QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1ml

Earthquake near Lompoc, CA

No earthquake was likely felt in Lompoc in the 24 hours to 6:12 am PST (14:12 UTC). The last one was M 2.3, 11 km (7 mi) SSW, at 6:34 am PDT on 26 August 2026, estimated intensity II (weak) in town. Every earthquake near Lompoc

This page: a magnitude 2.1 earthquake was recorded 36 km (22 mi) southwest of Lompoc, CA, at 4:40 am PDT on 11 August 2023 (11:40 UTC), 5.9 km deep.

USGS: 36 km SW of Lompoc, CA

64 km (40 mi) SSW of Santa Maria, CA

4:40 am PDT, Aug 11, 2023 · · 5.9 km deep · released about 40 lb of TNT

10 km30 km60 km120 km N Santa Barbara County 66 kmSan Luis Obispo County 112 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
4:40 am PDT on 11 August 2023 ()
Where
36 km (22 mi) southwest of Lompoc, CA · earthquakes near Lompoc
Magnitude
M 2.1 (ml)
Depth
5.9 km below the surface
Felt
no reports yet
Nearest
Santa Barbara County, 66 km ENE
Nearest mapped fault
Pitas Point fault, 21 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 1189 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 16 km (10 mi) from the epicentre. In Lompoc, 36 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.

How big was it?

This earthquake released about 40 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 5.8 380,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 270,000× the energy of this one
  3. Around the size people start to feel M 3.0 24× the energy of this one
  4. This earthquake M 2.1 about 40 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 2017-10-26 — about 2,400 times the energy of this one.

Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:

  1. 6.9 The 1927 Lompoc, California Earthquake · 30 km N 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 34.4133, -120.7388. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Santa Barbara County, CA 66 km (41 mi) ENE earthquakes near Santa Barbara County
San Luis Obispo County, CA 112 km (69 mi) NNE earthquakes near San Luis Obispo County

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

Aftershocks so far

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

  1. 1.9 25 km SSW of Solvang, CA
  2. 2.3 11 km SSW of Lompoc, CA
  3. 1.6 13 km S of Lompoc, CA
  4. 2.2 11 km S of Lompoc, CA
  5. 1.7 12 km S of Lompoc, CA
  6. 1.7 12 km SSW of Lompoc, CA
  7. 2.5 12 km SSW of Lompoc, CA
  8. 2.7 12 km S of Lompoc, CA
  9. 1.9 12 km S of Lompoc, CA
  10. 2.5 12 km SSW of Lompoc, CA
  11. 1.6 12 km SSW of Lompoc, CA
  12. 2.8 12 km SSW of Lompoc, CA
  13. 1.9 13 km SSW of Lompoc, CA
  14. 2.5 13 km SSW of Lompoc, CA
  15. 1.8 26 km W of Lompoc, 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.