Reviewed by USGSAlaska70y ago
M5.9 earthquake in Andreanof Islands, Aleutian Islands, Alaska
Tuesday, April 9, 1957, 11:02:18 UTC · 51.035°N, 178.619°W
A magnitude 5.9 earthquake struck in Andreanof Islands, Aleutian Islands, Alaska on Tuesday, April 9, 1957, 11:02:18 UTC, at a depth of 35.0 km (shallow). It is the strongest earthquake within 300 km since an M6.8 on March 19, 1957.
- Magnitude
- 5.9
- Moderate · mw
- Depth
- 35 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: 75 km aftershock search area
In context
How big was it, and why here?
Energy released
11 kilotons of TNT
That is about the energy of the Hiroshima bomb. It released about 23 times the energy of a magnitude 5.0.
Tectonic setting
60 km
from the nearest mapped plate boundary, between the North American and Pacific plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
35 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 75 km
USGS lists 2 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M5.8 on April 15, 1957. 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 131 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.61957 Atka, Alaska EarthquakeMarch 9, 1957 · 215 km E of this epicenter
- 8.31906 Western Aleutian Islands (Hawadax/Rat Islands) EarthquakeAugust 17, 1906 · 240 km NW of this epicenter
- 7.65 km WNW of Adak, AlaskaFebruary 14, 1905 · 163 km NE of this epicenter
- 7.388 km WSW of Adak, AlaskaJuly 7, 1929 · 78 km NE of this epicenter
- 7.2238 km WSW of Adak, AlaskaMarch 22, 1905 · 87 km W of this epicenter
- 7.2162 km WSW of Adak, AlaskaMarch 16, 1957 · 46 km N of this epicenter
- 7.175 km S of Adak, AlaskaMarch 14, 1957 · 133 km E of this epicenter
- 7.160 km SW of Adak, AlaskaMarch 12, 1957 · 108 km NE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 5 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 2 recorded deaths. The most severe:
- 1957M8.6
Alaska
9 Mar 1957 · 215 km away
2 deathsSevere damage ($5–24M)tsunami
- 1906M8.3
Aleutian Islands: Rat Islands
17 Aug 1906 · 240 km away
- 1905M7.9
Andreanof Islands
14 Feb 1905 · 34 km away
- 1940M7.4
Aleutian Islands: Rat Islands
14 Jul 1940 · 245 km away
- 1946
East Aleutian Islands
1 Nov 1946 · 291 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.