Reviewed by USGSAlaska2y ago
M2.7 earthquake 21 km W of Cold Bay, Alaska
Wednesday, December 20, 2023, 11:47:51 UTC · 55.215°N, 163.058°W
A magnitude 2.7 earthquake struck 21 km W of Cold Bay, Alaska on Wednesday, December 20, 2023, 11:47:51 UTC, at a depth of 129.5 km (intermediate).
- Magnitude
- 2.7
- Minor · ml
- Depth
- 129 km
- Intermediate
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- —
- No ShakeMap
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquake
In context
How big was it, and why here?
Energy released
169 kg of TNT
That is about 1/88,990 of the Hiroshima bomb. A magnitude 5.0 releases about 2,818 times more energy.
Tectonic setting
207 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: intermediate
129 km
Intermediate-depth earthquakes usually break inside a plate that is sinking into the mantle. Shaking spreads over a wide area but is gentler at the epicenter than a shallow quake of the same size.
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 has not published any M2.5+ earthquake within 50 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 383 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 · 192 km S of this epicenter
- 7.82020 Perryville, Alaska EarthquakeJuly 22, 2020 · 284 km E of this epicenter
- 7.62020 Sand Point, Alaska EarthquakeOctober 19, 2020 · 230 km E of this epicenter
- 7.454 km SE of Sand Point, AlaskaMay 31, 1917 · 203 km E of this epicenter
- 7.22023 Sand Point, Alaska EarthquakeJuly 16, 2023 · 173 km SE of this epicenter
- 7.190 km SE of King Cove, AlaskaMay 14, 1948 · 140 km SE of this epicenter
- 7.139 km S of Akutan, AlaskaMarch 22, 1957 · 237 km SW of this epicenter
- 7.071 km SE of King Cove, AlaskaMay 30, 1991 · 118 km SE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 11 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 169 recorded deaths. The most severe:
- 1946M8.6
Unimak Island
1 Apr 1946 · 192 km away · intensity VI
168 deaths$26 million damagetsunami
- 2023M7.2
Alaska Peninsula
16 Jul 2023 · 169 km away · intensity VI
1 deathtsunami
- 2020M7.8
Alaska
22 Jul 2020 · 284 km away · intensity VII
Limited damage (under $1M)tsunami
- 1938M8.2
Alaska
10 Nov 1938 · 298 km away · intensity VI
tsunami
- 1788M8.0
Alaska Peninsula
6 Aug 1788 · 133 km away
tsunami
- 2020M7.6
Alaska
19 Oct 2020 · 230 km away · intensity IX
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.