QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

Earthquake near Calimesa, CA

No earthquake was likely felt in Calimesa in the 24 hours to 7:12 am PST (15:12 UTC). The last one was M 2.0, 7 km (4 mi) WSW, at 10:33 pm PST on 2 November 2026, estimated intensity II (weak) in town. Every earthquake near Calimesa

This page: a magnitude 1.8 earthquake was recorded 4 km (3 mi) east-southeast of Calimesa, CA, at 8:07 am PST on 27 November 2021 (16:07 UTC), 14 km deep.

USGS: 3km E of Calimesa, CA

5 km (3 mi) SSE of Yucaipa, CA · 128 km (80 mi) E of Los Angeles, CA

8:07 am PST, Nov 27, 2021 · · 14 km deep · released about 15 lb of TNT

10 km30 km60 km120 km N Orange County 78 kmRiverside County 98 kmSan Diego County 110 kmLos Angeles County 117 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
8:07 am PST on 27 November 2021 ()
Where
4 km (3 mi) east-southeast of Calimesa, CA · earthquakes near Calimesa
Magnitude
M 1.8 (ml)
Depth
14 km below the surface
Felt
no reports yet
Nearest
Orange County, 78 km WSW
Nearest mapped fault
San Gorgonio Pass fault, 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 1809 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 Calimesa, 4 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: Cherry Valley, Yucaipa, Beaumont, Mentone, Banning, Redlands.

How big was it?

This earthquake released about 15 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 710,000× the energy of this one
  3. Around the size people start to feel M 3.0 63× the energy of this one
  4. This earthquake M 1.8 about 15 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 11,000 times the energy of this one.

Before 2016, the USGS record lists 23 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.7 The 1918 San Jacinto, California Earthquake · 26 km S of this epicentre
  2. 6.3 The 1992 Big Bear, California Earthquake · 30 km NE of this epicentre
  3. 6.2 3 km SE of San Bernardino, California · 25 km WNW of this epicentre
  4. 6.0 The 1910 Lake Elsinore, California Earthquake · 48 km SW of this epicentre
  5. 6.0 The 1986 North Palm Springs, California Earthquake · 38 km E 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 33.9900, -117.0207. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Orange County, CA 78 km (49 mi) WSW earthquakes near Orange County
Riverside County, CA 98 km (61 mi) ESE earthquakes near Riverside County
San Diego County, CA 110 km (68 mi) SSE earthquakes near San Diego County
Los Angeles County, CA 117 km (72 mi) WNW earthquakes near Los Angeles County
San Bernardino County, CA 123 km (77 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

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

  1. 1.5 2km S of Valle Vista, CA
  2. 3.0 2km SSW of Valle Vista, CA
  3. 2.2 13km WNW of Anza, CA
  4. 1.7 2km NNW of Loma Linda, CA
  5. 2.5 11km E of Big Bear City, CA
  6. 2.4 10km NNW of Idyllwild, CA
  7. 3.5 10km NNW of Idyllwild, CA
  8. 1.6 2km ESE of Loma Linda, CA
  9. 1.6 6km SW of Idyllwild, CA
  10. 2.0 4km SE of Home Gardens, CA
  11. 2.0 4km ENE of Colton, CA
  12. 1.9 1km SE of Loma Linda, CA
  13. 1.8 8km N of Big Bear City, CA
  14. 1.6 10km NW of Anza, CA
  15. 1.6 8km SSE 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

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