QuakeIndex

Earthquake · reviewed by a seismologist

M 2.7ml

Earthquake near Alpine, CA

No earthquake was likely felt in Alpine in the 24 hours to 12:34 pm PST (20:34 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 2.7 earthquake was recorded 48 km (30 mi) east-northeast of Alpine, CA, at 11:59 pm PDT on 21 May 2019 (06:59 UTC), 3.8 km deep. 4 people have reported feeling it to USGS.

USGS: 23km SW of Ocotillo Wells, CA

82 km (51 mi) ENE of San Diego, CA

11:59 pm PDT, May 21, 2019 · · 3.8 km deep · released about 290 lb of TNT

Every earthquake near Alpine Felt it? Tell USGS Check my area
10 km30 km60 km120 km N San Diego County 47 kmImperial County 86 kmRiverside County 88 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
11:59 pm PDT on 21 May 2019 ()
Where
48 km (30 mi) east-northeast of Alpine, CA · earthquakes near Alpine
Magnitude
M 2.7 (ml)
Depth
3.8 km below the surface
Felt
4 reports · strongest reported intensity III
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 2690 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 24 km (15 mi) from the epicentre. In Alpine, 48 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: Pine Valley.

How big was it?

This earthquake released about 290 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 51,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 36,000× the energy of this one
  3. Around the size people start to feel M 3.0 3.2× the energy of this one
  4. This earthquake M 2.7 about 290 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 4.0 on 2016-07-31 — about 110 times the energy of this one.

Before 2016, the USGS record lists 16 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.6 The 1942 Fish Creek Mountains, California Earthquake · 46 km E of this epicentre
  2. 6.6 The 1968 Borrego Mountain, California Earthquake · 28 km NE of this epicentre
  3. 6.6 The 1987 Superstition Hills, California Earthquake · 40 km E of this epicentre
  4. 6.4 The 1954 San Jacinto Fault, California Earthquake · 40 km NNE of this epicentre
  5. 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 32.9752, -116.2793. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection 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

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

  1. 3.1 13km ENE of Borrego Springs, CA
  2. 1.6 14km ENE of Borrego Springs, CA
  3. 3.1 12km ENE of Borrego Springs, CA
  4. 1.5 13km ENE of Borrego Springs, CA
  5. 1.6 14km ENE of Borrego Springs, CA
  6. 2.0 17km WNW of Westmorland, CA
  7. 1.9 7km NE of Borrego Springs, CA
  8. 1.9 24km SSW of Ocotillo Wells, CA
  9. 1.9 11km NNE of Borrego Springs, CA
  10. 2.2 25km NW of Ocotillo, CA
  11. 1.6 25km NW of Ocotillo, CA
  12. 2.2 25km NW of Ocotillo, CA
  13. 2.0 17km W of Ocotillo, CA
  14. 2.0 19km ESE of Julian, CA
  15. 2.2 9km SE of Lake Henshaw, 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.