quarry blast · reviewed by a seismologist
M 1.6ml
Earthquake near Apple Valley, CA
No earthquake was likely felt in Apple Valley in the 24 hours to 5:09 am PST (13:09 UTC). The last one was M 4.3, 107 km (66 mi) NNW, at 9:40 am PDT on 13 July 2026, estimated intensity II (weak) in town; 1,090 felt reports to USGS. Every earthquake near Apple Valley
No: USGS classifies this as a quarry blast, not an earthquake. A magnitude 1.6 quarry blast was recorded 15 km (10 mi) north-northeast of Apple Valley, CA, at 4:09 pm PDT on 21 September 2017 (23:09 UTC), less than 1 km deep.
USGS: 15km NNE of Apple Valley, CA
13 km (8 mi) NE of Apple Valley, CA · 137 km (85 mi) ENE of Los Angeles, CA
- When
- 4:09 pm PDT on 21 September 2017 ()
- Where
- 15 km (10 mi) north-northeast of Apple Valley, CA · earthquakes near Apple Valley
- Magnitude
- M 1.6 (ml)
- Depth
- -1.3 km below the surface
- Felt
- no reports yet
- Nearest
- San Bernardino County, 89 km ENE
- Nearest mapped fault
- Helendale-South Lockhart fault, 2 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 3304 days ago
Earthquake alerts for Apple Valley, CA
Get a notification in this browser when USGS records an earthquake near Apple Valley, CA. No account or email needed.
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 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 11 km (7 mi) from the epicentre. In Apple Valley, 15 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: Victorville, Spring Valley Lake, Lucerne Valley, Silver Lakes, Adelanto, Barstow Heights.
USGS catalogues this as quarry blast, not an earthquake.
How big was it?
This earthquake released about 7.8 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 1,900,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,400,000× the energy of this one
- Around the size people start to feel M 3.0 120× the energy of this one
- This earthquake M 1.6 about 7.8 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 11,000 times the energy of this one.
Before 2016, the USGS record lists 7 earthquakes of M5 or more within 50 km; the five largest:
- 5.6 7km ENE of Running Springs, CA · 43 km S of this epicentre
- 5.3 Near San Bernardino, California · 47 km S of this epicentre
- 5.3 6km WNW of Big Bear Lake, CA · 42 km SSE of this epicentre
- 5.3 1km N of Big Bear Lake, California · 45 km SSE of this epicentre
- 5.3 10km NNW of Big Bear City, California · 37 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 34.6257, -117.1157. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| San Bernardino County, CA | 89 km (55 mi) | ENE | earthquakes near San Bernardino County |
| Los Angeles County, CA | 115 km (72 mi) | WSW | earthquakes near Los Angeles County |
| Orange County, CA | 122 km (76 mi) | SSW | earthquakes near Orange County |
| Riverside County, CA | 143 km (89 mi) | SE | earthquakes near Riverside County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
38 earthquakes have been recorded within 50 km since this one.
- 1.5 9km NE of Big Bear City, CA
- 1.9 11km SSE of Lucerne Valley, CA
- 2.6 7km NW of Big Bear Lake, CA
- 1.7 8km N of Big Bear City, CA
- 1.8 9km NNW of Big Bear Lake, CA
- 2.3 16km NNE of Lucerne Valley, CA
- 1.6 11km NE of Big Bear City, CA
- 1.5 9km N of Big Bear City, CA
- 2.2 10km E of Running Springs, CA
- 1.8 3km WSW of Big Bear City, CA
- 2.0 19km NE of Big Bear City, CA
- 1.8 11km NE of Running Springs, CA
- 1.6 11km SE of Lucerne Valley, CA
- 2.1 11km N of Big Bear Lake, CA
- 1.5 3km WSW of Big Bear City, 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.