QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1ml

Earthquake near Running Springs, CA

No earthquake was likely felt in Running Springs in the 24 hours to 9:03 am PST (17:03 UTC). The last one was M 2.0, 13 km (8 mi) WSW, at 3:40 pm PDT on 22 September 2026, estimated intensity II (weak) in town; 14 felt reports to USGS. Every earthquake near Running Springs

This page: a magnitude 2.1 earthquake was recorded 4 km (2 mi) northeast of Running Springs, CA, at 7:25 pm PDT on 25 April 2021 (02:25 UTC), 1.8 km deep. 3 people have reported feeling it to USGS.

USGS: 4km NE of Running Springs, CA

15 km (9 mi) NNE of Highland, CA · 125 km (78 mi) E of Los Angeles, CA

7:25 pm PDT, Apr 25, 2021 · · 1.8 km deep · released about 40 lb of TNT

Every earthquake near Running Springs Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Orange County 89 kmSan Bernardino County 108 kmLos Angeles County 109 kmRiverside County 113 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
7:25 pm PDT on 25 April 2021 ()
Where
4 km (2 mi) northeast of Running Springs, CA · earthquakes near Running Springs
Magnitude
M 2.1 (ml)
Depth
1.8 km below the surface
Felt
3 reports · strongest reported intensity III
Nearest
Orange County, 89 km SW
Nearest mapped fault
San Andreas fault, 11 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 2025 days ago

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 17 km (11 mi) from the epicentre. In Running Springs, 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.

Likely felt in: Lake Arrowhead 11 km, intensity II · Big Bear Lake 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 40 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 5.8 380,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 270,000× the energy of this one
  3. Around the size people start to feel M 3.0 24× the energy of this one
  4. This earthquake M 2.1 about 40 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 4,100 times the energy of this one.

Before 2016, the USGS record lists 17 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.3 The 1992 Big Bear, California Earthquake · 23 km E of this epicentre
  2. 6.2 3 km SE of San Bernardino, California · 23 km SW of this epicentre
  3. 5.6 7km ENE of Running Springs, CA · 4 km ENE of this epicentre
  4. 5.5 11km SSE of Big Bear Lake, California · 22 km ESE of this epicentre
  5. 5.3 Near San Bernardino, California · 4 km SW 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 34.2275, -117.0763. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Orange County, CA 89 km (55 mi) SW earthquakes near Orange County
San Bernardino County, CA 108 km (67 mi) NE earthquakes near San Bernardino County
Los Angeles County, CA 109 km (68 mi) W earthquakes near Los Angeles County
Riverside County, CA 113 km (70 mi) ESE earthquakes near Riverside County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

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

  1. 1.6 10km N of Big Bear Lake, CA
  2. 1.5 3km ENE of Big Bear City, CA
  3. 2.0 5km ESE of Yucaipa, CA
  4. 2.6 3km ENE of San Jacinto, CA
  5. 1.8 5km S of Devore, CA
  6. 1.5 10km ENE of Cabazon, CA
  7. 1.9 7km ENE of Nuevo, CA
  8. 1.7 7km ENE of Nuevo, CA
  9. 1.8 4km SW of Redlands, CA
  10. 1.7 5km SSW of Redlands, CA
  11. 1.5 4km SE of Loma Linda, CA
  12. 2.2 3km WSW of Rubidoux, CA
  13. 1.9 2km SSW of Rancho Cucamonga, CA
  14. 2.1 3km W of Calimesa, CA
  15. 2.3 7km NNW of Big Bear Lake, 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.