Reviewed by USGSAlaska10y ago
M2.5 earthquake 137 km SE of Atka, Alaska
Sunday, January 24, 2016, 00:19:25 UTC · 51.447°N, 172.608°W
A magnitude 2.5 earthquake struck 137 km SE of Atka, Alaska on Sunday, January 24, 2016, 00:19:25 UTC, at a depth of 33.0 km (shallow).
- Magnitude
- 2.5
- Minor · ml
- Depth
- 33 km
- Shallow
- Felt reports
- 0
- Max intensity I
- 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
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
43 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
33 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 2 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M2.8 on February 15, 2016. 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 931 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 · 209 km W of this epicenter
- 8.01986 Atka, Alaska EarthquakeMay 7, 1986 · 150 km W of this epicenter
- 7.8234 km SSW of Nikolski, AlaskaMarch 7, 1929 · 206 km E of this epicenter
- 7.65 km WNW of Adak, AlaskaFebruary 14, 1905 · 287 km W of this epicenter
- 7.4133 km WNW of Nikolski, AlaskaApril 18, 1916 · 258 km NE of this epicenter
- 7.346 km SSW of Adak, AlaskaJune 10, 1996 · 294 km W of this epicenter
- 7.3Fox Islands, Aleutian Islands, AlaskaJune 24, 2011 · 86 km NE of this epicenter
- 7.175 km S of Adak, AlaskaMarch 14, 1957 · 288 km W of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 13 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 · 209 km away
2 deathsSevere damage ($5–24M)tsunami
- 1986M8.0
Aleutian Islands: Adak
7 May 1986 · 150 km away · intensity VI
Moderate damage ($1–5M)tsunami
- 1901M7.8
Aleutian Islands: Fox Islands
31 Dec 1901 · 110 km away
Limited damage (under $1M)tsunami
- 1907M7.8
Aleutian Islands
2 Sep 1907 · 234 km away
- 1929M7.8
Aleutian Islands: Fox Islands
7 Mar 1929 · 188 km away · intensity V
tsunami
- 1916M7.5
Aleutian Islands: Fox Islands
18 Apr 1916 · 272 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.