Reviewed by USGSAlaska18y ago
M2.6 earthquake 66 km ENE of Adak, Alaska
Thursday, September 25, 2008, 21:38:36 UTC · 52.074°N, 175.718°W
A magnitude 2.6 earthquake struck 66 km ENE of Adak, Alaska on Thursday, September 25, 2008, 21:38:36 UTC, at a depth of 159.9 km (intermediate).
- Magnitude
- 2.6
- Minor · ml
- Depth
- 160 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
120 kg of TNT
That is about 1/125,702 of the Hiroshima bomb. A magnitude 5.0 releases about 3,981 times more energy.
Tectonic setting
146 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
160 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 3 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M4.9 on September 26, 2008. 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 953 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 · 64 km S of this epicenter
- 8.01986 Atka, Alaska EarthquakeMay 7, 1986 · 89 km SE of this epicenter
- 7.977 km WSW of Adak, AlaskaJune 10, 1996 · 143 km SW of this epicenter
- 7.65 km WNW of Adak, AlaskaFebruary 14, 1905 · 70 km W of this epicenter
- 7.388 km WSW of Adak, AlaskaJuly 7, 1929 · 154 km SW of this epicenter
- 7.346 km SSW of Adak, AlaskaJune 10, 1996 · 102 km SW of this epicenter
- 7.2207 km WSW of Adak, AlaskaDecember 19, 2007 · 273 km W of this epicenter
- 7.2162 km WSW of Adak, AlaskaMarch 16, 1957 · 229 km W 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 · 64 km away
2 deathsSevere damage ($5–24M)tsunami
- 1986M8.0
Aleutian Islands: Adak
7 May 1986 · 89 km away · intensity VI
Moderate damage ($1–5M)tsunami
- 1905M7.9
Andreanof Islands
14 Feb 1905 · 247 km away
- 1996M7.9
Andreanof Islands
10 Jun 1996 · 143 km away · intensity VI
tsunami
- 1996M7.3
Andreanof Islands
10 Jun 1996 · 102 km away
tsunami
- 1971M7.1
Andreanof Islands
2 May 1971 · 127 km away · intensity VI
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.