QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1ml

23km WNW of Ludlow, CA

Yes. A magnitude 2.1 earthquake was recorded 23km WNW of Ludlow, CA, at 6:25 am PDT on 13 July 2021 (13:25 UTC), 3.4 km deep.

· 3.4 km deep · released about 41 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N San Bernardino County 18 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
Magnitude
M 2.1 (ml)
Depth
3.4 km below the surface
Felt
no reports yet
Nearest
San Bernardino County, 18 km E
Nearest mapped fault
Pisgah-Bullion 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 1948 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. 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.

How big was it?

This earthquake released about 41 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 5.8 370,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 260,000× the energy of this one
  3. Around the size people start to feel M 3.0 23× the energy of this one
  4. This earthquake M 2.1 about 41 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 4.3 on 2016-02-20 — about 2,100 times the energy of this one.

Before 2016, the USGS record lists 11 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.1 The 1999 Hector Mine, California Earthquake · 27 km SSE of this epicentre
  2. 6.5 The 1947 Manix, California Earthquake · 22 km NW of this epicentre
  3. 5.8 13km WSW of Ludlow, CA · 19 km SSE of this epicentre
  4. 5.4 21km SW of Ludlow, California · 28 km S of this epicentre
  5. 5.4 32km SSW of Ludlow, California · 45 km SSE 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 34.8287, -116.3805. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
San Bernardino County, CA 18 km (11 mi) E earthquakes near San Bernardino County

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

Aftershocks so far

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

  1. 1.6 40km NE of Big Bear City, CA
  2. 1.7 13km W of Ludlow, CA
  3. 1.8 25km SSW of Ludlow, CA
  4. 1.6 36km ENE of Lucerne Valley, CA
  5. 1.7 39km WSW of Ludlow, CA
  6. 2.3 39km WSW of Ludlow, CA
  7. 3.3 36km N of Yucca Valley, CA
  8. 2.3 24km WSW of Baker, CA
  9. 2.1 24km WSW of Baker, CA
  10. 2.3 37km ENE of Lucerne Valley, CA
  11. 2.1 10km E of Barstow, CA
  12. 1.7 34km N of Yucca Valley, CA
  13. 2.8 36km N of Yucca Valley, CA
  14. 2.5 40km WSW of Ludlow, CA
  15. 2.0 34km N of Yucca Valley, 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.