QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1ml

Earthquake near Holtville, CA

No earthquake was likely felt in Holtville in the 24 hours to 10:15 am PST (18:15 UTC). The last one was M 4.9, 46 km (29 mi) SSE, at 10:27 am PST on 3 November 2026, estimated intensity III (weak) in town; 321 felt reports to USGS. Every earthquake near Holtville

This page: a magnitude 2.1 earthquake was recorded 8 km (5 mi) west of Holtville, CA, at 9:37 pm PDT on 21 July 2021 (04:37 UTC), 8.5 km deep.

USGS: 8km W of Holtville, CA

9:37 pm PDT, Jul 21, 2021 · · 8.5 km deep · released about 46 lb of TNT

Every earthquake near Holtville Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Imperial County 28 kmRiverside County 114 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
9:37 pm PDT on 21 July 2021 ()
Where
8 km (5 mi) west of Holtville, CA · earthquakes near Holtville
Magnitude
M 2.1 (ml)
Depth
8.5 km below the surface
Felt
no reports yet
Nearest
Imperial County, 28 km NNE
Nearest mapped fault
Imperial fault, under 1 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 1939 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 15 km (9 mi) from the epicentre. In Holtville, 8 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: Holtville 8 km, intensity II · El Centro 9 km, intensity II · Imperial 11 km, intensity II · Calexico 15 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 46 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 330,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 230,000× the energy of this one
  3. Around the size people start to feel M 3.0 21× the energy of this one
  4. This earthquake M 2.1 about 46 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 5.3 on 2021-06-05 — about 50,000 times the energy of this one.

Before 2016, the USGS record lists 42 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.9 The 1940 Imperial Valley, California Earthquake · 9 km ENE of this epicentre
  2. 6.6 The 1942 Fish Creek Mountains, California Earthquake · 35 km WNW of this epicentre
  3. 6.6 The 1987 Superstition Hills, California Earthquake · 43 km WNW of this epicentre
  4. 6.4 The 1979 Imperial Valley Earthquake, California-Baja California · 19 km SSE of this epicentre
  5. 6.3 The 1906 Imperial Valley, California Earthquake · 11 km NNW 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 32.8090, -115.4643. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Imperial County, CA 28 km (17 mi) NNE earthquakes near Imperial County
Riverside County, CA 114 km (71 mi) NNW earthquakes near Riverside County

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

Aftershocks so far

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

  1. 1.9 27km WSW of Westmorland, CA
  2. 2.1 27km SE of Ocotillo Wells, CA
  3. 2.2 14km N of Ocotillo, CA
  4. 2.2 14km N of Ocotillo, CA
  5. 1.8 8km W of Progreso, B.C., MX
  6. 1.8 11km W of Calipatria, CA
  7. 2.0 10km WSW of Niland, CA
  8. 2.9 19km N of Ocotillo, CA
  9. 1.8 8km W of Progreso, B.C., MX
  10. 1.9 9km W of Calipatria, CA
  11. 1.6 7km SW of Niland, CA
  12. 1.8 9km SW of Niland, CA
  13. 1.9 15km WNW of Progreso, B.C., MX
  14. 1.9 8km SSW of Progreso, B.C., MX
  15. 1.6 9km SW of Niland, 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.