Reviewed by USGSAlaska70y ago
M5.8 earthquake 220 km ESE of Atka, Alaska
Thursday, March 28, 1957, 20:08:25 UTC · 51.396°N, 171.284°W
A magnitude 5.8 earthquake struck 220 km ESE of Atka, Alaska on Thursday, March 28, 1957, 20:08:25 UTC, at a depth of 25.0 km (shallow). No earthquake of this size or larger appears within 300 km in the USGS catalog since 1900.
- Magnitude
- 5.8
- Moderate · mw
- Depth
- 25 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 earthquake
In context
How big was it, and why here?
Energy released
8 kilotons of TNT
That is about 1/2 of the Hiroshima bomb. It released about 17 times the energy of a magnitude 5.0.
Tectonic setting
17 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
25 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 has not published any M2.5+ earthquake within 75 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 89 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.8234 km SSW of Nikolski, AlaskaMarch 7, 1929 · 118 km SE of this epicenter
- 7.4133 km WNW of Nikolski, AlaskaApril 18, 1916 · 231 km N of this epicenter
- 7.135 km SW of Nikolski, AlaskaMarch 11, 1957 · 203 km NE of this epicenter
- 6.980 km SW of Nikolski, AlaskaMarch 9, 1957 · 160 km NE of this epicenter
- 6.9182 km SSE of Atka, AlaskaJanuary 27, 1906 · 124 km SW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 7 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1901M7.8
Aleutian Islands: Fox Islands
31 Dec 1901 · 19 km away
Limited damage (under $1M)tsunami
- 1902M7.8
Aleutian Islands: Fox Islands
1 Jan 1902 · 283 km away
- 1907M7.8
Aleutian Islands
2 Sep 1907 · 170 km away
- 1929M7.8
Aleutian Islands: Fox Islands
7 Mar 1929 · 100 km away · intensity V
tsunami
- 1916M7.5
Aleutian Islands: Fox Islands
18 Apr 1916 · 229 km away
- 1872
Aleutian Islands: Fox Islands
23 Aug 1872 · 211 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.