Reviewed by USGSAlaska70y ago
M6.1 earthquake 207 km ESE of Atka, Alaska
Wednesday, March 13, 1957, 02:48:27 UTC · 51.657°N, 171.314°W
A magnitude 6.1 earthquake struck 207 km ESE of Atka, Alaska on Wednesday, March 13, 1957, 02:48:27 UTC, at a depth of 35.0 km (shallow). It is the strongest earthquake within 300 km since an M6.5 on March 12, 1957.
- Magnitude
- 6.1
- Strong · 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: 100 km aftershock search area
In context
How big was it, and why here?
Energy released
19 kilotons of TNT
That is about the energy of the Hiroshima bomb. It released about 39 times the energy of a magnitude 5.0.
Tectonic setting
45 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 100 km
USGS lists 4 M2.5+ earthquakes within 100 km in the following 30 days; the largest was M6.3 on April 5, 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 89 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 · 298 km W of this epicenter
- 7.8234 km SSW of Nikolski, AlaskaMarch 7, 1929 · 135 km SE of this epicenter
- 7.4133 km WNW of Nikolski, AlaskaApril 18, 1916 · 203 km N of this epicenter
- 7.135 km SW of Nikolski, AlaskaMarch 11, 1957 · 185 km NE of this epicenter
- 6.980 km SW of Nikolski, AlaskaMarch 9, 1957 · 143 km NE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 8 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 · 298 km away
2 deathsSevere damage ($5–24M)tsunami
- 1901M7.8
Aleutian Islands: Fox Islands
31 Dec 1901 · 31 km away
Limited damage (under $1M)tsunami
- 1902M7.8
Aleutian Islands: Fox Islands
1 Jan 1902 · 274 km away
- 1907M7.8
Aleutian Islands
2 Sep 1907 · 150 km away
- 1929M7.8
Aleutian Islands: Fox Islands
7 Mar 1929 · 117 km away · intensity V
tsunami
- 1916M7.5
Aleutian Islands: Fox Islands
18 Apr 1916 · 203 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.