Reviewed by USGSAlaska2y ago
M3.2 earthquake 52 km WSW of Unalaska, Alaska
Saturday, March 23, 2024, 20:09:35 UTC · 53.722°N, 167.285°W
A magnitude 3.2 earthquake struck 52 km WSW of Unalaska, Alaska on Saturday, March 23, 2024, 20:09:35 UTC, at a depth of 106.7 km (intermediate).
- Magnitude
- 3.2
- Minor · ml
- Depth
- 107 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
951 kg of TNT
That is about 1/15,825 of the Hiroshima bomb. A magnitude 5.0 releases about 501 times more energy.
Tectonic setting
160 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
107 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 M4.4 on April 4, 2024. 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 668 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 · 295 km E of this epicenter
- 7.881 km E of Nikolski, AlaskaJuly 2, 1965 · 83 km S of this epicenter
- 7.4133 km WNW of Nikolski, AlaskaApril 18, 1916 · 225 km W of this epicenter
- 7.139 km S of Akutan, AlaskaMarch 22, 1957 · 100 km E of this epicenter
- 7.135 km SW of Nikolski, AlaskaMarch 11, 1957 · 171 km SW of this epicenter
- 7.0203 km SSE of Unalaska, AlaskaAugust 22, 1940 · 211 km SE of this epicenter
- 6.980 km SW of Nikolski, AlaskaMarch 9, 1957 · 215 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 · 295 km away · intensity VI
168 deaths$26 million damagetsunami
- 1965M6.5
Aleutian Islands: Fox Islands
2 Jul 1965 · 79 km away
Limited damage (under $1M)tsunami
- 1917M7.9
Alaska Peninsula
31 May 1917 · 168 km away · intensity V
- 1902M7.8
Aleutian Islands: Fox Islands
1 Jan 1902 · 148 km away
- 1907M7.8
Aleutian Islands
2 Sep 1907 · 206 km away
- 1916M7.5
Aleutian Islands: Fox Islands
18 Apr 1916 · 186 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.