Earthquake · reviewed by a seismologist
M 1.6ml
Earthquake near Highland, CA
No earthquake was likely felt in Highland in the 24 hours to 4:52 am PST (12:52 UTC). The last one was M 2.1, 11 km (7 mi) SSW, at 10:40 am PDT on 31 October 2026, estimated intensity II (weak) in town. Every earthquake near Highland
This page: a magnitude 1.6 earthquake was recorded 4 km (3 mi) southwest of Highland, CA, at 10:28 am PDT on 4 September 2021 (17:28 UTC), 9.1 km deep.
USGS: 4km SW of Highland, CA
6 km (4 mi) SE of San Bernardino, CA
- When
- 10:28 am PDT on 4 September 2021 ()
- Where
- 4 km (3 mi) southwest of Highland, CA · earthquakes near Highland
- Magnitude
- M 1.6 (ml)
- Depth
- 9.1 km below the surface
- Felt
- no reports yet
- Nearest
- Orange County, 69 km SW
- Nearest mapped fault
- San Jacinto fault, 4 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 1891 days ago
Earthquake alerts for Highland, CA
Get a notification in this browser when USGS records an earthquake near Highland, 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 7 km (4 mi) from the epicentre. In Highland, 4 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.
Likely felt in: Highland 4 km, intensity II · San Bernardino 4 km, intensity II · Loma Linda 7 km, intensity II. Estimated for each town centre; each link is that town's own record.
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 4.5 on 2018-05-08 — about 21,000 times the energy of this one.
Before 2016, the USGS record lists 20 earthquakes of M5 or more within 50 km; the five largest:
- 6.7 The 1918 San Jacinto, California Earthquake · 46 km SSE of this epicentre
- 6.3 The 1992 Big Bear, California Earthquake · 40 km ENE of this epicentre
- 6.2 3 km SE of San Bernardino, California · 2 km SW of this epicentre
- 6.0 The 1910 Lake Elsinore, California Earthquake · 47 km SSW of this epicentre
- 5.6 7km ENE of Running Springs, CA · 24 km NE 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 34.1052, -117.2425. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Orange County, CA | 69 km (43 mi) | SW | earthquakes near Orange County |
| Los Angeles County, CA | 94 km (59 mi) | W | earthquakes near Los Angeles County |
| Riverside County, CA | 122 km (76 mi) | ESE | earthquakes near Riverside County |
| San Bernardino County, CA | 128 km (80 mi) | NE | earthquakes near San Bernardino 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.
- 1.8 13km SE of Big Bear City, CA
- 1.5 2km E of Yucaipa, CA
- 2.5 6km E of Yucaipa, CA
- 2.2 13km SE of Big Bear City, CA
- 1.7 13km SE of Big Bear City, CA
- 1.5 13km SE of Big Bear City, CA
- 1.5 13km SE of Big Bear City, CA
- 1.6 5km NNE of Fontana, CA
- 2.1 3km SW of San Bernardino, CA
- 1.9 5km WSW of Devore, CA
- 1.6 3km E of Loma Linda, CA
- 2.0 4km SE of Home Gardens, CA
- 1.7 3km WSW of Yucaipa, CA
- 1.9 3km WNW of Fontana, CA
- 1.6 7km NW 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.