Earthquake · reviewed by a seismologist
M 4.0mw
12km W of Ludlow, CA
Yes. A magnitude 4.0 earthquake was recorded 12km W of Ludlow, CA, at 8:41 am PST on 7 February 2019 (16:41 UTC), 1.6 km deep. 28 people have reported feeling it to USGS.
- When
- Magnitude
- M 4.0 (mw)
- Depth
- 1.6 km below the surface
- Felt
- 28 reports · strongest reported intensity III
- Measured shaking
- intensity VI (ShakeMap)
- Nearest
- San Bernardino County, 19 km NNE
- Nearest mapped fault
- Pisgah-Bullion fault, 10 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 2563 days ago
Earthquake alerts for Joshua Tree, CA
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Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
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 95 km (59 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 14 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.0 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 12,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 560× the energy of this one
- Magna, Utah 2020 M 5.7 390× the energy of this one
- This earthquake M 4.0 about 14 tons of TNT
- Around the size people start to feel M 3.0 this one released 29× more
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 3.2 times the energy of this one.
Before 2016, the USGS record lists 13 earthquakes of M5 or more within 50 km; the five largest:
- 7.1 The 1999 Hector Mine, California Earthquake · 11 km S of this epicentre
- 6.5 The 1947 Manix, California Earthquake · 38 km NW of this epicentre
- 5.8 13km WSW of Ludlow, CA · 3 km S of this epicentre
- 5.5 17km WSW of Amboy, CA · 41 km ESE of this epicentre
- 5.4 26km NNW of Yucca Valley, CA · 45 km SSW 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 34.7040, -116.2862. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| San Bernardino County, CA | 19 km (12 mi) | NNE | earthquakes near San Bernardino County |
| Riverside County, CA | 111 km (69 mi) | SSE | earthquakes near Riverside County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
59 earthquakes have been recorded within 50 km since this one.
- 1.6 14km WSW of Ludlow, CA
- 1.5 13km WSW of Ludlow, CA
- 2.2 14km WSW of Ludlow, CA
- 1.8 19km NW of Ludlow, CA
- 1.7 11km W of Ludlow, CA
- 1.9 24km W of Ludlow, CA
- 1.6 29km N of Yucca Valley, CA
- 1.5 26km N of Yucca Valley, CA
- 1.8 39km WSW of Ludlow, CA
- 1.5 39km WSW of Ludlow, CA
- 2.1 39km WSW of Ludlow, CA
- 1.9 26km W of Ludlow, CA
- 1.7 32km NW of Ludlow, CA
- 1.6 12km W of Ludlow, CA
- 1.6 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
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.