Earthquake · reviewed by a seismologist
M 1.9ml
Earthquake near Norco, CA
No earthquake was likely felt in Norco in the 24 hours to 3:35 am PST (11:35 UTC). The last one was M 1.8, 11 km (7 mi) SSE, at 11:31 am PST on 5 November 2026, estimated intensity II (weak) in town. Every earthquake near Norco
This page: a magnitude 1.9 earthquake was recorded 6 km (3 mi) west-southwest of Norco, CA, at 7:59 am PST on 15 December 2019 (15:59 UTC), 3.7 km deep. 7 people have reported feeling it to USGS.
USGS: 6km WSW of Norco, CA
6 km (4 mi) SSW of Eastvale, CA · 75 km (47 mi) E of Los Angeles, CA
- When
- 7:59 am PST on 15 December 2019 ()
- Where
- 6 km (3 mi) west-southwest of Norco, CA · earthquakes near Norco
- Magnitude
- M 1.9 (ml)
- Depth
- 3.7 km below the surface
- Felt
- 7 reports · strongest reported intensity II
- Nearest
- Orange County, 31 km SSW
- Nearest mapped fault
- Elsinore fault, 6 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 2523 days ago
Earthquake alerts for Norco, 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 15 km (9 mi) from the epicentre. In Norco, 6 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: Corona 5 km, intensity II · Norco 6 km, intensity II · Eastvale 7 km, intensity II · Chino 14 km, intensity II · Pedley 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 23 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 660,000× the energy of this one
- Magna, Utah 2020 M 5.7 470,000× the energy of this one
- Around the size people start to feel M 3.0 42× the energy of this one
- This earthquake M 1.9 about 23 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 4,900 times the energy of this one.
Before 2016, the USGS record lists 14 earthquakes of M5 or more within 50 km; the five largest:
- 6.4 The 1933 Long Beach, California Earthquake · 48 km SW of this epicentre
- 6.2 3 km SE of San Bernardino, California · 37 km ENE of this epicentre
- 6.0 The 1910 Lake Elsinore, California Earthquake · 30 km SE of this epicentre
- 5.9 The 1987 Whittier Narrows, California Earthquake · 47 km WNW of this epicentre
- 5.5 The 1990 Upland, California Earthquake · 27 km NNW 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 33.9118, -117.6040. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Orange County, CA | 31 km (19 mi) | SSW | earthquakes near Orange County |
| Los Angeles County, CA | 68 km (42 mi) | WNW | earthquakes near Los Angeles County |
| San Diego County, CA | 125 km (78 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
59 earthquakes have been recorded within 50 km since this one.
- 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
- 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
- 1.6 2km SE of Home Gardens, CA
- 1.5 4km SSE of Lytle Creek, CA
- 1.6 8km N of Claremont, CA
- 1.6 7km N of Claremont, CA
- 2.1 8km N of Claremont, 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.