QuakeIndex

Earthquake · reviewed by a seismologist

M 1.9ml

Earthquake near Avalon, CA

USGS: 43km SE of Avalon, CA

55 km (34 mi) SW of San Clemente, CA · 112 km (69 mi) SSE of Los Angeles, CA

1:07 pm PDT, Oct 4, 2018 · · 4.8 km deep · released about 22 lb of TNT

Every earthquake near Avalon Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Orange County 70 kmSan Diego 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
1:07 pm PDT on 4 October 2018 ()
Where
43 km (27 mi) SE of Avalon, CA · earthquakes near Avalon
Magnitude
M 1.9 (ml)
Depth
4.8 km below the surface
Felt
1 report · strongest reported intensity II
Nearest
Orange County, 70 km NNE
Nearest mapped fault
San Diego Trough fault, 5 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 2901 days ago

A magnitude 1.9 earthquake was recorded 43 km (27 mi) SE of Avalon, CA, at 1:07 pm PDT on 4 October 2018 (20:07 UTC). 1 person has reported feeling it to USGS. This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

How big was it?

This earthquake released about 22 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 680,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 480,000× the energy of this one
  3. Around the size people start to feel M 3.0 43× the energy of this one
  4. This earthquake M 1.9 about 22 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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

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 · 34 km WSW of this epicentre
  2. 5.5 The 1986 Oceanside, California Earthquake · 16 km SE 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 33.0748, -117.9978. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Orange County, CA 70 km (43 mi) NNE earthquakes near Orange County
San Diego County, CA 114 km (71 mi) E earthquakes near San Diego County

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

Aftershocks so far

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

  1. 1.8 32km WSW of Encinitas, CA
  2. 1.6 31km W of La Jolla, CA
  3. 1.8 39km WSW of Carlsbad, CA
  4. 2.3 23km SW of Laguna Beach, CA
  5. 1.7 24km SW of Laguna Beach, CA
  6. 1.9 23km SSW of Newport Beach, CA
  7. 1.5 23km SSW of Newport Beach, CA
  8. 1.8 22km SW of Laguna Beach, CA
  9. 1.6 23km SW of Laguna Beach, CA
  10. 2.3 24km SW of Laguna Beach, CA
  11. 1.8 22km SSW of Newport Beach, CA
  12. 1.8 48km SSW of San Clemente, CA
  13. 1.7 17km SW of Dana Point, CA
  14. 2.7 16km W of Camp Pendleton South, CA
  15. 2.3 32km W of La Jolla, 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.