Reviewed by USGSAlaska10y ago
M2.5 earthquake 43 km WSW of Nikolski, Alaska
Sunday, May 15, 2016, 21:30:04 UTC · 52.789°N, 169.460°W
A magnitude 2.5 earthquake struck 43 km WSW of Nikolski, Alaska on Sunday, May 15, 2016, 21:30:04 UTC, at a depth of 80.8 km (intermediate).
- Magnitude
- 2.5
- Minor · ml
- Depth
- 81 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
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
120 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
81 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 M4.1 on May 16, 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 659 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.8234 km SSW of Nikolski, AlaskaMarch 7, 1929 · 211 km S of this epicenter
- 7.881 km E of Nikolski, AlaskaJuly 2, 1965 · 124 km E of this epicenter
- 7.4133 km WNW of Nikolski, AlaskaApril 18, 1916 · 108 km NW of this epicenter
- 7.3Fox Islands, Aleutian Islands, AlaskaJune 24, 2011 · 181 km SW of this epicenter
- 7.139 km S of Akutan, AlaskaMarch 22, 1957 · 269 km NE of this epicenter
- 7.135 km SW of Nikolski, AlaskaMarch 11, 1957 · 21 km SE 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. The most severe:
- 1901M7.8
Aleutian Islands: Fox Islands
31 Dec 1901 · 183 km away
Limited damage (under $1M)tsunami
- 1965M6.5
Aleutian Islands: Fox Islands
2 Jul 1965 · 131 km away
Limited damage (under $1M)tsunami
- 1917M7.9
Alaska Peninsula
31 May 1917 · 224 km away · intensity V
- 1902M7.8
Aleutian Islands: Fox Islands
1 Jan 1902 · 139 km away
- 1907M7.8
Aleutian Islands
2 Sep 1907 · 29 km away
- 1929M7.8
Aleutian Islands: Fox Islands
7 Mar 1929 · 202 km away · intensity V
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.