QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1ml

Earthquake near Colton, CA

No earthquake was likely felt in Colton in the 24 hours to 7:04 am PST (15:04 UTC). The last one was M 2.1, 8 km (5 mi) SE, at 10:40 am PDT on 31 October 2026, estimated intensity II (weak) in town. Every earthquake near Colton

This page: a magnitude 2.1 earthquake was recorded in Colton, CA, at 4:51 am PDT on 8 October 2017 (11:51 UTC), 18 km deep. 2 people have reported feeling it to USGS.

USGS: 2km SE of Colton, CA

in Colton, CA · 102 km (64 mi) E of Los Angeles, CA

4:51 am PDT, Oct 8, 2017 · · 18 km deep · released about 49 lb of TNT

10 km30 km60 km120 km N Orange County 62 kmLos Angeles County 90 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
4:51 am PDT on 8 October 2017 ()
Where
in Colton, CA · earthquakes near Colton
Magnitude
M 2.1 (ml)
Depth
18 km below the surface
Felt
2 reports · strongest reported intensity II
Nearest
Orange County, 62 km SW
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 1558 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. 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: Grand Terrace, Loma Linda, San Bernardino, Highgrove, Rialto, Bloomington.

How big was it?

This earthquake released about 49 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 310,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 220,000× the energy of this one
  3. Around the size people start to feel M 3.0 19× the energy of this one
  4. This earthquake M 2.1 about 49 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 2016-01-06 — about 2,400 times the energy of this one.

Before 2016, the USGS record lists 20 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.7 The 1918 San Jacinto, California Earthquake · 45 km SE of this epicentre
  2. 6.3 The 1992 Big Bear, California Earthquake · 46 km ENE of this epicentre
  3. 6.2 3 km SE of San Bernardino, California · 5 km NE of this epicentre
  4. 6.0 The 1910 Lake Elsinore, California Earthquake · 41 km SSW of this epicentre
  5. 5.6 7km ENE of Running Springs, CA · 31 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 34.0632, -117.3013. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Orange County, CA 62 km (38 mi) SW earthquakes near Orange County
Los Angeles County, CA 90 km (56 mi) W earthquakes near Los Angeles County
San Diego County, CA 125 km (78 mi) SSE earthquakes near San Diego County
Riverside County, CA 125 km (78 mi) ESE earthquakes near Riverside County
San Bernardino County, CA 135 km (84 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

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

  1. 2.1 1km S of Loma Linda, CA
  2. 1.9 4km SE of Home Gardens, CA
  3. 1.9 5km SE of Loma Linda, CA
  4. 1.8 4km N of Beaumont, CA
  5. 2.2 4km NNW of Valle Vista, CA
  6. 1.9 5km NNW of Lake Elsinore, CA
  7. 1.8 2km NE of Redlands, CA
  8. 1.7 13km NNE of Yucaipa, CA
  9. 1.6 8km ESE of Yorba Linda, CA
  10. 1.6 3km SE of Loma Linda, CA
  11. 2.6 3km SE of Loma Linda, CA
  12. 1.6 3km ESE of Loma Linda, CA
  13. 2.7 5km E of Calimesa, CA
  14. 2.7 2km ESE of Loma Linda, CA
  15. 1.5 5km ENE of Rancho Cucamonga, 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.