QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6ml

Earthquake near Borrego Springs, CA

No earthquake was likely felt in Borrego Springs in the 24 hours to 6:56 am PST (14:56 UTC). The last one was M 4.9, 145 km (90 mi) SE, at 10:27 am PST on 3 November 2026, estimated intensity II (weak) in town; 321 felt reports to USGS. Every earthquake near Borrego Springs

This page: a magnitude 1.6 earthquake was recorded 38 km (24 mi) south-southeast of Borrego Springs, CA, at 10:24 am PDT on 9 October 2021 (17:24 UTC), 10 km deep.

USGS: 24km SSW of Ocotillo Wells, CA

87 km (54 mi) E of San Diego, CA

10:24 am PDT, Oct 9, 2021 · · 10 km deep · released about 6.6 lb of TNT

Every earthquake near Borrego Springs Felt it? Tell USGS Check my area
10 km30 km60 km120 km N San Diego County 53 kmImperial County 81 kmRiverside County 90 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
10:24 am PDT on 9 October 2021 ()
Where
38 km (24 mi) south-southeast of Borrego Springs, CA · earthquakes near Borrego Springs
Magnitude
M 1.6 (ml)
Depth
10 km below the surface
Felt
no reports yet
Nearest
San Diego County, 53 km W
Nearest mapped fault
Elsinore fault, 13 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 1858 days ago

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 4 km (2 mi) from the epicentre. In Borrego Springs, 38 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.

How big was it?

This earthquake released about 6.6 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.

  1. Mineral, Virginia 2011 M 5.8 2,300,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,600,000× the energy of this one
  3. Around the size people start to feel M 3.0 140× the energy of this one
  4. This earthquake M 1.6 about 6.6 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 2020-05-10 — about 30,000 times the energy of this one.

Before 2016, the USGS record lists 15 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.6 The 1942 Fish Creek Mountains, California Earthquake · 41 km E of this epicentre
  2. 6.6 The 1968 Borrego Mountain, California Earthquake · 29 km NNE of this epicentre
  3. 6.6 The 1987 Superstition Hills, California Earthquake · 35 km ENE of this epicentre
  4. 6.4 The 1954 San Jacinto Fault, California Earthquake · 42 km NNE of this epicentre
  5. 6.2 The 1987 Elmore Ranch, California Earthquake · 43 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 32.9390, -116.2182. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
San Diego County, CA 53 km (33 mi) W earthquakes near San Diego County
Imperial County, CA 81 km (50 mi) E earthquakes near Imperial County
Riverside County, CA 90 km (56 mi) NNE earthquakes near Riverside 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. 1.6 12km NE of Ocotillo Wells, CA
  2. 1.5 6km E of Ocotillo Wells, CA
  3. 1.7 16km E of Ocotillo Wells, CA
  4. 1.9 17km ESE of Julian, CA
  5. 2.2 10km N of Borrego Springs, CA
  6. 1.5 11km SSW of Borrego Springs, CA
  7. 2.1 11km SSW of Borrego Springs, CA
  8. 1.6 12km SSW of Borrego Springs, CA
  9. 2.9 19km W of Westmorland, CA
  10. 2.5 11km ENE of Borrego Springs, CA
  11. 1.9 12km ENE of Borrego Springs, CA
  12. 1.9 26km SSW of Ocotillo Wells, CA
  13. 1.8 11km ENE of Borrego Springs, CA
  14. 2.5 11km E of Borrego Springs, CA
  15. 1.8 19km ESE 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

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