QuakeIndex

Earthquake · reviewed by a seismologist

M 3.5mw

Earthquake near Aguanga, CA

No earthquake was likely felt in Aguanga in the 24 hours to 1:24 pm PST (21:24 UTC). The last one was M 2.6, 20 km (12 mi) ESE, at 10:44 pm PST on 5 November 2026, estimated intensity II (weak) in town; 7 felt reports to USGS. Every earthquake near Aguanga

This page: a magnitude 3.5 earthquake was recorded 7 km (4 mi) west-southwest of Aguanga, CA, at 9:41 pm PST on 4 December 2020 (05:41 UTC), 8.1 km deep. 743 people have reported feeling it to USGS.

USGS: 7km WSW of Aguanga, CA

70 km (44 mi) NNE of San Diego, CA · 20 km (13 mi) ESE of Temecula, CA

9:41 pm PST, Dec 4, 2020 · · 8.1 km deep · released about 3.2 tons of TNT

Every earthquake near Aguanga Felt it? Tell USGS Check my area
10 km30 km60 km120 km N San Diego County 47 kmOrange County 83 kmRiverside County 93 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
9:41 pm PST on 4 December 2020 ()
Where
7 km (4 mi) west-southwest of Aguanga, CA · earthquakes near Aguanga
Magnitude
M 3.5 (mw)
Depth
8.1 km below the surface
Felt
743 reports · strongest reported intensity IV
Measured shaking
intensity V (ShakeMap)
Nearest
San Diego County, 47 km SSE
Nearest mapped fault
Elsinore fault, 2 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 1610 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 66 km (41 mi) from the epicentre. In Aguanga, 7 km away, the estimate is intensity III (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: Aguanga 7 km, intensity III · Temecula 22 km, intensity III · Anza 28 km, intensity II · Murrieta 30 km, intensity II · Valle Vista 36 km, intensity II · Hemet 37 km, intensity II · Escondido 37 km, intensity II · Wildomar 38 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 3.2 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.5 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 53,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 2,400× the energy of this one
  3. Magna, Utah 2020 M 5.7 1,700× the energy of this one
  4. This earthquake M 3.5 about 3.2 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 6.7× more

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 2016-06-10 — about 290 times the energy of this one.

Before 2016, the USGS record lists 8 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.7 The 1918 San Jacinto, California Earthquake · 38 km N of this epicentre
  2. 5.4 20km NNW of Borrego Springs, CA · 42 km E of this epicentre
  3. 5.3 6km SSE of Hemet, CA · 31 km N of this epicentre
  4. 5.3 18km ESE of Anza, CA · 40 km E of this epicentre
  5. 5.2 10km ESE of Anza, 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 33.4212, -116.9312. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
San Diego County, CA 47 km (29 mi) SSE earthquakes near San Diego County
Orange County, CA 83 km (52 mi) WNW earthquakes near Orange County
Riverside County, CA 93 km (58 mi) ENE earthquakes near Riverside County

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

Aftershocks so far

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

  1. 2.4 14km WNW of Anza, CA
  2. 2.4 7km SSW of Idyllwild, CA
  3. 2.3 6km SW of Idyllwild, CA
  4. 2.1 20km ESE of Anza, CA
  5. 2.0 20km ESE of Anza, CA
  6. 1.6 22km ESE of Anza, CA
  7. 1.5 6km ENE of Anza, CA
  8. 1.8 6km W of Palomar Observatory, CA
  9. 1.6 8km NE of Aguanga, CA
  10. 2.3 6km N of Lake Henshaw, CA
  11. 1.8 9km NE of Aguanga, CA
  12. 1.8 6km SW of Idyllwild, CA
  13. 2.2 16km NNW of Borrego Springs, CA
  14. 2.0 13km WNW of Anza, CA
  15. 2.1 20km ESE of Anza, 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.