Reviewed by USGSAlaska4y ago
M2.6 earthquake 82 km E of Akutan, Alaska
Monday, December 27, 2021, 02:05:46 UTC · 54.133°N, 164.508°W
A magnitude 2.6 earthquake struck 82 km E of Akutan, Alaska on Monday, December 27, 2021, 02:05:46 UTC, at a depth of 49.8 km (shallow).
- Magnitude
- 2.6
- Minor · ml
- Depth
- 50 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- —
- No ShakeMap
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeDashed circle: 50 km aftershock search area
In context
How big was it, and why here?
Energy released
120 kg of TNT
That is about 1/125,702 of the Hiroshima bomb. A magnitude 5.0 releases about 3,981 times more energy.
Tectonic setting
131 km
from the nearest mapped plate boundary, between the North American and Pacific plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: shallow
50 km
Shallow earthquakes (under 70 km) produce the strongest surface shaking for their size, so they are the ones most likely to cause damage near the epicenter.
Did You Feel It?
Where it was felt
No “Did You Feel It?” reports have been published for this event yet. If you felt it, you can add your report on the USGS website.
I felt it — report to USGS ↗USGS PAGER estimate
Who was exposed to shaking
USGS publishes PAGER impact estimates for significant earthquakes, usually within an hour. No PAGER estimate is available for this event.
After the main event
Aftershocks within 50 km
USGS lists 3 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M3.1 on January 12, 2022. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 456 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.6The 1946 Unimak Island, Alaska EarthquakeApril 1, 1946 · 131 km SE of this epicenter
- 7.881 km E of Nikolski, AlaskaJuly 2, 1965 · 242 km SW of this epicenter
- 7.190 km SE of King Cove, AlaskaMay 14, 1948 · 223 km E of this epicenter
- 7.139 km S of Akutan, AlaskaMarch 22, 1957 · 92 km SW of this epicenter
- 7.071 km SE of King Cove, AlaskaMay 30, 1991 · 194 km E of this epicenter
- 7.0203 km SSE of Unalaska, AlaskaAugust 22, 1940 · 229 km S of this epicenter
- 6.917 km S of Sand Point, AlaskaMay 13, 1993 · 285 km NE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 9 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 168 recorded deaths. The most severe:
- 1946M8.6
Unimak Island
1 Apr 1946 · 131 km away · intensity VI
168 deaths$26 million damagetsunami
- 1965M6.5
Aleutian Islands: Fox Islands
2 Jul 1965 · 235 km away
Limited damage (under $1M)tsunami
- 1788M8.0
Alaska Peninsula
6 Aug 1788 · 246 km away
tsunami
- 1902M7.8
Aleutian Islands: Fox Islands
1 Jan 1902 · 277 km away
- 1948M7.5
Alaska Peninsula
14 May 1948 · 231 km away
- 1957M7.5
Aleutian Islands: Fox Islands
22 Mar 1957 · 106 km away · intensity V
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.