M5.3 earthquake 20 km SSW of Susitna, Alaska
A magnitude 5.3 earthquake struck 20 km SSW of Susitna, Alaska on Fri, Apr 17, 1987, 6:01 PM AKDT (02:01 UTC), 68 km (42 mi) below the surface.
Map
Where this earthquake was located, with the others nearby. Select one for its page.
The earthquake
- Magnitude
- 5.3 (Mw, moment), moderate
- Magnitude from
- USGS National Earthquake Information Center
- Local time
- UTC
- 1987-04-18 02:01:38 UTC
- Depth
- 68.0 km (42.3 mi), shallow
- Epicenter
- 61.374° N, 150.656° 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 |
|---|---|---|---|
| 5.3 | Mw, moment | USGS National Earthquake Information Center | Preferred · Reviewed |
| 5.28 | Mw, moment | ISC-GEM global catalog | Final · ±0.1 |
| 5.32 | Mw, moment | USGS historic United States catalog | Final |
| 5.3 | Mwc, centroid moment | Global CMT project | Preliminary |
What happened
The USGS’s account of the effects of this earthquake.
Felt (V) at Anchorage, Eagle River, Palmer and Skwentna; (IV) at Chugiak, Cooper Landing, Fort Richardson, Seward, Sterling, Sutton, Talkeetna, Tyonek, Whittier and Willow; (II) at Cantwell, Homer, Kasilof, Kenai, Moose Pass, Nikishka and Valdez. CENTROID, MOMENT TENSOR (HRV) Data Used: GDSN L.P.B.: 15S, 35C Centroid Location: Origin Time 02:01:42.4 0.6 Lat 61.40N 0.06 Lon 150.22W 0.10 Dep 69.0 6.0 Half-duration 1.7 Moment Tensor; Scale 10**16 Nm Mrr=4.86 0.34 Mtt=-1.47 0.47 Mff=-3.39 0.50 Mrt=3.63 0.42 Mrf=8.92 0.47 Mtf=-1.30 0.66 Principal Axes: (T) Val=11.02 Plg=57 Azm=291 (N) Val=-0.83 Plg=1 Azm=23 (P) Val=-10.19 Plg=33 Azm=114 Best Double Couple:Mo=1.1*10**17 NP1:Strike=209 Dip=12 Slip=96 NP2:Strike=23 Dip=78 Slip=89
Maximum observed Modified Mercalli Intensity (MMI) V
From the USGS event page for usp000348h. 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 2.3 and up: 1 in the 60 days after this one and 1 in the 30 days before it.
After
Before
Earthquakes todayAlaska earthquakesLive radar here
Sources
From the USGS Earthquake Hazards Program and its partner networks, event usp000348h (also filed as gcmtb041887a, ushis4019, gcmt19870418020138, iscgem469434). Read Fri, Oct 2, 2026, 5:52 PM UTC.