Reviewed by USGSAlaska70y ago
M5.8 earthquake 174 km SSE of Atka, Alaska
Monday, April 1, 1957, 11:35:35 UTC · 50.794°N, 173.084°W
A magnitude 5.8 earthquake struck 174 km SSE of Atka, Alaska on Monday, April 1, 1957, 11:35:35 UTC, at a depth of 20.0 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
- 20 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
9 kilotons of TNT
That is about 1/2 of the Hiroshima bomb. It released about 19 times the energy of a magnitude 5.0.
Tectonic setting
21 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
20 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 3 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M5.8 on April 2, 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 83 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 · 194 km NW of this epicenter
- 7.8234 km SSW of Nikolski, AlaskaMarch 7, 1929 · 232 km E of this epicenter
- 7.65 km WNW of Adak, AlaskaFebruary 14, 1905 · 279 km NW of this epicenter
- 7.175 km S of Adak, AlaskaMarch 14, 1957 · 259 km W of this epicenter
- 7.160 km SW of Adak, AlaskaMarch 12, 1957 · 300 km W of this epicenter
- 7.0101 km S of Adak, AlaskaSeptember 9, 1910 · 230 km W of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 4 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 · 194 km away
2 deathsSevere damage ($5–24M)tsunami
- 1901M7.8
Aleutian Islands: Fox Islands
31 Dec 1901 · 161 km away
Limited damage (under $1M)tsunami
- 1929M7.8
Aleutian Islands: Fox Islands
7 Mar 1929 · 217 km away · intensity V
tsunami
- 1946
East Aleutian Islands
1 Nov 1946 · 126 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.