QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

Earthquake near Fountain Valley, CA

No earthquake was likely felt in Fountain Valley in the 24 hours to 4:44 pm PST (00:44 UTC). The last one was M 3.2, 23 km (14 mi) WNW, at 12:44 am PDT on 9 October 2026, estimated intensity II (weak) in town; 1,090 felt reports to USGS. Every earthquake near Fountain Valley

This page: a magnitude 1.8 earthquake was recorded 3 km (2 mi) east-southeast of Fountain Valley, CA, at 3:58 am PDT on 11 May 2023 (10:58 UTC), 15 km deep. 1 person has reported feeling it to USGS.

USGS: 3km ESE of Fountain Valley, CA

in Fountain Valley, CA · 57 km (36 mi) SE of Los Angeles, CA

3:58 am PDT, May 11, 2023 · · 15 km deep · released about 14 lb of TNT

Every earthquake near Fountain Valley Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Orange County 14 kmLos Angeles County 63 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
3:58 am PDT on 11 May 2023 ()
Where
3 km (2 mi) east-southeast of Fountain Valley, CA · earthquakes near Fountain Valley
Magnitude
M 1.8 (ml)
Depth
15 km below the surface
Felt
1 report · strongest reported intensity II
Nearest
Orange County, 14 km ESE
Nearest mapped fault
San Joaquin Hills thrust, 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 1281 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth it was probably too small to be felt, even directly above it. In Fountain Valley, 3 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.

Earthquakes near other towns within 30 km: Costa Mesa, Santa Ana, Garden Grove, Huntington Beach, Newport Beach, Irvine.

How big was it?

This earthquake released about 14 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 760,000× the energy of this one
  3. Around the size people start to feel M 3.0 68× the energy of this one
  4. This earthquake M 1.8 about 14 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 2020-09-19 — about 14,000 times the energy of this one.

Before 2016, the USGS record lists 13 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.4 The 1933 Long Beach, California Earthquake · 10 km SW of this epicentre
  2. 6.0 The 1910 Lake Elsinore, California Earthquake · 48 km E of this epicentre
  3. 5.9 The 1987 Whittier Narrows, California Earthquake · 43 km NNW of this epicentre
  4. 5.4 5km S of Chino Hills, CA · 31 km NNE of this epicentre
  5. 5.3 7km W of Newport Beach, CA · 11 km SW 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 33.7010, -117.9230. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Orange County, CA 14 km (9 mi) ESE earthquakes near Orange County
Los Angeles County, CA 63 km (39 mi) NNW earthquakes near Los Angeles County
San Diego County, CA 130 km (81 mi) SE earthquakes near San Diego County
Ventura County, CA 133 km (83 mi) WNW earthquakes near Ventura 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. 2.7 3 km E of Carson, CA
  2. 2.7 4 km ENE of Inglewood, CA
  3. 1.6 5 km SSE of Home Gardens, CA
  4. 2.2 20 km E of Avalon, CA
  5. 2.3 22 km E of Avalon, CA
  6. 1.5 2 km ESE of Home Gardens, CA
  7. 1.7 4 km ESE of Gardena, CA
  8. 1.8 4 km SE of Home Gardens, CA
  9. 1.7 1 km ENE of Lennox, CA
  10. 1.9 5 km SE of Ontario, CA
  11. 1.6 5km SSE of Home Gardens, CA
  12. 1.8 4km SW of Compton, CA
  13. 1.5 4km SSE of Home Gardens, CA
  14. 1.8 4km SSE of Highland Park, CA
  15. 1.7 5km ESE of Ontario, 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.