QuakeIndex

Earthquake · reviewed by a seismologist

M 3.9ml

Earthquake near Topaz Ranch Estates, NV

No earthquake was likely felt in Topaz Ranch Estates in the 24 hours to 9:20 am PST (17:20 UTC). The last one was M 2.3, 8 km (5 mi) SW, at 6:36 pm PDT on 29 September 2026, estimated intensity II (weak) in town. Every earthquake near Topaz Ranch Estates

This page: a magnitude 3.9 earthquake was recorded 31 km (19 mi) south of Topaz Ranch Estates, NV, at 5:05 pm PDT on 8 July 2021 (00:05 UTC), 4.8 km deep. 29 people have reported feeling it to USGS.

USGS: 31km NW of Bridgeport, CA

5:05 pm PDT, Jul 8, 2021 · · 4.8 km deep · released about 11 tons of TNT

10 km30 km60 km120 km N Alpine County 33 kmDouglas County 51 kmTuolumne County 64 kmLyon County 68 kmMono County 80 kmCarson City 81 kmMineral County 93 kmCalaveras County 98 kmEl Dorado County 98 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
5:05 pm PDT on 8 July 2021 ()
Where
31 km (19 mi) south of Topaz Ranch Estates, NV · earthquakes near Topaz Ranch Estates
Magnitude
M 3.9 (ml)
Depth
4.8 km below the surface
Felt
29 reports · strongest reported intensity IV
Measured shaking
intensity IV (ShakeMap)
USGS impact alert
green
Nearest
Alpine County, 33 km NW
Nearest mapped fault
Antelope Valley fault, 2 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 1882 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 91 km (57 mi) from the epicentre. In Topaz Ranch Estates, 31 km away, the estimate is intensity III (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: Topaz Ranch Estates 31 km, intensity III. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 11 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.9 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 15,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 660× the energy of this one
  3. Magna, Utah 2020 M 5.7 470× the energy of this one
  4. This earthquake M 3.9 about 11 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 24× more

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 6.0 on 2021-07-08 — about 1,300 times the energy of this one.

Before 2016, the USGS record lists 7 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.1 4 km S of Carter Springs, Nevada · 43 km NNW of this epicentre
  2. 5.2 23 km S of Walker, California · 17 km S of this epicentre
  3. 5.1 23 km E of Bridgeport, California · 49 km ESE of this epicentre
  4. 5.1 19 km W of Bridgeport, California · 26 km S of this epicentre
  5. 5.1 8 km ESE of Mesa Vista, California · 40 km NNW 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 38.4563, -119.4825. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Alpine County, CA 33 km (21 mi) NW earthquakes near Alpine County
Douglas County, NV 51 km (32 mi) NNW earthquakes near Douglas County
Tuolumne County, CA 64 km (40 mi) SW earthquakes near Tuolumne County
Lyon County, NV 68 km (42 mi) NNE earthquakes near Lyon County
Mono County, CA 80 km (50 mi) SE earthquakes near Mono County
Carson City, NV 81 km (50 mi) NNW earthquakes near Carson City

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

Aftershocks so far

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

  1. 2.1 2 km S of Coleville, California
  2. 2.7 32km ENE of Dardanelle, CA
  3. 1.7 7 km SW of Walker, California
  4. 2.6 28km ENE of Dardanelle, CA
  5. 1.9 6 km W of Walker, California
  6. 1.9 3 km WNW of Walker, California
  7. 2.9 31km SE of Markleeville, CA
  8. 2.3 31km SE of Markleeville, CA
  9. 2.9 30km ENE of Dardanelle, CA
  10. 2.3 3 km SSW of Coleville, California
  11. 3.2 30km SE of Markleeville, CA
  12. 2.4 31km SE of Markleeville, CA
  13. 2.3 32km ENE of Dardanelle, CA
  14. 2.7 30km SE of Markleeville, CA
  15. 1.8 19 km E of Walker, California

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.