QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7md

Earthquake near Yosemite Valley, CA

No earthquake was likely felt in Yosemite Valley in the 24 hours to 10:42 am PST (18:42 UTC). The last one was M 2.5, 22 km (14 mi) SE, at 7:51 am PDT on 28 August 2026, estimated intensity II (weak) in town. Every earthquake near Yosemite Valley

This page: a magnitude 1.7 earthquake was recorded 23 km (14 mi) southeast of Yosemite Valley, CA, at 4:55 am PST on 21 November 2020 (12:55 UTC), 4.6 km deep.

USGS: 23km SE of Yosemite Valley, CA

4:55 am PST, Nov 21, 2020 · · 4.6 km deep · released about 9.6 lb of TNT

10 km30 km60 km120 km N Mariposa County 48 kmMono County 54 kmMadera County 57 kmTuolumne County 69 kmFresno County 100 kmAlpine County 117 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
4:55 am PST on 21 November 2020 ()
Where
23 km (14 mi) southeast of Yosemite Valley, CA · earthquakes near Yosemite Valley
Magnitude
M 1.7 (md)
Depth
4.6 km below the surface
Felt
no reports yet
Nearest
Mariposa County, 48 km W
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2182 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 11 km (7 mi) from the epicentre. In Yosemite Valley, 23 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.

How big was it?

This earthquake released about 9.6 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 1,600,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,100,000× the energy of this one
  3. Around the size people start to feel M 3.0 99× the energy of this one
  4. This earthquake M 1.7 about 9.6 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 2020-02-01 — about 13,000 times the energy of this one.

Before 2016, the USGS record lists 14 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.1 11 km WNW of Aspen Springs, California · 47 km E of this epicentre
  2. 6.1 8 km W of Aspen Springs, California · 50 km E of this epicentre
  3. 6.0 7 km ENE of Mammoth Lakes, California · 41 km E of this epicentre
  4. 5.9 8 km NNE of Mammoth Lakes, California · 40 km ENE of this epicentre
  5. 5.9 11 km SE of Mammoth Lakes, California · 44 km E 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 37.6268, -119.3657. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Mariposa County, CA 48 km (30 mi) W earthquakes near Mariposa County
Mono County, CA 54 km (33 mi) NE earthquakes near Mono County
Madera County, CA 57 km (36 mi) SW earthquakes near Madera County
Tuolumne County, CA 69 km (43 mi) NW earthquakes near Tuolumne County
Fresno County, CA 100 km (62 mi) SSW earthquakes near Fresno County
Alpine County, CA 117 km (73 mi) NNW earthquakes near Alpine County

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

Aftershocks so far

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

  1. 2.2 13km W of Toms Place, CA
  2. 1.9 13km W of Toms Place, CA
  3. 1.8 13km W of Toms Place, CA
  4. 2.0 15km SE of Mammoth Lakes, CA
  5. 1.6 12km ESE of Mammoth Lakes, CA
  6. 1.7 17km SSE of Mammoth Lakes, CA
  7. 2.6 18km WSW of Toms Place, CA
  8. 2.5 18km SE of Mammoth Lakes, CA
  9. 2.2 13km W of Toms Place, CA
  10. 1.6 4km E of Mammoth Lakes, CA
  11. 2.6 4km E of Mammoth Lakes, CA
  12. 1.9 17km SSE of Mammoth Lakes, CA
  13. 1.9 13km SE of Mammoth Lakes, CA
  14. 1.8 18km ESE of Yosemite Valley, CA
  15. 2.0 12km E of Mammoth Lakes, 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.