Earthquake · reviewed by a seismologist
M 1.8ml
22 km WNW of Stanley, Idaho
Yes. A magnitude 1.8 earthquake was recorded 22 km WNW of Stanley, Idaho, at 12:30 am MDT on 2 September 2020 (06:30 UTC), 9.1 km deep.
- When
- Idaho today
- every earthquake in Idaho in the last 24 hours
- Magnitude
- M 1.8 (ml)
- Depth
- 9.1 km below the surface
- Felt
- no reports yet
- Nearest
- Boise County, 53 km SW
- Nearest mapped fault
- Sawtooth fault, 3 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 2262 days ago
Earthquake alerts for Challis, ID
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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, people at rest would likely notice it out to about 9 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 13 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 1,200,000× the energy of this one
- Magna, Utah 2020 M 5.7 840,000× the energy of this one
- Around the size people start to feel M 3.0 75× the energy of this one
- This earthquake M 1.8 about 13 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 6.5 on 2020-03-31 — about 13,000,000 times the energy of this one.
Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:
- 6.1 37 km N of Stanley, Idaho · 38 km NE of this epicentre
- 6.0 44 km NNW of Stanley, Idaho · 36 km NNE 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 44.2940, -115.2003. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Boise County, ID | 53 km (33 mi) | SW | earthquakes near Boise County |
| Valley County, ID | 71 km (44 mi) | NNW | earthquakes near Valley County |
| Custer County, ID | 76 km (47 mi) | E | earthquakes near Custer County |
| Camas County, ID | 94 km (59 mi) | SSE | earthquakes near Camas County |
| Gem County, ID | 99 km (62 mi) | WSW | earthquakes near Gem County |
| Elmore County, ID | 102 km (64 mi) | SSW | earthquakes near Elmore 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.
- 1.9 15 km SW of Stanley, Idaho
- 2.3 41 km NNW of Stanley, Idaho
- 2.3 37 km NW of Stanley, Idaho
- 2.4 34 km NW of Stanley, Idaho
- 3.2 27 km NW of Stanley, Idaho
- 2.4 19 km WNW of Stanley, Idaho
- 2.6 46 km SSE of Yellow Pine, Idaho
- 2.2 37 km NW of Stanley, Idaho
- 3.2 21 km WNW of Stanley, Idaho
- 2.2 29 km NW of Stanley, Idaho
- 2.3 36 km NW of Stanley, Idaho
- 2.5 47 km NW of Stanley, Idaho
- 2.1 34 km NW of Stanley, Idaho
- 2.2 34 km NW of Stanley, Idaho
- 1.9 35 km NW of Stanley, Idaho
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.