QuakeIndex

Earthquake · reviewed by a seismologist

M 2.5ml

Earthquake near San Bernardino, CA

No earthquake was likely felt in San Bernardino in the 24 hours to 1:53 pm PST (21:53 UTC). The last one was M 2.1, 9 km (6 mi) SSE, at 10:40 am PDT on 31 October 2026, estimated intensity II (weak) in town. Every earthquake near San Bernardino

This page: a magnitude 2.5 earthquake was recorded 3 km (2 mi) west of San Bernardino, CA, at 6:23 am PST on 12 March 2021 (14:23 UTC), 17 km deep. 16 people have reported feeling it to USGS.

USGS: 3km SW of San Bernardino, CA

in San Bernardino, CA

6:23 am PST, Mar 12, 2021 · · 17 km deep · released about 170 lb of TNT

10 km30 km60 km120 km N Orange County 64 kmLos Angeles County 87 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
6:23 am PST on 12 March 2021 ()
Where
3 km (2 mi) west of San Bernardino, CA · earthquakes near San Bernardino
Magnitude
M 2.5 (ml)
Depth
17 km below the surface
Felt
16 reports · strongest reported intensity IV
Nearest
Orange County, 64 km SW
Nearest mapped fault
San Jacinto 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 1847 days ago

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 15 km (9 mi) from the epicentre. In San Bernardino, 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: San Bernardino 3 km, intensity II · Colton 4 km, intensity II · Rialto 5 km, intensity II · Muscoy 6 km, intensity II · Loma Linda 9 km, intensity II · Highland 10 km, intensity II · Fontana 11 km, intensity II · Redlands 14 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 170 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 89,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 63,000× the energy of this one
  3. Around the size people start to feel M 3.0 5.6× the energy of this one
  4. This earthquake M 2.5 about 170 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 680 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. 6.3 The 1992 Big Bear, California Earthquake · 46 km ENE of this epicentre
  2. 6.2 3 km SE of San Bernardino, California · 6 km ESE of this epicentre
  3. 6.0 The 1910 Lake Elsinore, California Earthquake · 46 km S of this epicentre
  4. 5.6 7km ENE of Running Springs, CA · 29 km ENE of this epicentre
  5. 5.5 The 1990 Upland, California Earthquake · 35 km W 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 34.1098, -117.3173. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Orange County, CA 64 km (40 mi) SW earthquakes near Orange County
Los Angeles County, CA 87 km (54 mi) W earthquakes near Los Angeles County
San Bernardino County, CA 133 km (83 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

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

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