QuakeIndex

Earthquake · reviewed by a seismologist

M 1.5md

68 km SSW of Silver Gate, Montana

Yes. A magnitude 1.5 earthquake was recorded 68 km SSW of Silver Gate, Montana, at 12:19 am MST on 2 December 2020 (07:19 UTC), 5.5 km deep.

· 5.5 km deep · released about 5.4 lb of TNT

10 km30 km60 km120 km N Teton County 44 kmPark County 50 kmFremont County 104 kmTeton County 108 kmPark County 120 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
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 1.5 (md)
Depth
5.5 km below the surface
Felt
no reports yet
Nearest
Teton County, 44 km SSW
Nearest mapped fault
Buffalo Fork fault, 8 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 2170 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.

How big was it?

This earthquake released about 5.4 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,800,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 2,000,000× the energy of this one
  3. Around the size people start to feel M 3.0 180× the energy of this one
  4. This earthquake M 1.5 about 5.4 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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

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

  1. 5.9 26 km SSE of Mammoth, Wyoming · 49 km NW of this epicentre
  2. 5.1 51 km ESE of West Yellowstone, Montana · 25 km WNW of this epicentre
  3. 5.0 62 km ESE of West Yellowstone, Montana · 15 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 44.4107, -110.2097. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Teton County, WY 44 km (27 mi) SSW earthquakes near Teton County
Park County, WY 50 km (31 mi) E earthquakes near Park County
Fremont County, ID 104 km (64 mi) WSW earthquakes near Fremont County
Teton County, ID 108 km (67 mi) SW earthquakes near Teton County
Park County, MT 120 km (74 mi) NNW earthquakes near Park County
Carbon County, MT 130 km (81 mi) NE earthquakes near Carbon County

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

Aftershocks so far

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

  1. 2.0 55 km SE of West Yellowstone, Montana
  2. 2.3 55 km SE of West Yellowstone, Montana
  3. 1.5 55 km SE of West Yellowstone, Montana
  4. 1.8 56 km SE of West Yellowstone, Montana
  5. 2.0 28 km S of Mammoth, Wyoming
  6. 2.1 28 km S of Mammoth, Wyoming
  7. 2.2 27 km SSE of Mammoth, Wyoming
  8. 1.7 48 km ESE of West Yellowstone, Montana
  9. 1.8 35 km SSW of Silver Gate, Montana
  10. 2.1 65 km NNE of Kelly, Wyoming
  11. 2.2 28 km SE of Mammoth, Wyoming
  12. 1.7 31 km SSE of Mammoth, Wyoming
  13. 2.3 36 km S of Silver Gate, Montana
  14. 1.6 41 km S of Silver Gate, Montana
  15. 1.8 38 km S of Silver Gate, Montana

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.