QuakeIndex

Earthquake · reviewed by a seismologist

M 2.5ml

7km W of San Clemente Is. (SE tip), CA

Yes. A magnitude 2.5 earthquake was recorded 7km W of San Clemente Is. (SE tip), CA, at 6:07 am PST on 18 November 2021 (14:07 UTC), 3.9 km deep. 1 person has reported feeling it to USGS.

· 3.9 km deep · released about 160 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Orange County 111 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
Magnitude
M 2.5 (ml)
Depth
3.9 km below the surface
Felt
1 report · strongest reported intensity I
Nearest
Orange County, 111 km NNE
Nearest mapped fault
San Clemente fault, 6 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 1755 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 21 km (13 mi) from the epicentre. 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 160 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 95,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 68,000× the energy of this one
  3. Around the size people start to feel M 3.0 6× the energy of this one
  4. This earthquake M 2.5 about 160 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 4.3 on 2019-06-05 — about 540 times the energy of this one.

Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:

  1. 5.8 11km NNE of San Clemente Is. (SE tip), CA · 14 km NE of this epicentre
  2. 5.2 42km SSW of San Clemente Is. (SE tip), CA · 40 km SSW 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 32.8300, -118.4213. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Orange County, CA 111 km (69 mi) NNE earthquakes near Orange County

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

Aftershocks so far

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

  1. 2.5 12 km SSE of San Clemente Is. (SE tip), CA
  2. 1.7 40 km ENE of San Clemente Is. (SE tip), CA
  3. 1.9 33 km ENE of San Clemente Is. (SE tip), CA
  4. 2.4 33 km ENE of San Clemente Is. (SE tip), CA
  5. 2.5 32 km ENE of San Clemente Is. (SE tip), CA
  6. 2.9 10 km WNW of San Clemente Is. (SE tip), CA
  7. 1.9 27 km NE of San Clemente Is. (SE tip), CA
  8. 2.6 25 km ESE of San Clemente Is. (SE tip), CA
  9. 1.8 37 km SE of San Clemente Is. (SE tip), CA
  10. 2.6 6 km SE of San Clemente Is. (SE tip), CA
  11. 3.0 25 km SE of San Clemente Is. (SE tip), CA
  12. 2.7 42 km NE of San Clemente Is. (SE tip), CA
  13. 2.3 6 km SSE of San Clemente Is. (SE tip), CA
  14. 3.0 8 km SSE of San Clemente Is. (SE tip), CA
  15. 2.0 41 km NE of San Clemente Is. (SE tip), 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.