi) | SSW | earthquakes near Orange County |
| Los Angeles County, CA | 60 km (37 mi) | W | earthquakes near Los Angeles County |
| San Diego County, CA | 143 km (89 mi) | SSE | 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.
- 1.7 5km SSE of Home Gardens, CA
- 2.0 2km SSW of San Bernardino, CA
- 1.6 8km WNW of Lytle Creek, CA
- 1.6 2km ESE of Loma Linda, CA
- 1.6 7km NW of Glen Avon, CA
- 1.5 5km SE of Lytle Creek, CA
- 1.8 6km E of Ontario, CA
- 1.7 2km ENE of Villa Park, CA
- 1.6 7km S of Redlands, CA
- 1.8 4km ENE of Lake Arrowhead, CA
- 2.0 4km SSE of Yorba Linda, CA
- 2.2 8 km E of Yorba Linda, CA
- 1.6 4 km SE of Home Gardens, CA
- 1.5 11km ENE of North Tustin, CA
- 1.7 5km NW of Mira Loma, 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.