M5.1 earthquake 46 km SSW of Adak, Alaska
A magnitude 5.1 earthquake struck 46 km SSW of Adak, Alaska on Fri, Dec 19, 1986, 3:50 AM HAST (13:50 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
- 5.1 (Mw, moment), moderate
- Magnitude from
- USGS National Earthquake Information Center
- Local time
- UTC
- 1986-12-19 13:50:10 UTC
- Depth
- 33.0 km (20.5 mi), shallow
- Epicenter
- 51.517° N, 176.977° 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 |
|---|---|---|---|
| 5.1 | Mw, moment | USGS National Earthquake Information Center | Preferred · Reviewed |
| 5.04 | Mw, moment | ISC-GEM global catalog | Final · ±0.1 |
| 5.0 | Mwc, centroid moment | Global CMT project | Preliminary |
What happened
The USGS’s account of the effects of this earthquake.
Felt (V) on Adak. CENTROID, MOMENT TENSOR (HRV) Data Used: GDSN L.P.B.: 7S, 14C Centroid Location: Origin Time 13:50:13.9 1.0 Lat 52.33N 0.12 Lon 177.41W 0.23 Dep 49.312.1 Half-duration 1.4 Moment Tensor; Scale 10**23 D-CM Mrr=2.28 0.47 Mtt=-2.54 0.53 Mff=0.27 0.50 Mrt=2.67 0.81 Mrf=3.02 0.74 Mtf=1.14 0.77 Principal Axes: (T) Val=5.46 Plg=51 Azm=303 (N) Val=-1.72 Plg=27 Azm=71 (P) Val=-3.74 Plg=26 Azm=176 Best Double Couple:Mo=4.6*10**23 NP1:Strike=310 Dip=31 Slip=152 NP2:Strike=64 Dip=76 Slip=62
From the USGS event page for usp0003106. 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 2.1 and up: 4 in the 60 days after this one and 2 in the 30 days before it.
After
- 4.687 km SE of Adak, Alaska · 14520 days ago · 33 km deep · 84 km away
- 4.969 km SW of Adak, Alaska · 14515 days ago · 33 km deep · 25 km away
- 5.065 km ESE of Adak, Alaska · 14507 days ago · 33 km deep · 80 km away
- 4.681 km SSE of Adak, Alaska · 14503 days ago · 33 km deep · 71 km away
Before
Earthquakes todayAlaska earthquakesLive radar here
Sources
From the USGS Earthquake Hazards Program and its partner networks, event usp0003106 (also filed as gcmtb121986c, gcmt19861219135010, iscgem478845). Read Thu, Oct 1, 2026, 3:09 AM UTC.