Reviewed by USGSAlaska4y ago
M3.1 earthquake 7 km WSW of Unalaska, Alaska
Sunday, May 22, 2022, 01:37:48 UTC · 53.842°N, 166.629°W
A magnitude 3.1 earthquake struck 7 km WSW of Unalaska, Alaska on Sunday, May 22, 2022, 01:37:48 UTC, at a depth of 10.0 km (shallow).
- Magnitude
- 3.1
- Minor · ml
- Depth
- 10 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
674 kg of TNT
That is about 1/22,353 of the Hiroshima bomb. A magnitude 5.0 releases about 708 times more energy.
Tectonic setting
155 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
10 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 2 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M2.6 on June 17, 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 627 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 · 253 km E of this epicenter
- 7.881 km E of Nikolski, AlaskaJuly 2, 1965 · 115 km SW of this epicenter
- 7.4133 km WNW of Nikolski, AlaskaApril 18, 1916 · 270 km W of this epicenter
- 7.139 km S of Akutan, AlaskaMarch 22, 1957 · 57 km E of this epicenter
- 7.135 km SW of Nikolski, AlaskaMarch 11, 1957 · 213 km SW of this epicenter
- 7.0203 km SSE of Unalaska, AlaskaAugust 22, 1940 · 202 km S of this epicenter
- 6.980 km SW of Nikolski, AlaskaMarch 9, 1957 · 256 km SW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 12 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 · 253 km away · intensity VI
168 deaths$26 million damagetsunami
- 1965M6.5
Aleutian Islands: Fox Islands
2 Jul 1965 · 109 km away
Limited damage (under $1M)tsunami
- 1917M7.9
Alaska Peninsula
31 May 1917 · 193 km away · intensity V
- 1902M7.8
Aleutian Islands: Fox Islands
1 Jan 1902 · 171 km away
- 1907M7.8
Aleutian Islands
2 Sep 1907 · 249 km away
- 1916M7.5
Aleutian Islands: Fox Islands
18 Apr 1916 · 231 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.