QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7ml

Earthquake near Redlands, CA

No earthquake was likely felt in Redlands in the 24 hours to 12:41 pm PST (20:41 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 1.7 earthquake was recorded 6 km (4 mi) south of Redlands, CA, at 12:57 pm PDT on 19 March 2021 (19:57 UTC), 15 km deep. 1 person has reported feeling it to USGS.

USGS: 6km S of Redlands, CA

6 km (4 mi) SSW of Redlands, CA · 112 km (70 mi) E of Los Angeles, CA

12:57 pm PDT, Mar 19, 2021 · · 15 km deep · released about 9.6 lb of TNT

10 km30 km60 km120 km N Orange County 65 kmLos Angeles County 101 kmRiverside County 114 kmSan Diego County 115 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
12:57 pm PDT on 19 March 2021 ()
Where
6 km (4 mi) south of Redlands, CA · earthquakes near Redlands
Magnitude
M 1.7 (ml)
Depth
15 km below the surface
Felt
1 report · 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 2064 days ago

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 Redlands, 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.

Earthquakes near other towns within 30 km: Moreno Valley, Loma Linda, Mentone, Calimesa, Grand Terrace, Highgrove.

How big was it?

This earthquake released about 9.6 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.

  1. Mineral, Virginia 2011 M 5.8 1,600,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,100,000× the energy of this one
  3. Around the size people start to feel M 3.0 99× the energy of this one
  4. This earthquake M 1.7 about 9.6 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 17,000 times the energy of this one.

Before 2016, the USGS record lists 24 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.7 The 1918 San Jacinto, California Earthquake · 33 km SE of this epicentre
  2. 6.3 The 1992 Big Bear, California Earthquake · 40 km NE of this epicentre
  3. 6.2 3 km SE of San Bernardino, California · 12 km NNW of this epicentre
  4. 6.0 The 1910 Lake Elsinore, California Earthquake · 39 km SSW of this epicentre
  5. 5.6 7km ENE of Running Springs, CA · 30 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 34.0007, -117.1905. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Orange County, CA 65 km (40 mi) WSW earthquakes near Orange County
Los Angeles County, CA 101 km (63 mi) WNW earthquakes near Los Angeles County
Riverside County, CA 114 km (71 mi) ESE earthquakes near Riverside County
San Diego County, CA 115 km (72 mi) SSE earthquakes near San Diego County
San Bernardino County, CA 133 km (82 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

49 earthquakes have been recorded within 50 km since this one.

  1. 2.6 1km N of Yucaipa, CA
  2. 1.6 7km SSE of Home Gardens, CA
  3. 1.5 12km SSW of Lucerne Valley, CA
  4. 2.0 3km NNW of Fontana, CA
  5. 1.5 9km S of Banning, CA
  6. 1.5 9km N of Banning, CA
  7. 2.1 4km NE of Running Springs, CA
  8. 1.6 1km N of Wildomar, CA
  9. 1.9 4km SE of Home Gardens, CA
  10. 1.9 4km SE of Yucaipa, CA
  11. 1.6 6km SE of Loma Linda, CA
  12. 1.8 11km E of Yorba Linda, CA
  13. 2.7 3km WSW of Redlands, CA
  14. 1.5 6km NNW of San Jacinto, CA
  15. 1.6 9km SE of Valle Vista, 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

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.