quarry blast · reviewed by a seismologist
M 1.8ml
Earthquake near Bozeman, MT
No earthquake was likely felt in Bozeman in the 24 hours to 4:50 pm MST (23:50 UTC). The last one was M 3.0, 17 km (10 mi) NW, at 7:42 am MDT on 1 June 2024, estimated intensity II (weak) in town; 20 felt reports to USGS. Every earthquake near Bozeman
No: USGS classifies this as a quarry blast, not an earthquake. A magnitude 1.8 quarry blast was recorded 40 km (25 mi) northwest of Bozeman, MT, at 12:03 pm MDT on 26 September 2018 (18:03 UTC), less than 1 km deep.
USGS: 3 km N of Logan, Montana
39 km (24 mi) NW of Bozeman, MT
- When
- 12:03 pm MDT on 26 September 2018 ()
- Where
- 40 km (25 mi) northwest of Bozeman, MT · earthquakes near Bozeman
- Montana today
- every earthquake in Montana in the last 24 hours
- Magnitude
- M 1.8 (ml)
- Depth
- -2.0 km below the surface
- Felt
- no reports yet
- Nearest
- Broadwater County, 46 km N
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 2968 days ago
Earthquake alerts for Bozeman, MT
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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 13 km (8 mi) from the epicentre. In Bozeman, 40 km away, the estimate is intensity I (not felt). 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.
Likely felt in: Three Forks 10 km, intensity II · Manhattan 10 km, intensity II. Estimated for each town centre; each link is that town's own record.
USGS catalogues this as quarry blast, not an earthquake.
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 1,100,000× the energy of this one
- Magna, Utah 2020 M 5.7 810,000× the energy of this one
- Around the size people start to feel M 3.0 72× 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
No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.
Before 2016, the USGS record lists 6 earthquakes of M5 or more within 50 km; the five largest:
- 6.6 The 1925 Clarkston Valley, Montana Earthquake · 19 km NNW of this epicentre
- 6.4 Clarkston Valley, Montana (Aftershock) · 19 km NNW of this epicentre
- 5.5 Clarkston Valley, Montana (Aftershock) · 19 km NNW of this epicentre
- 5.5 Clarkston Valley, Montana (Aftershock) · 19 km NNW of this epicentre
- 5.5 Clarkston Valley, Montana (Aftershock) · 19 km NNW 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 45.9193, -111.4275. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Broadwater County, MT | 46 km (29 mi) | N | earthquakes near Broadwater County |
| Gallatin County, MT | 49 km (31 mi) | SSE | earthquakes near Gallatin County |
| Jefferson County, MT | 54 km (33 mi) | WNW | earthquakes near Jefferson County |
| Madison County, MT | 76 km (47 mi) | SSW | earthquakes near Madison County |
| Meagher County, MT | 84 km (52 mi) | NNE | earthquakes near Meagher County |
| Park County, MT | 86 km (53 mi) | SE | earthquakes near Park 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.
- 1.7 1 km W of Manhattan, Montana
- 2.3 5 km SSE of Logan, Montana
- 1.5 1 km W of Manhattan, Montana
- 1.5 7 km SSW of The Silos, Montana
- 1.6 1 km W of Manhattan, Montana
- 2.1 2 km W of Manhattan, Montana
- 1.7 1 km WSW of Manhattan, Montana
- 2.1 2 km W of Manhattan, Montana
- 2.2 1 km W of Manhattan, Montana
- 1.6 2 km WNW of Manhattan, Montana
- 1.7 3 km NW of Manhattan, Montana
- 1.6 1 km WNW of Manhattan, Montana
- 1.8 2 km WNW of Manhattan, Montana
- 1.6 3 km WNW of Manhattan, Montana
- 2.3 2 km WSW of Manhattan, 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.