M5.6 earthquake 103 km SE of Atka, Alaska
A magnitude 5.6 earthquake struck 103 km SE of Atka, Alaska on Fri, Jan 17, 1986, 3:59 PM HAST (01:59 UTC), 33 km (21 mi) below the surface.
Map
Where this earthquake was located, with the others nearby. Select one for its page.
The earthquake
- Magnitude
- 5.6 (Mw, moment), moderate
- Magnitude from
- USGS National Earthquake Information Center
- Local time
- UTC
- 1986-01-18 01:59:01 UTC
- Depth
- 33.0 km (20.5 mi), shallow
- Epicenter
- 51.553° N, 173.109° W
- Region
- Alaska
- 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 |
|---|---|---|---|
| 5.6 | Mw, moment | USGS National Earthquake Information Center | Preferred · Reviewed |
| 5.53 | Mw, moment | ISC-GEM global catalog | Final · ±0.1 |
| 5.55 | Mw, moment | USGS historic United States catalog | Final |
| 5.5 | Mwc, centroid moment | Global CMT project | Preliminary |
What happened
The USGS’s account of the effects of this earthquake.
CENTROID, MOMENT TENSOR (HRV) Data Used: GDSN L.P.B.: 15S, 36C Centroid Location: Origin Time 01:59: 5.4 0.3 Lat 51.81N 0.05 Lon 173.01W 0.04 Dep 35.8 2.3 Half-duration 2.0 Moment Tensor; Scale 10**24 D-CM Mrr=2.24 0.06 Mtt=0.23 0.07 Mff=-2.47 0.07 Mrt=0.42 0.12 Mrf=-0.22 0.15 Mtf=-0.46 0.08 Principal Axes: (T) Val=2.35 Plg=77 Azm=17 (N) Val=0.20 Plg=13 Azm=189 (P) Val=-2.55 Plg=2 Azm=279 Best Double Couple:Mo=2.4*10**24 NP1:Strike=22 Dip=45 Slip=108 NP2:Strike=177 Dip=48 Slip=73
Maximum observed Modified Mercalli Intensity (MMI) I
From the USGS event page for usp0002q6b. 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.
How well it is located
Reviewed by a seismologist.
- Depth from
- OPERATOR_ASSIGNED
Nearby
Within 100 km, magnitude 2.6 and up: 1 in the 60 days after this one and 0 in the 30 days before it.
After
Earthquakes todayAlaska earthquakesLive radar here
Sources
From the USGS Earthquake Hazards Program and its partner networks, event usp0002q6b (also filed as gcmtb011886a, ushis3917, gcmt19860118015905, iscgem506224). Read Sun, Oct 4, 2026, 3:30 PM UTC.