QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

Earthquake near Twentynine Palms, CA

No earthquake was likely felt in Twentynine Palms in the 24 hours to 4:02 am PST (12:02 UTC). The last one was M 3.2, 30 km (19 mi) SW, at 9:51 am PDT on 1 August 2026, estimated intensity II (weak) in town; 46 felt reports to USGS. Every earthquake near Twentynine Palms

This page: a magnitude 1.8 earthquake was recorded 48 km (30 mi) north-northwest of Twentynine Palms, CA, at 1:54 pm PDT on 21 August 2018 (20:54 UTC), 2.1 km deep.

USGS: 24km SSW of Ludlow, CA

1:54 pm PDT, Aug 21, 2018 · · 2.1 km deep · released about 17 lb of TNT

Every earthquake near Twentynine Palms Felt it? Tell USGS Check my area
10 km30 km60 km120 km N San Bernardino County 38 kmRiverside County 92 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
1:54 pm PDT on 21 August 2018 ()
Where
48 km (30 mi) north-northwest of Twentynine Palms, CA · earthquakes near Twentynine Palms
Magnitude
M 1.8 (ml)
Depth
2.1 km below the surface
Felt
no reports yet
Nearest
San Bernardino County, 38 km NNE
Nearest mapped fault
Lavic Lake 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 3005 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 14 km (9 mi) from the epicentre. In Twentynine Palms, 48 km away, the estimate is intensity I (not felt). 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 17 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 900,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 640,000× the energy of this one
  3. Around the size people start to feel M 3.0 57× the energy of this one
  4. This earthquake M 1.8 about 17 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 5,200 times the energy of this one.

Before 2016, the USGS record lists 21 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.3 The 1992 Landers, California Earthquake · 40 km SSW of this epicentre
  2. 7.1 The 1999 Hector Mine, California Earthquake · 9 km N of this epicentre
  3. 5.8 3km NE of Yucca Valley, California · 46 km SSW of this epicentre
  4. 5.8 13km WSW of Ludlow, CA · 17 km N of this epicentre
  5. 5.7 2km SSW of Joshua Tree, California · 45 km S 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 34.5262, -116.2647. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
San Bernardino County, CA 38 km (23 mi) NNE earthquakes near San Bernardino County
Riverside County, CA 92 km (57 mi) SSE earthquakes near Riverside County

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

Aftershocks so far

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

  1. 1.7 12km W of Ludlow, CA
  2. 1.9 12km W of Ludlow, CA
  3. 1.8 11km W of Ludlow, CA
  4. 1.6 12km W of Ludlow, CA
  5. 1.7 12km W of Ludlow, CA
  6. 2.1 12km WSW of Ludlow, CA
  7. 1.7 12km W of Ludlow, CA
  8. 1.7 12km W of Ludlow, CA
  9. 1.6 12km W of Ludlow, CA
  10. 2.0 11km W of Ludlow, CA
  11. 2.4 12km W of Ludlow, CA
  12. 2.2 12km W of Ludlow, CA
  13. 2.0 12km W of Ludlow, CA
  14. 2.7 12km W of Ludlow, CA
  15. 1.9 12km W of Ludlow, 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.