QuakeIndex

Earthquake · reviewed by a seismologist

M 2.6ml

Earthquake near Sierra Madre, CA

No earthquake was likely felt in Sierra Madre in the 24 hours to 4:34 am PST (12:34 UTC). The last one was M 3.8, 70 km (44 mi) WNW, at 8:00 pm PDT on 29 September 2026, estimated intensity II (weak) in town; 199 felt reports to USGS. Every earthquake near Sierra Madre

This page: a magnitude 2.6 earthquake was recorded 6 km (4 mi) northeast of Sierra Madre, CA, at 3:09 pm PDT on 8 June 2023 (22:09 UTC), 15 km deep. 54 people have reported feeling it to USGS.

USGS: 6km NE of Sierra Madre, CA

8 km (5 mi) NNE of Arcadia, CA · 42 km (26 mi) ENE of Los Angeles, CA

3:09 pm PDT, Jun 8, 2023 · · 15 km deep · released about 280 lb of TNT

Every earthquake near Sierra Madre Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Los Angeles County 23 kmOrange County 63 kmVentura County 104 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
3:09 pm PDT on 8 June 2023 ()
Where
6 km (4 mi) northeast of Sierra Madre, CA · earthquakes near Sierra Madre
Magnitude
M 2.6 (ml)
Depth
15 km below the surface
Felt
54 reports · strongest reported intensity IV
Nearest
Los Angeles County, 23 km W
Nearest mapped fault
Sierra Madre fault, 3 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 826 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 19 km (12 mi) from the epicentre. In Sierra Madre, 6 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.

Likely felt in: Sierra Madre 6 km, intensity II · Monrovia 7 km, intensity II · Arcadia 8 km, intensity II · Altadena 11 km, intensity II · Temple City 12 km, intensity II · Azusa 13 km, intensity II · Pasadena 14 km, intensity II · Baldwin Park 14 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 280 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 53,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 38,000× the energy of this one
  3. Around the size people start to feel M 3.0 3.3× the energy of this one
  4. This earthquake M 2.6 about 280 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 680 times the energy of this one.

Before 2016, the USGS record lists 17 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.7 Northridge, California, earthquake · 48 km W of this epicentre
  2. 6.6 1971 San Fernando Earthquake, California · 40 km NW of this epicentre
  3. 5.9 The 1987 Whittier Narrows, California Earthquake · 17 km SSW of this epicentre
  4. 5.9 1km ENE of Granada Hills, California · 45 km W of this epicentre
  5. 5.8 10km SSW of Agua Dulce, CA · 40 km NW 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 34.2057, -118.0143. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Los Angeles County, CA 23 km (14 mi) W earthquakes near Los Angeles County
Orange County, CA 63 km (39 mi) SSE earthquakes near Orange County
Ventura County, CA 104 km (65 mi) W earthquakes near Ventura 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 9 km SW of Lytle Creek, CA
  2. 1.6 2 km NE of Vincent, CA
  3. 1.5 3 km NNE of Baldwin Hills, CA
  4. 2.6 1 km SSE of View Park-Windsor Hills, CA
  5. 1.9 7 km N of Rancho Cucamonga, CA
  6. 1.6 4 km NNE of Baldwin Hills, CA
  7. 2.7 3 km E of Carson, CA
  8. 2.7 4 km ENE of Inglewood, CA
  9. 1.6 5 km NE of View Park-Windsor Hills, CA
  10. 1.7 4 km ESE of Gardena, CA
  11. 2.1 3 km NNE of Granada Hills, CA
  12. 1.7 10 km E of Santa Clarita, CA
  13. 1.7 1 km ENE of Lennox, CA
  14. 1.9 5 km SE of Ontario, CA
  15. 1.8 4km SW of Compton, 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.