Earthquake · reviewed by a seismologist
M 2.4ml
Earthquake near Redlands, CA
No earthquake was likely felt in Redlands in the 24 hours to 5:14 am PST (13:14 UTC). The last one was M 2.0, 9 km (5 mi) SSE, at 10:33 pm PST on 2 November 2026, estimated intensity II (weak) in town. Every earthquake near Redlands
This page: a magnitude 2.4 earthquake was recorded 7 km (5 mi) south of Redlands, CA, at 1:17 pm PDT on 17 October 2021 (20:17 UTC), 14 km deep. 2 people have reported feeling it to USGS.
USGS: 7km S of Redlands, CA
7 km (4 mi) S of Redlands, CA · 113 km (70 mi) E of Los Angeles, CA
- When
- 1:17 pm PDT on 17 October 2021 ()
- Where
- 7 km (5 mi) south of Redlands, CA · earthquakes near Redlands
- Magnitude
- M 2.4 (ml)
- Depth
- 14 km below the surface
- Felt
- 2 reports · strongest reported intensity II
- Nearest
- Orange County, 65 km WSW
- Nearest mapped fault
- San Jacinto fault, under 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 1557 days ago
Earthquake alerts for Redlands, CA
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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 16 km (10 mi) from the epicentre. In Redlands, 7 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: Moreno Valley 7 km, intensity II · Redlands 7 km, intensity II · Loma Linda 10 km, intensity II · Mentone 10 km, intensity II · Yucaipa 14 km, intensity II · Colton 15 km, intensity II · Highland 16 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 140 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 78,000× the energy of this one
- Around the size people start to feel M 3.0 6.9× the energy of this one
- This earthquake M 2.4 about 140 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 2018-05-08 — about 1,200 times the energy of this one.
Before 2016, the USGS record lists 23 earthquakes of M5 or more within 50 km; the five largest:
- 6.7 The 1918 San Jacinto, California Earthquake · 32 km SE of this epicentre
- 6.3 The 1992 Big Bear, California Earthquake · 40 km NE of this epicentre
- 6.2 3 km SE of San Bernardino, California · 13 km NNW of this epicentre
- 6.0 The 1910 Lake Elsinore, California Earthquake · 38 km SSW of this epicentre
- 5.6 7km ENE of Running Springs, CA · 31 km NNE 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 33.9892, -117.1810. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Orange County, CA | 65 km (40 mi) | WSW | earthquakes near Orange County |
| Los Angeles County, CA | 102 km (63 mi) | WNW | earthquakes near Los Angeles County |
| Riverside County, CA | 113 km (70 mi) | ESE | earthquakes near Riverside County |
| San Diego County, CA | 114 km (71 mi) | SSE | earthquakes near San Diego County |
| San Bernardino County, CA | 133 km (83 mi) | NE | earthquakes near San Bernardino County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
48 earthquakes have been recorded within 50 km since this one.
- 1.9 5km SSE of Home Gardens, CA
- 2.7 6km SSW of Redlands, CA
- 2.0 13km SE of Big Bear City, CA
- 1.8 7km S of Redlands, CA
- 1.9 3km ESE of Ontario, CA
- 1.6 11km W of Corona, CA
- 1.9 9km SE of Valle Vista, CA
- 1.9 3km N of Loma Linda, CA
- 1.8 11km WSW of Morongo Valley, CA
- 1.6 4km W of Yucaipa, CA
- 1.6 5km SSE of Loma Linda, CA
- 2.0 4km W of Yucaipa, CA
- 1.8 3km E of Calimesa, CA
- 2.6 9km ESE of Big Bear City, CA
- 1.6 6km E of Calimesa, 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.