Reviewed by USGSAlaska4y ago
M2.9 earthquake in Unimak Island region, Alaska
Friday, April 15, 2022, 02:12:42 UTC · 54.189°N, 164.990°W
A magnitude 2.9 earthquake struck in Unimak Island region, Alaska on Friday, April 15, 2022, 02:12:42 UTC, at a depth of 78.1 km (intermediate).
- Magnitude
- 2.9
- Minor · ml
- Depth
- 78 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 earthquakeDashed circle: 50 km aftershock search area
In context
How big was it, and why here?
Energy released
338 kg of TNT
That is about 1/44,601 of the Hiroshima bomb. A magnitude 5.0 releases about 1,413 times more energy.
Tectonic setting
149 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
78 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 lists 4 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M3.7 on April 25, 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 461 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 · 161 km SE of this epicenter
- 7.881 km E of Nikolski, AlaskaJuly 2, 1965 · 219 km SW of this epicenter
- 7.190 km SE of King Cove, AlaskaMay 14, 1948 · 252 km E of this epicenter
- 7.139 km S of Akutan, AlaskaMarch 22, 1957 · 69 km SW of this epicenter
- 7.071 km SE of King Cove, AlaskaMay 30, 1991 · 223 km E of this epicenter
- 7.0203 km SSE of Unalaska, AlaskaAugust 22, 1940 · 228 km S of this epicenter
- 6.980 km E of Nikolski, AlaskaMarch 24, 1980 · 223 km SW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 10 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 · 161 km away · intensity VI
168 deaths$26 million damagetsunami
- 1965M6.5
Aleutian Islands: Fox Islands
2 Jul 1965 · 212 km away
Limited damage (under $1M)tsunami
- 1788M8.0
Alaska Peninsula
6 Aug 1788 · 272 km away
tsunami
- 1917M7.9
Alaska Peninsula
31 May 1917 · 275 km away · intensity V
- 1902M7.8
Aleutian Islands: Fox Islands
1 Jan 1902 · 260 km away
- 1948M7.5
Alaska Peninsula
14 May 1948 · 261 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.