Reviewed by USGSAlaska70y ago
M6.7 earthquake 120 km S of Akhiok, Alaska
Wednesday, April 10, 1957, 11:30:03 UTC · 55.869°N, 153.964°W
A magnitude 6.7 earthquake struck 120 km S of Akhiok, Alaska on Wednesday, April 10, 1957, 11:30:03 UTC, at a depth of 15.0 km (shallow). It is the strongest earthquake within 300 km since an M6.9 on February 13, 1951.
- Magnitude
- 6.7
- Strong · mw
- Depth
- 15 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
181 kilotons of TNT
That is about 12 times the Hiroshima bomb. It released about 380 times the energy of a magnitude 5.0.
Tectonic setting
51 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
15 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 100 km
USGS has not published any M2.5+ earthquake within 100 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:
- 8.21938 Semidi Islands, Alaska EarthquakeNovember 10, 1938 · 276 km W of this epicenter
- 7.9Kodiak Island region, AlaskaOctober 9, 1900 · 249 km NE of this epicenter
- 7.14 km ENE of Karluk, AlaskaNovember 7, 1912 · 193 km N of this epicenter
- 7.0113 km ESE of Chignik, AlaskaMay 4, 1923 · 175 km W of this epicenter
- 6.9105 km ESE of Perryville, AlaskaNovember 17, 1938 · 242 km W of this epicenter
- 6.9143 km ESE of Chignik, AlaskaFebruary 13, 1951 · 145 km W of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 9 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1900M8.3
Kodiak Island
9 Oct 1900 · 139 km away · intensity VIII
Limited damage (under $1M)
- 1788M8.0
Unga Island
21 Jul 1788 · 139 km away · intensity VII
Limited damage (under $1M)tsunami
- 1792
Kodiak Island
1792 · 174 km away · intensity VII
Limited damage (under $1M)tsunami
- 1938M8.2
Alaska
10 Nov 1938 · 280 km away · intensity VI
tsunami
- 1906M7.6
Aleutian Islands
23 Dec 1906 · 109 km away
- 1912M7.5
Alaska Peninsula
7 Nov 1912 · 192 km away · intensity V
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.