QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7ml

Earthquake near Piñon Hills, CA

No earthquake was likely felt in Piñon Hills in the 24 hours to 1:38 pm PST (21:38 UTC). The last one was M 1.7, 6 km (4 mi) SSW, at 6:36 pm PDT on 22 October 2026, estimated intensity II (weak) in town. Every earthquake near Piñon Hills

This page: a magnitude 1.7 earthquake was recorded 4 km (3 mi) south-southwest of Piñon Hills, CA, at 5:43 am PDT on 11 October 2020 (12:43 UTC), 5.6 km deep. 4 people have reported feeling it to USGS.

USGS: 4km SSW of Pinon Hills, CA

80 km (50 mi) ENE of Los Angeles, CA · 32 km (20 mi) NNW of Rancho Cucamonga, CA

5:43 am PDT, Oct 11, 2020 · · 5.6 km deep · released about 12 lb of TNT

Every earthquake near Piñon Hills Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Los Angeles County 59 kmOrange County 81 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
5:43 am PDT on 11 October 2020 ()
Where
4 km (3 mi) south-southwest of Piñon Hills, CA · earthquakes near Piñon Hills
Magnitude
M 1.7 (ml)
Depth
5.6 km below the surface
Felt
4 reports · strongest reported intensity II
Nearest
Los Angeles County, 59 km WSW
Nearest mapped fault
San Andreas 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 2222 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 12 km (7 mi) from the epicentre. In Piñon Hills, 4 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: Wrightwood 6 km, intensity II · Phelan 10 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 12 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,200,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 870,000× the energy of this one
  3. Around the size people start to feel M 3.0 78× the energy of this one
  4. This earthquake M 1.7 about 12 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 4.4 on 2018-08-29 — about 9,100 times the energy of this one.

Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:

  1. 5.8 The 1991 Sierra Madre, California Earthquake · 33 km WSW of this epicentre
  2. 5.5 The 1990 Upland, California Earthquake · 29 km S of this epicentre
  3. 5.2 3km W of Lytle Creek, CA · 21 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 34.4015, -117.6715. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Los Angeles County, CA 59 km (37 mi) WSW earthquakes near Los Angeles County
Orange County, CA 81 km (51 mi) S earthquakes near Orange County
Kern County, CA 143 km (89 mi) NW earthquakes near Kern County

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

Aftershocks so far

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

  1. 2.1 5km W of Devore, CA
  2. 2.2 4km ESE of Altadena, CA
  3. 2.8 6km SSW of Pearblossom, CA
  4. 2.4 8km NNW of Fontana, CA
  5. 1.5 5km SSE of Crestline, CA
  6. 1.6 2km NNW of Fontana, CA
  7. 1.6 4km NNW of Fontana, CA
  8. 1.6 6km SSW of Pearblossom, CA
  9. 1.6 2km SE of Muscoy, CA
  10. 2.5 15km WNW of Adelanto, CA
  11. 2.3 4km WNW of Devore, CA
  12. 2.2 4km WNW of Devore, CA
  13. 1.7 7km SSW of Pearblossom, CA
  14. 1.5 6km S of Littlerock, CA
  15. 3.1 7km SSE of Littlerock, 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.