Earthquake · reviewed by a seismologist
M 2.7ml
Earthquake near Redlands, CA
No earthquake was likely felt in Redlands in the 24 hours to 8:20 am PST (16:20 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 2.7 earthquake was recorded 3 km (2 mi) west-southwest of Redlands, CA, at 12:03 am PDT on 20 April 2021 (07:03 UTC), 16 km deep. 27 people have reported feeling it to USGS.
USGS: 3km WSW of Redlands, CA
in Redlands, CA · 111 km (69 mi) E of Los Angeles, CA
- When
- 12:03 am PDT on 20 April 2021 ()
- Where
- 3 km (2 mi) west-southwest of Redlands, CA · earthquakes near Redlands
- Magnitude
- M 2.7 (ml)
- Depth
- 16 km below the surface
- Felt
- 27 reports · strongest reported intensity III
- Nearest
- Orange County, 67 km SW
- Nearest mapped fault
- Crafton Hills fault, 2 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 1958 days ago
Earthquake alerts for Redlands, CA
Get a notification in this browser when USGS records an earthquake near Redlands, CA. No account or email needed.
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 small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.
At this magnitude and depth, people at rest would likely notice it out to about 20 km (12 mi) from the epicentre. In Redlands, 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: Redlands 3 km, intensity II · Loma Linda 5 km, intensity II · Mentone 7 km, intensity II · Highland 9 km, intensity II · Colton 10 km, intensity II · San Bernardino 10 km, intensity II · Moreno Valley 12 km, intensity II · Yucaipa 15 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 330 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.7 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 46,000× the energy of this one
- Magna, Utah 2020 M 5.7 33,000× the energy of this one
- Around the size people start to feel M 3.0 2.9× the energy of this one
- This earthquake M 2.7 about 330 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 500 times the energy of this one.
Before 2016, the USGS record lists 24 earthquakes of M5 or more within 50 km; the five largest:
- 6.7 The 1918 San Jacinto, California Earthquake · 38 km SE of this epicentre
- 6.3 The 1992 Big Bear, California Earthquake · 39 km ENE of this epicentre
- 6.2 3 km SE of San Bernardino, California · 7 km NW of this epicentre
- 6.0 The 1910 Lake Elsinore, California Earthquake · 42 km SSW of this epicentre
- 5.6 7km ENE of Running Springs, CA · 27 km NE 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 34.0450, -117.2100. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Orange County, CA | 67 km (41 mi) | SW | earthquakes near Orange County |
| Los Angeles County, CA | 98 km (61 mi) | W | earthquakes near Los Angeles County |
| Riverside County, CA | 117 km (73 mi) | ESE | earthquakes near Riverside County |
| San Diego County, CA | 120 km (75 mi) | SSE | earthquakes near San Diego County |
| San Bernardino County, CA | 131 km (81 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
46 earthquakes have been recorded within 50 km since this one.
- 1.6 12km NW of Big Bear Lake, CA
- 1.6 7km E of Calimesa, CA
- 1.8 6km SE of Cabazon, CA
- 2.1 11km E of Yorba Linda, CA
- 1.8 5km S of Banning, CA
- 2.1 6km ESE of Valle Vista, CA
- 1.8 5km SSE of Home Gardens, CA
- 1.5 1km NNE of Loma Linda, CA
- 1.8 7km SSE of Home Gardens, CA
- 1.5 6km N of Banning, CA
- 1.6 4km SW of Rancho Cucamonga, CA
- 1.5 11km E of Yorba Linda, CA
- 1.6 7km NNW of Mira Loma, CA
- 1.6 4km ENE of Big Bear City, CA
- 1.9 5km SE 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.
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.