QuakeIndex

Earthquake · reviewed by a seismologist

M 1.9ml

Earthquake near Alpine, CA

No earthquake was likely felt in Alpine in the 24 hours to 6:59 am PST (14:59 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 1.9 earthquake was recorded 10 km (6 mi) east-southeast of Alpine, CA, at 2:44 am PDT on 1 May 2024 (09:44 UTC), 15 km deep.

USGS: 10 km ESE of Alpine, CA

44 km (28 mi) E of San Diego, CA · 28 km (17 mi) E of El Cajon, CA

2:44 am PDT, May 1, 2024 · · 15 km deep · released about 20 lb of TNT

10 km30 km60 km120 km N San Diego County 26 kmRiverside County 119 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
2:44 am PDT on 1 May 2024 ()
Where
10 km (6 mi) east-southeast of Alpine, CA · earthquakes near Alpine
Magnitude
M 1.9 (ml)
Depth
15 km below the surface
Felt
no reports yet
Nearest
San Diego County, 26 km NNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 925 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth it was probably too small to be felt, even directly above it. In Alpine, 10 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: Descanso, Pine Valley, Harbison Canyon, Crest, Granite Hills, Jamul.

How big was it?

This earthquake released about 20 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 760,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 540,000× the energy of this one
  3. Around the size people start to feel M 3.0 48× the energy of this one
  4. This earthquake M 1.9 about 20 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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:

  1. 5.2 21km NW of Ocotillo, CA · 48 km E of this epicentre
  2. 5.0 16 km NW of Julian, California · 43 km N of this epicentre
  3. 5.0 26km NE of Pine Valley, CA · 36 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 32.8148, -116.6603. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
San Diego County, CA 26 km (16 mi) NNW earthquakes near San Diego County
Riverside County, CA 119 km (74 mi) NNE earthquakes near Riverside County
Orange County, CA 141 km (88 mi) NW earthquakes near Orange County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

52 earthquakes have been recorded within 50 km since this one.

  1. 2.8 25 km SW of Ocotillo Wells, CA
  2. 2.1 19 km SE of Julian, CA
  3. 1.5 24 km SW of Ocotillo Wells, CA
  4. 1.7 25 km SW of Ocotillo Wells, CA
  5. 1.7 8 km NW of Julian, CA
  6. 1.7 4 km ENE of Rancho San Diego, CA
  7. 2.3 8 km NNW of Julian, CA
  8. 2.0 18 km ESE of Julian, CA
  9. 2.0 18 km ESE of Julian, CA
  10. 1.8 25 km SW of Ocotillo Wells, CA
  11. 2.2 18 km ESE of Julian, CA
  12. 1.5 23 km SW of Ocotillo Wells, CA
  13. 1.9 8 km ESE of Tijuana, B.C., MX
  14. 1.6 11 km NE of Julian, CA
  15. 1.7 25 km SW of Ocotillo Wells, 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

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.