QuakeIndex

quarry blast · reviewed by a seismologist

M 1.5ml

Earthquake near Lucerne Valley, CA

No earthquake was likely felt in Lucerne Valley in the 24 hours to 6:16 am PST (14:16 UTC). The last one was M 2.6, 19 km (12 mi) SSE, at 1:40 am PDT on 6 October 2026, estimated intensity II (weak) in town; 18 felt reports to USGS. Every earthquake near Lucerne Valley

No: USGS classifies this as a quarry blast, not an earthquake. A magnitude 1.5 quarry blast was recorded 12 km (7 mi) south-southwest of Lucerne Valley, CA, at 9:46 am PDT on 30 April 2021 (16:46 UTC), less than 1 km deep.

USGS: 12km SSW of Lucerne Valley, CA

28 km (17 mi) SE of Apple Valley, CA · 133 km (83 mi) ENE of Los Angeles, CA

9:46 am PDT, Apr 30, 2021 · · -1.5 km deep · released about 5.7 lb of TNT

Every earthquake near Lucerne Valley Felt it? Tell USGS Check my area
10 km30 km60 km120 km N San Bernardino County 95 kmOrange County 102 kmRiverside County 116 kmLos Angeles County 116 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
9:46 am PDT on 30 April 2021 ()
Where
12 km (7 mi) south-southwest of Lucerne Valley, CA · earthquakes near Lucerne Valley
Magnitude
M 1.5 (ml)
Depth
-1.5 km below the surface
Felt
no reports yet
Nearest
San Bernardino County, 95 km NE
Nearest mapped fault
North Frontal thrust system, 9 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 2022 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 10 km (6 mi) from the epicentre. In Lucerne Valley, 12 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: Big Bear Lake, Running Springs, Big Bear City, Lake Arrowhead, Apple Valley, Crestline.

USGS catalogues this as quarry blast, not an earthquake.

How big was it?

This earthquake released about 5.7 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,600,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,900,000× the energy of this one
  3. Around the size people start to feel M 3.0 170× the energy of this one
  4. This earthquake M 1.5 about 5.7 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 29,000 times the energy of this one.

Before 2016, the USGS record lists 16 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.3 The 1992 Big Bear, California Earthquake · 23 km SE of this epicentre
  2. 6.2 3 km SE of San Bernardino, California · 36 km SW of this epicentre
  3. 5.6 7km ENE of Running Springs, CA · 12 km SSW of this epicentre
  4. 5.5 11km SSE of Big Bear Lake, California · 25 km SE of this epicentre
  5. 5.4 26km NNW of Yucca Valley, CA · 46 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 34.3445, -117.0143. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
San Bernardino County, CA 95 km (59 mi) NE earthquakes near San Bernardino County
Orange County, CA 102 km (64 mi) SW earthquakes near Orange County
Riverside County, CA 116 km (72 mi) SE earthquakes near Riverside County
Los Angeles County, CA 116 km (72 mi) W earthquakes near Los Angeles County

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

Aftershocks so far

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

  1. 2.0 5km N of Running Springs, CA
  2. 3.0 5km NNE of Running Springs, CA
  3. 3.4 4km NNW of Fontana, CA
  4. 2.2 4km NW of Fontana, CA
  5. 2.3 5km S of Mentone, CA
  6. 2.2 4km NW of Muscoy, CA
  7. 1.5 3km NE of Grand Terrace, CA
  8. 1.6 4km ENE of Big Bear City, CA
  9. 1.5 4km SSW of Redlands, CA
  10. 1.5 12km N of Big Bear City, CA
  11. 2.6 12km N of Big Bear City, CA
  12. 1.7 6km NNE of Big Bear City, CA
  13. 1.6 10km N of Big Bear Lake, CA
  14. 1.5 3km ENE of Big Bear City, CA
  15. 2.0 5km ESE of Yucaipa, 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.