Earthquake · reviewed by a seismologist
M 2.3ml
Earthquake near Highland, CA
No earthquake was likely felt in Highland in the 24 hours to 3:43 am PST (11:43 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 2.3 earthquake was recorded 7 km (4 mi) north-northwest of Highland, CA, at 7:05 am PDT on 21 April 2018 (14:05 UTC), 2.5 km deep. 8 people have reported feeling it to USGS.
USGS: 7km NNW of Highland, CA
8 km (5 mi) NE of San Bernardino, CA · 110 km (68 mi) E of Los Angeles, CA
- When
- 7:05 am PDT on 21 April 2018 ()
- Where
- 7 km (4 mi) north-northwest of Highland, CA · earthquakes near Highland
- Magnitude
- M 2.3 (ml)
- Depth
- 2.5 km below the surface
- Felt
- 8 reports · strongest reported intensity III
- Nearest
- Orange County, 76 km SW
- Nearest mapped fault
- San Andreas fault, 3 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 3030 days ago
Earthquake alerts for Highland, CA
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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 19 km (12 mi) from the epicentre. In Highland, 7 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 7 km, intensity II · Lake Arrowhead 8 km, intensity II · San Bernardino 10 km, intensity II · Muscoy 11 km, intensity II · Colton 15 km, intensity II · Redlands 15 km, intensity II · Rialto 16 km, intensity II · Loma Linda 16 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 77 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 200,000× the energy of this one
- Magna, Utah 2020 M 5.7 140,000× the energy of this one
- Around the size people start to feel M 3.0 12× the energy of this one
- This earthquake M 2.3 about 77 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 4.4 on 2016-01-06 — about 1,500 times the energy of this one.
Before 2016, the USGS record lists 15 earthquakes of M5 or more within 50 km; the five largest:
- 6.3 The 1992 Big Bear, California Earthquake · 37 km E of this epicentre
- 6.2 3 km SE of San Bernardino, California · 11 km SSW of this epicentre
- 5.6 7km ENE of Running Springs, CA · 19 km ENE of this epicentre
- 5.5 The 1990 Upland, California Earthquake · 43 km W of this epicentre
- 5.5 11km SSE of Big Bear Lake, California · 35 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 34.1858, -117.2318. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Orange County, CA | 76 km (47 mi) | SW | earthquakes near Orange County |
| Los Angeles County, CA | 95 km (59 mi) | W | earthquakes near Los Angeles County |
| San Bernardino County, CA | 122 km (76 mi) | NE | earthquakes near San Bernardino County |
| Riverside County, CA | 124 km (77 mi) | ESE | 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.
- 2.0 7km NNW of Big Bear Lake, CA
- 1.8 3km W of Cabazon, CA
- 2.2 3km ENE of Calimesa, CA
- 1.8 11km ESE of Running Springs, CA
- 1.7 11km N of Cabazon, CA
- 1.8 6km S of Redlands, CA
- 1.6 6km S of Redlands, CA
- 2.8 4km SE of Loma Linda, CA
- 1.9 11km N of Cabazon, CA
- 1.6 10km N of Cabazon, CA
- 2.6 11km N of Cabazon, CA
- 1.8 12km N of Cabazon, CA
- 1.6 11km N of Cabazon, CA
- 2.4 11km N of Cabazon, CA
- 1.8 11km N of Cabazon, 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.