Reviewed by USGSAlaska15y ago
M3.2 earthquake 122 km ESE of Atka, Alaska
Sunday, November 6, 2011, 09:20:52 UTC · 51.834°N, 172.510°W
A magnitude 3.2 earthquake struck 122 km ESE of Atka, Alaska on Sunday, November 6, 2011, 09:20:52 UTC, at a depth of 28.5 km (shallow).
- Magnitude
- 3.2
- Minor · ml
- Depth
- 29 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: 50 km aftershock search area
In context
How big was it, and why here?
Energy released
951 kg of TNT
That is about 1/15,825 of the Hiroshima bomb. A magnitude 5.0 releases about 501 times more energy.
Tectonic setting
83 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
29 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 50 km
USGS lists 4 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M3.2 on November 6, 2011. 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 847 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 · 218 km W of this epicenter
- 8.01986 Atka, Alaska EarthquakeMay 7, 1986 · 160 km W of this epicenter
- 7.8234 km SSW of Nikolski, AlaskaMarch 7, 1929 · 215 km SE of this epicenter
- 7.65 km WNW of Adak, AlaskaFebruary 14, 1905 · 288 km W of this epicenter
- 7.4133 km WNW of Nikolski, AlaskaApril 18, 1916 · 218 km NE of this epicenter
- 7.3Fox Islands, Aleutian Islands, AlaskaJune 24, 2011 · 52 km NE of this epicenter
- 7.158 km WNW of Atka, AlaskaFebruary 28, 1970 · 179 km NW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 12 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 · 218 km away
2 deathsSevere damage ($5–24M)tsunami
- 1986M8.0
Aleutian Islands: Adak
7 May 1986 · 160 km away · intensity VI
Moderate damage ($1–5M)tsunami
- 1901M7.8
Aleutian Islands: Fox Islands
31 Dec 1901 · 111 km away
Limited damage (under $1M)tsunami
- 1907M7.8
Aleutian Islands
2 Sep 1907 · 207 km away
- 1929M7.8
Aleutian Islands: Fox Islands
7 Mar 1929 · 197 km away · intensity V
tsunami
- 1916M7.5
Aleutian Islands: Fox Islands
18 Apr 1916 · 235 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.