Reviewed by USGSAlaska11y ago
M2.5 earthquake 265 km W of Adak, Alaska
Tuesday, September 22, 2015, 01:00:14 UTC · 52.357°N, 179.564°E
A magnitude 2.5 earthquake struck 265 km W of Adak, Alaska on Tuesday, September 22, 2015, 01:00:14 UTC, at a depth of 98.7 km (intermediate).
- Magnitude
- 2.5
- Minor · ml
- Depth
- 99 km
- Intermediate
- Felt reports
- 0
- Max intensity I
- 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
85 kg of TNT
That is about 1/177,558 of the Hiroshima bomb. A magnitude 5.0 releases about 5,623 times more energy.
Tectonic setting
201 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
99 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 has not published any M2.5+ earthquake within 50 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 961 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.71965 Western Aleutian Islands (Hawadax/Rat Islands) EarthquakeFebruary 4, 1965 · 136 km SW of this epicenter
- 8.31906 Western Aleutian Islands (Hawadax/Rat Islands) EarthquakeAugust 17, 1906 · 110 km SW of this epicenter
- 7.977 km WSW of Adak, AlaskaJune 10, 1996 · 211 km SE of this epicenter
- 7.9Rat Islands, Aleutian Islands, AlaskaJune 23, 2014 · 80 km SW of this epicenter
- 7.8Rat Islands, Aleutian Islands, AlaskaNovember 17, 2003 · 149 km SW of this epicenter
- 7.6Rat Islands, Aleutian Islands, AlaskaMarch 30, 1965 · 258 km SW of this epicenter
- 7.65 km WNW of Adak, AlaskaFebruary 14, 1905 · 260 km E of this epicenter
- 7.4265 km WSW of Adak, AlaskaFebruary 4, 1965 · 102 km S 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. The most severe:
- 1965M8.7
Aleutian Islands: Rat Islands
4 Feb 1965 · 136 km away · intensity VI
Under $1 million damagetsunami
- 1906M8.3
Aleutian Islands: Rat Islands
17 Aug 1906 · 110 km away
- 1905M7.9
Andreanof Islands
14 Feb 1905 · 223 km away
- 1996M7.9
Andreanof Islands
10 Jun 1996 · 211 km away · intensity VI
tsunami
- 2014M7.9
Aleutian Islands
23 Jun 2014 · 80 km away · intensity VI
tsunami
- 2003M7.8
Aleutian Islands: Rat Islands
17 Nov 2003 · 149 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.