Reviewed by USGSAlaska14y ago
M2.7 earthquake 22 km ENE of Adak, Alaska
Saturday, March 10, 2012, 07:16:29 UTC · 51.958°N, 176.333°W
A magnitude 2.7 earthquake struck 22 km ENE of Adak, Alaska on Saturday, March 10, 2012, 07:16:29 UTC, at a depth of 86.0 km (intermediate).
- Magnitude
- 2.7
- Minor · ml
- Depth
- 86 km
- Intermediate
- 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
169 kg of TNT
That is about 1/88,990 of the Hiroshima bomb. A magnitude 5.0 releases about 2,818 times more energy.
Tectonic setting
143 km
from the nearest mapped plate boundary, between the North American and Pacific plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: intermediate
86 km
Intermediate-depth earthquakes usually break inside a plate that is sinking into the mantle. Shaking spreads over a wide area but is gentler at the epicenter than a shallow quake of the same size.
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 2 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M3.1 on April 5, 2012. 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 1,056 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 · 71 km SE of this epicenter
- 8.01986 Atka, Alaska EarthquakeMay 7, 1986 · 118 km SE of this epicenter
- 7.977 km WSW of Adak, AlaskaJune 10, 1996 · 100 km SW of this epicenter
- 7.65 km WNW of Adak, AlaskaFebruary 14, 1905 · 26 km W of this epicenter
- 7.4265 km WSW of Adak, AlaskaFebruary 4, 1965 · 287 km W of this epicenter
- 7.388 km WSW of Adak, AlaskaJuly 7, 1929 · 111 km SW of this epicenter
- 7.346 km SSW of Adak, AlaskaJune 10, 1996 · 64 km SW of this epicenter
- 7.2207 km WSW of Adak, AlaskaDecember 19, 2007 · 229 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, which together caused about 2 recorded deaths. The most severe:
- 1957M8.6
Alaska
9 Mar 1957 · 71 km away
2 deathsSevere damage ($5–24M)tsunami
- 1986M8.0
Aleutian Islands: Adak
7 May 1986 · 118 km away · intensity VI
Moderate damage ($1–5M)tsunami
- 1905M7.9
Andreanof Islands
14 Feb 1905 · 206 km away
- 1996M7.9
Andreanof Islands
10 Jun 1996 · 100 km away · intensity VI
tsunami
- 1996M7.3
Andreanof Islands
10 Jun 1996 · 64 km away
tsunami
- 1971M7.1
Andreanof Islands
2 May 1971 · 86 km away · intensity VI
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.