M3.7 earthquake 193 km S of Adak, Alaska
A magnitude 3.7 earthquake struck 193 km S of Adak, Alaska on Wed, Jun 20, 2018, 7:48 PM HADT (04:48 UTC), 10 km (6 mi) below the surface.
A larger quake followed: M4.8 236 km SSW of Adak, Alaska. This one was a foreshock.
Map
Where this earthquake was located, with the others nearby. Select one for its page.
The earthquake
- Magnitude
- 3.7 (mb, body-wave), minor
- Magnitude from
- USGS National Earthquake Information Center
- Local time
- UTC
- 2018-06-21 04:48:13 UTC
- Depth
- 10.0 km (6.2 mi), shallow
- Epicenter
- 50.165° N, 177.140° 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 |
|---|---|---|---|
| 3.7 | mb, body-wave | USGS National Earthquake Information Center | Preferred · Reviewed · ±0.091 · 31 stations |
| 3.3 | ML, local (Richter) | Alaska Earthquake Center | Preliminary |
Did you feel it?
No one has reported feeling this quake to the USGS.
How well it is located
Reviewed by a seismologist.
- Location uncertainty
- About 4.9 km horizontally, 2.0 km in depth
- Magnitude uncertainty
- ±0.09
- Depth from
- Operator assigned
- Station coverage gap
- 217°, poorly surrounded by stations
- Stations used
- 61
Nearby
Within 100 km, magnitude 1.5 and up: 8 in the 60 days after this one and 1 in the 30 days before it.
After
- 2.1169 km SSW of Adak, Alaska · 3024 days ago · 36 km deep · 33 km away
- 2.2187 km S of Adak, Alaska · 3021 days ago · 9 km deep · 12 km away
- 3.1180 km S of Adak, Alaska · 3005 days ago · 29 km deep · 61 km away
- 2.2176 km S of Adak, Alaska · 3005 days ago · 33 km deep · 64 km away
- 2.3229 km SSW of Adak, Alaska · 2997 days ago · 5 km deep · 47 km away
- 4.8236 km SSW of Adak, Alaska · 2975 days ago · 27 km deep · 81 km away
- 2.6231 km SSW of Adak, Alaska · 2974 days ago · 10 km deep · 83 km away
- 2.8247 km SSW of Adak, Alaska · 2972 days ago · 35 km deep · 89 km away
Before
Earthquakes todayAlaska earthquakesLive radar here
Sources
From the USGS Earthquake Hazards Program and its partner networks, event us1000f2bd (also filed as ak0187wj3quv, ak19790994). Read Fri, Oct 2, 2026, 11:32 AM UTC.