Earthquake · reviewed by a seismologist
M 1.7ml
33 km SE of Cardston, Canada
Yes. A magnitude 1.7 earthquake was recorded 33 km SE of Cardston, Canada, at 7:06 pm MDT on 16 August 2021 (01:06 UTC), 18 km deep.
- When
- Magnitude
- M 1.7 (ml)
- Depth
- 18 km below the surface
- Felt
- no reports yet
- Nearest
- Glacier County, 35 km S
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1912 days ago
Earthquake alerts for North Browning, MT
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Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.
At this magnitude and depth it was probably too small to be felt, even directly above it. 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 12 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.
- Mineral, Virginia 2011 M 5.8 1,300,000× the energy of this one
- Magna, Utah 2020 M 5.7 900,000× the energy of this one
- Around the size people start to feel M 3.0 80× the energy of this one
- This earthquake M 1.7 about 12 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.
Where
Epicentre 49.0225, -112.9377. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Glacier County, MT | 35 km (22 mi) | S | earthquakes near Glacier County |
| Toole County, MT | 98 km (61 mi) | ESE | earthquakes near Toole County |
| Pondera County, MT | 103 km (64 mi) | SSE | earthquakes near Pondera County |
| Flathead County, MT | 115 km (71 mi) | SW | earthquakes near Flathead County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
17 earthquakes have been recorded within 50 km since this one.
- 2.3 40 km SSE of Magrath, Canada
- 2.3 6 km SSW of Cardston, Canada
- 1.7 21 km SSE of Cardston, Canada
- 2.0 43 km NNW of Santa Rita, Montana
- 2.4 38 km NNW of Santa Rita, Montana
- 1.9 40 km SSE of Magrath, Canada
- 1.5 20 km NW of Santa Rita, Montana
- 2.7 17 km NNW of Santa Rita, Montana
- 2.8 8 km S of Cardston, Canada
- 1.7 14 km S of Cardston, Canada
- 2.0 Alberta, Canada
- 1.9 35 km SE of Cardston, Canada
- 1.5 23 km NW of Santa Rita, Montana
- 2.4 22 km NW of Santa Rita, Montana
- 2.1 42 km NW of Santa Rita, 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
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.