Idaho earthquakes

M5.4 earthquake 29 km NW of Mackay, Idaho

A magnitude 5.4 earthquake struck 29 km NW of Mackay, Idaho on Fri, Oct 28, 1983, 1:51 PM MDT (19:51 UTC), 7 km (5 mi) below the surface.

A larger quake followed: M5.5 22 km E of Clayton, Idaho. This one was a foreshock.

Challis forecast More in Idaho

Map

Where this earthquake was located, with the others nearby. Select one for its page.

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The earthquake

Magnitude: 5.4 (mb, body-wave), moderate
Magnitude from: USGS National Earthquake Information Center
Local time: Fri, Oct 28, 1983, 1:51 PM MDT
UTC: 1983-10-28 19:51:24 UTC
Depth: 7.4 km (4.6 mi), shallow
Epicenter: 44.073° N, 113.911° W
Region: Idaho
Tsunami flag: No
Status: Reviewed by a seismologist

Magnitude estimates

Different scales measure different things and differ by a few tenths. The USGS marks one as preferred, and it is the one this page uses.

Mag.	Scale	Computed by	Notes
5.4	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · 42 stations
5.56	Mw, moment	ISC-GEM global catalog	Final · ±0.1
5.59	Mw, moment	USGS historic United States catalog	Final
5.6	Mwc, centroid moment	Global CMT project	Preliminary

What happened

The USGS’s account of the effects of this earthquake.

Felt in the Challis-Mackay area. CENTROID, MOMENT TENSOR SOLUTION HARVARD EVENT-FILE NAME B102883C DATA USED: GDSN L.P. BODY WAVES: 10S, 18C, T=45 CENTROID LOCATION: ORIGIN TIME 19:51:35.2 1.4 LAT 44.75N 0.21;LON 114.54W 0.25 DEP 10.0 FIX;HALF-DURATION 2.3 MOMENT TENSOR; SCALE 10**24 D-CM MRR=-1.03 0.17; MTT=0.37 0.21 MFF=0.66 0.22; MRT=0.43 0.66 MRF=2.28 0.61; MTF=-1.31 0.18 PRINCIPAL AXES: 1.(T) VAL=2.59;PLG=27;AZM=244 2.(N) 0.40; 29; 351 3.(P) -2.99; 48; 119 BEST DOUBLE COUPLE:M0=2.8*10**24 NP1:STRIKE=287;DIP=32;SLIP=-157 NP2:Strike=177;Dip=78;Slip=-60

Maximum observed Modified Mercalli Intensity (MMI) I

From the USGS event page for usp0001zcc. U.S. Geological Survey text and figures are in the public domain.

Did you feel it?

No one has reported feeling this quake to the USGS.

Nearest places

Distance and direction from each place to the epicenter, with its forecast.

Nearby

Within 100 km, magnitude 2.4 and up: 63 in the 60 days after this one and 9 in the 30 days before it.

After

The first 60 of 63.

Before

Earthquakes today Idaho earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event usp0001zcc (also filed as gcmtb102883c, ushis3825, gcmt19831028195124, iscgem567378). Read Sat, Oct 3, 2026, 10:48 AM UTC.