QuakeIndex

Earthquake · reviewed by a seismologist

M 1.9md

64 km SSW of Silver Gate, Montana

Yes. A magnitude 1.9 earthquake was recorded 64 km SSW of Silver Gate, Montana, at 5:36 pm MDT on 27 April 2023 (23:36 UTC), 11 km deep.

· 11 km deep · released about 22 lb of TNT

10 km30 km60 km120 km N Teton County 47 kmPark County 53 kmFremont County 101 kmTeton County 108 kmPark County 114 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 1.9 (md)
Depth
11 km below the surface
Felt
no reports yet
Nearest
Teton County, 47 km SSW
Nearest mapped fault
Buffalo Fork fault, 7 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 1293 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 10 km (6 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 22 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 680,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 480,000× the energy of this one
  3. Around the size people start to feel M 3.0 43× the energy of this one
  4. This earthquake M 1.9 about 22 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 4.2 on 2022-05-11 — about 2,900 times the energy of this one.

Before 2016, the USGS record lists 4 earthquakes of M5 or more within 50 km:

  1. 5.9 26 km SSE of Mammoth, Wyoming · 42 km NW of this epicentre
  2. 5.1 51 km ESE of West Yellowstone, Montana · 19 km WNW of this epicentre
  3. 5.1 23 km S of Mammoth, Wyoming · 50 km NW of this epicentre
  4. 5.0 62 km ESE of West Yellowstone, Montana · 11 km WSW 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 44.4563, -110.2603. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Teton County, WY 47 km (29 mi) SSW earthquakes near Teton County
Park County, WY 53 km (33 mi) E earthquakes near Park County
Fremont County, ID 101 km (63 mi) WSW earthquakes near Fremont County
Teton County, ID 108 km (67 mi) SW earthquakes near Teton County
Park County, MT 114 km (71 mi) N earthquakes near Park County
Carbon County, MT 129 km (80 mi) NE earthquakes near Carbon County

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

Aftershocks so far

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

  1. 2.0 37 km S of Silver Gate, Montana
  2. 3.3 37 km S of Silver Gate, Montana
  3. 1.8 38 km SSE of Mammoth, Wyoming
  4. 1.9 44 km SE of Mammoth, Wyoming
  5. 2.3 36 km S of Silver Gate, Montana
  6. 1.7 50 km SSE of Mammoth, Wyoming
  7. 1.6 50 km SSE of Mammoth, Wyoming
  8. 1.5 Wyoming
  9. 2.3 Wyoming
  10. 2.7 54 km NNE of Kelly, Wyoming
  11. 2.2 Wyoming
  12. 1.5 Wyoming
  13. 1.7 54 km NNE of Kelly, Wyoming
  14. 1.5 27 km ESE of West Yellowstone, Montana
  15. 1.7 46 km SSE of Mammoth, Wyoming

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.