QuakeIndex

Earthquake · reviewed by a seismologist

M 1.5ml

Earthquake near Twentynine Palms, CA

No earthquake was likely felt in Twentynine Palms in the 24 hours to 1:58 pm PST (21:58 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 1.5 earthquake was recorded 10 km (6 mi) south-southeast of Twentynine Palms, CA, at 8:25 am PST on 21 December 2018 (16:25 UTC), 8.0 km deep.

USGS: 11km SSE of Twentynine Palms, CA

41 km (25 mi) NNE of Indio, CA · 127 km (79 mi) E of Riverside, CA

8:25 am PST, Dec 21, 2018 · · 8.0 km deep · released about 6.2 lb of TNT

10 km30 km60 km120 km N Riverside County 36 kmSan Bernardino County 91 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
8:25 am PST on 21 December 2018 ()
Where
10 km (6 mi) south-southeast of Twentynine Palms, CA · earthquakes near Twentynine Palms
Magnitude
M 1.5 (ml)
Depth
8.0 km below the surface
Felt
no reports yet
Nearest
Riverside County, 36 km S
Nearest mapped fault
Pinto Mountain fault (includes Morongo Valley fault), 7 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 2883 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 7 km (4 mi) from the epicentre. In Twentynine Palms, 10 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: Joshua Tree.

How big was it?

This earthquake released about 6.2 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 2,500,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,700,000× the energy of this one
  3. Around the size people start to feel M 3.0 150× the energy of this one
  4. This earthquake M 1.5 about 6.2 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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record lists 22 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.3 The 1992 Landers, California Earthquake · 42 km WNW of this epicentre
  2. 6.1 The 1992 Joshua Tree, California Earthquake · 29 km WSW of this epicentre
  3. 6.0 The 1948 Desert Hot Springs, California Earthquake · 29 km WSW of this epicentre
  4. 5.8 3km NE of Yucca Valley, California · 37 km WNW of this epicentre
  5. 5.7 38km ESE of Twentynine Palms, CA · 31 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 34.0505, -116.0217. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Riverside County, CA 36 km (22 mi) S earthquakes near Riverside County
San Bernardino County, CA 91 km (56 mi) N earthquakes near San Bernardino County
Imperial County, CA 128 km (80 mi) SSE earthquakes near Imperial County
San Diego County, CA 134 km (83 mi) SSW earthquakes near San Diego County

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

Aftershocks so far

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

  1. 1.9 8km SSE of Yucca Valley, CA
  2. 1.5 8km SSE of Yucca Valley, CA
  3. 2.4 33km SE of Twentynine Palms, CA
  4. 1.9 12km NE of Indio, CA
  5. 1.8 16km NE of Indio, CA
  6. 1.7 16km S of Twentynine Palms, CA
  7. 2.3 5km NNE of Yucca Valley, CA
  8. 1.6 12km NNE of Thousand Palms, CA
  9. 2.3 15km S of Twentynine Palms, CA
  10. 2.2 16km S of Twentynine Palms, CA
  11. 2.0 16km NE of Coachella, CA
  12. 1.9 14km NE of Thousand Palms, CA
  13. 1.6 16km S of Twentynine Palms, CA
  14. 1.6 16km S of Twentynine Palms, CA
  15. 1.5 19km ENE of Thousand Palms, 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.