Earthquake · reviewed by a seismologist
M 1.6ml
Earthquake near Alpine, CA
No earthquake was likely felt in Alpine in the 24 hours to 11:47 am PST (19:47 UTC). The last one was M 4.9, 155 km (96 mi) ESE, at 10:27 am PST on 3 November 2026, estimated intensity II (weak) in town; 321 felt reports to USGS. Every earthquake near Alpine
This page: a magnitude 1.6 earthquake was recorded 48 km (30 mi) east-northeast of Alpine, CA, at 6:30 pm PDT on 28 May 2025 (01:30 UTC), 9.5 km deep.
USGS: 23 km SW of Ocotillo Wells, CA
82 km (51 mi) ENE of San Diego, CA
- When
- 6:30 pm PDT on 28 May 2025 ()
- Where
- 48 km (30 mi) east-northeast of Alpine, CA · earthquakes near Alpine
- Magnitude
- M 1.6 (ml)
- Depth
- 9.5 km below the surface
- Felt
- no reports yet
- Nearest
- San Diego County, 47 km W
- Nearest mapped fault
- Elsinore fault, 8 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 532 days ago
Earthquake alerts for Alpine, CA
Get a notification in this browser when USGS records an earthquake near Alpine, 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 5 km (3 mi) from the epicentre. In Alpine, 48 km away, the estimate is intensity I (not felt). 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: Pine Valley.
How big was it?
This earthquake released about 6.8 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 2,200,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,600,000× the energy of this one
- Around the size people start to feel M 3.0 140× the energy of this one
- This earthquake M 1.6 about 6.8 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 5.2 on 2025-04-14 — about 290,000 times the energy of this one.
Before 2016, the USGS record lists 16 earthquakes of M5 or more within 50 km; the five largest:
- 6.6 The 1942 Fish Creek Mountains, California Earthquake · 46 km E of this epicentre
- 6.6 The 1968 Borrego Mountain, California Earthquake · 28 km NE of this epicentre
- 6.6 The 1987 Superstition Hills, California Earthquake · 40 km E of this epicentre
- 6.4 The 1954 San Jacinto Fault, California Earthquake · 40 km NNE of this epicentre
- 6.2 The 1987 Elmore Ranch, California Earthquake · 47 km ENE 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 32.9743, -116.2782. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| San Diego County, CA | 47 km (29 mi) | W | earthquakes near San Diego County |
| Imperial County, CA | 86 km (54 mi) | E | earthquakes near Imperial County |
| Riverside County, CA | 88 km (55 mi) | NNE | earthquakes near Riverside County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
47 earthquakes have been recorded within 50 km since this one.
- 1.5 13 km ENE of Borrego Springs, CA
- 1.9 18 km N of Ocotillo Wells, CA
- 1.6 16 km ESE of Julian, CA
- 1.5 16 km ESE of Julian, CA
- 1.9 10 km ENE of Ocotillo Wells, CA
- 1.6 5 km W of Borrego Springs, CA
- 1.7 8 km S of Ocotillo, CA
- 2.0 8 km ENE of Julian, CA
- 1.8 1 km SW of Borrego Springs, CA
- 2.0 4 km S of Julian, CA
- 1.8 11 km NNE of Ocotillo Wells, CA
- 1.7 11 km SW of Salton City, CA
- 1.8 11 km SW of Salton City, CA
- 1.8 23 km SW of Ocotillo Wells, CA
- 2.6 17 km ENE of Ocotillo, 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.