QuakeIndex

Earthquake · reviewed by a seismologist

M 3.9mw

28km SSW of Smith Valley, NV

Yes. A magnitude 3.9 earthquake was recorded 28km SSW of Smith Valley, NV, at 8:46 pm PDT on 13 July 2021 (03:46 UTC), 2.0 km deep. 29 people have reported feeling it to USGS.

· 2.0 km deep · released about 10 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Alpine County 30 kmDouglas County 42 kmLyon County 57 kmCarson City 72 kmTuolumne County 73 kmMono County 87 kmMineral County 91 kmEl Dorado County 97 kmStorey County 99 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
Magnitude
M 3.9 (mw)
Depth
2.0 km below the surface
Felt
29 reports · strongest reported intensity IV
Measured shaking
intensity IV (ShakeMap)
Nearest
Alpine County, 30 km WNW
Nearest mapped fault
Antelope Valley fault, under 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 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 89 km (55 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: Topaz Ranch Estates 21 km, intensity III · Gardnerville Ranchos 45 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 10 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 16,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 730× the energy of this one
  3. Magna, Utah 2020 M 5.7 520× the energy of this one
  4. This earthquake M 3.9 about 10 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 22× 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 1,500 times the energy of this one.

Before 2016, the USGS record lists 6 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.1 4 km S of Carter Springs, Nevada · 34 km NNW of this epicentre
  2. 5.2 23 km S of Walker, California · 28 km S of this epicentre
  3. 5.1 19 km W of Bridgeport, California · 36 km S of this epicentre
  4. 5.1 8 km ESE of Mesa Vista, California · 33 km NW of this epicentre
  5. 5.0 Near Coleville, California · 5 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 38.5487, -119.4605. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Alpine County, CA 30 km (19 mi) WNW earthquakes near Alpine County
Douglas County, NV 42 km (26 mi) NNW earthquakes near Douglas County
Lyon County, NV 57 km (36 mi) NNE earthquakes near Lyon County
Carson City, NV 72 km (45 mi) NNW earthquakes near Carson City
Tuolumne County, CA 73 km (46 mi) SW earthquakes near Tuolumne County
Mono County, CA 87 km (54 mi) SE earthquakes near Mono County

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. 1.6 27km S of Smith Valley, NV
  2. 2.3 27km S of Smith Valley, NV
  3. 1.5 33km ENE of Dardanelle, CA
  4. 1.9 30km SSW of Smith Valley, NV
  5. 2.2 28km SSW of Smith Valley, NV
  6. 2.2 28km SSW of Smith Valley, NV
  7. 1.7 30km SE of Markleeville, CA
  8. 1.6 30km ENE of Dardanelle, CA
  9. 1.6 30km SSW of Smith Valley, NV
  10. 1.7 28km S of Smith Valley, NV
  11. 1.9 28km S of Smith Valley, NV
  12. 1.9 29km SSW of Smith Valley, NV
  13. 1.6 27km SSW of Smith Valley, NV
  14. 1.6 30km SSW of Smith Valley, NV
  15. 1.6 31km S of Smith Valley, NV

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.