Reviewed by USGSAlaska5y ago
M2.7 earthquake 77 km ESE of King Cove, Alaska
Monday, May 31, 2021, 18:40:57 UTC · 54.704°N, 161.287°W
A magnitude 2.7 earthquake struck 77 km ESE of King Cove, Alaska on Monday, May 31, 2021, 18:40:57 UTC, at a depth of 34.1 km (shallow).
- Magnitude
- 2.7
- Minor · ml
- Depth
- 34 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
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
122 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
34 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 4 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M3.8 on June 12, 2021. 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 374 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 · 168 km SW of this epicenter
- 8.21938 Semidi Islands, Alaska EarthquakeNovember 10, 1938 · 205 km E of this epicenter
- 7.82020 Perryville, Alaska EarthquakeJuly 22, 2020 · 177 km E of this epicenter
- 7.62020 Sand Point, Alaska EarthquakeOctober 19, 2020 · 107 km E of this epicenter
- 7.454 km SE of Sand Point, AlaskaMay 31, 1917 · 96 km E of this epicenter
- 7.190 km SE of King Cove, AlaskaMay 14, 1948 · 15 km SE of this epicenter
- 7.071 km SE of King Cove, AlaskaMay 30, 1991 · 26 km SW of this epicenter
- 6.9105 km ESE of Perryville, AlaskaNovember 17, 1938 · 240 km E 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 168 recorded deaths. The most severe:
- 1946M8.6
Unimak Island
1 Apr 1946 · 168 km away · intensity VI
168 deaths$26 million damagetsunami
- 2020M7.8
Alaska
22 Jul 2020 · 177 km away · intensity VII
Limited damage (under $1M)tsunami
- 1938M8.2
Alaska
10 Nov 1938 · 205 km away · intensity VI
tsunami
- 2021M8.2
Alaska Peninsula
29 Jul 2021 · 230 km away · intensity VIII
tsunami
- 1788M8.0
Alaska Peninsula
6 Aug 1788 · 38 km away
tsunami
- 2020M7.6
Alaska
19 Oct 2020 · 107 km away · intensity IX
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.