QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6ml

Earthquake near Muscoy, CA

No earthquake was likely felt in Muscoy in the 24 hours to 5:08 am PST (13:08 UTC). The last one was M 2.2, 17 km (10 mi) SE, at 8:15 pm PDT on 29 October 2026, estimated intensity II (weak) in town; 1 felt report to USGS. Every earthquake near Muscoy

This page: a magnitude 1.6 earthquake was recorded in Muscoy, CA, at 4:05 am PST on 14 December 2020 (12:05 UTC), 7.4 km deep. 2 people have reported feeling it to USGS.

USGS: 2km SE of Muscoy, CA

in San Bernardino, CA

4:05 am PST, Dec 14, 2020 · · 7.4 km deep · released about 7.3 lb of TNT

Every earthquake near Muscoy Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Orange County 66 kmLos Angeles County 86 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
4:05 am PST on 14 December 2020 ()
Where
in Muscoy, CA · earthquakes near Muscoy
Magnitude
M 1.6 (ml)
Depth
7.4 km below the surface
Felt
2 reports · strongest reported intensity III
Nearest
Orange County, 66 km SW
Nearest mapped fault
San Jacinto fault, 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 2158 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 8 km (5 mi) from the epicentre. 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: Muscoy in town, intensity II · San Bernardino 5 km, intensity II · Rialto 6 km, intensity II · Colton 8 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 7.3 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,500,000× the energy of this one
  3. Around the size people start to feel M 3.0 130× the energy of this one
  4. This earthquake M 1.6 about 7.3 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 2016-01-06 — about 16,000 times the energy of this one.

Before 2016, the USGS record lists 19 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.3 The 1992 Big Bear, California Earthquake · 47 km E of this epicentre
  2. 6.2 3 km SE of San Bernardino, California · 9 km SE of this epicentre
  3. 6.0 The 1910 Lake Elsinore, California Earthquake · 50 km S of this epicentre
  4. 5.6 7km ENE of Running Springs, CA · 29 km ENE of this epicentre
  5. 5.5 The 1990 Upland, California Earthquake · 34 km W 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 34.1433, -117.3302. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Orange County, CA 66 km (41 mi) SW earthquakes near Orange County
Los Angeles County, CA 86 km (53 mi) W earthquakes near Los Angeles County
San Bernardino County, CA 132 km (82 mi) NE earthquakes near San Bernardino County

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

Aftershocks so far

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

  1. 1.8 4km SE of Home Gardens, CA
  2. 1.6 11km WNW of Corona, CA
  3. 1.9 8km SSE of Redlands, CA
  4. 1.8 4km SE of Home Gardens, CA
  5. 1.6 7km NNE of Moreno Valley, CA
  6. 1.8 14km S of Big Bear Lake, CA
  7. 1.9 2km SE of Home Gardens, CA
  8. 1.6 6km NE of Moreno Valley, CA
  9. 1.5 7km ENE of Running Springs, CA
  10. 2.2 14km NNE of Glendora, CA
  11. 1.7 3km W of Calimesa, CA
  12. 1.7 5km WSW of Lytle Creek, CA
  13. 1.5 12km ENE of Trabuco Canyon, CA
  14. 1.6 8km NNW of Cabazon, CA
  15. 1.9 8km NE of Yucaipa, 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.