15 km NNW of Lima, Montana

Yes. A magnitude 1.7 earthquake was recorded 15 km NNW of Lima, Montana, at 2:35 pm MDT on 20 March 2024 (20:35 UTC), 8.7 km deep.

2024-03-20 20:35 UTC · 8.7 km deep · released about 11 lb of TNT

Felt it? Tell USGS Check my area

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: 2024-03-20 20:35 UTC
Montana today: every earthquake in Montana in the last 24 hours
Magnitude: M 1.7 (ml)
Depth: 8.7 km below the surface
Felt: no reports yet
Nearest: Beaverhead County, 44 km NNW
Nearest mapped fault: Red Rock fault, 7 km from its surface trace — near is not the same as on
Status: Reviewed by a seismologist

USGS · last changed by USGS 966 days ago · we first saw it 966 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 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 11 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 5.7 930,000× the energy of this one
Around the size people start to feel M 3.0 83× the energy of this one
This earthquake M 1.7 about 11 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 4.6 on 2019-04-09 — about 21,000 times the energy of this one.

Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:

5.1 19 km NW of Lima, Montana · 4 km WNW of this epicentre Jan 6, 1965
5.1 22 km NW of Lima, Montana · 8 km WNW of this epicentre Aug 20, 1999

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

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Nearby places

Place	Distance	Direction from the epicentre
Beaverhead County, MT	44 km (28 mi)	NNW	earthquakes near Beaverhead County
Clark County, ID	59 km (37 mi)	SSE	earthquakes near Clark County
Madison County, MT	88 km (55 mi)	NE	earthquakes near Madison County
Lemhi County, ID	95 km (59 mi)	WNW	earthquakes near Lemhi County
Jefferson County, ID	111 km (69 mi)	SSE	earthquakes near Jefferson County
Fremont County, ID	114 km (71 mi)	ESE	earthquakes near Fremont County

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

Aftershocks so far

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

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 14:46 UTC. 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.