Reviewed by USGSAlaska10y ago
M3.8 earthquake 31 km NE of Nikolski, Alaska
Tuesday, March 22, 2016, 10:04:20 UTC · 53.144°N, 168.544°W
A magnitude 3.8 earthquake struck 31 km NE of Nikolski, Alaska on Tuesday, March 22, 2016, 10:04:20 UTC, at a depth of 105.8 km (intermediate).
- Magnitude
- 3.8
- Minor · ml
- Depth
- 106 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 earthquakeDashed circle: 50 km aftershock search area
In context
How big was it, and why here?
Energy released
8 tons of TNT
That is about 1/1,992 of the Hiroshima bomb. A magnitude 5.0 releases about 63 times more energy.
Tectonic setting
132 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
106 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 M2.7 on April 9, 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 615 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 · 263 km S of this epicenter
- 7.881 km E of Nikolski, AlaskaJuly 2, 1965 · 61 km E of this epicenter
- 7.4133 km WNW of Nikolski, AlaskaApril 18, 1916 · 145 km W of this epicenter
- 7.3Fox Islands, Aleutian Islands, AlaskaJune 24, 2011 · 253 km SW of this epicenter
- 7.139 km S of Akutan, AlaskaMarch 22, 1957 · 197 km E of this epicenter
- 7.135 km SW of Nikolski, AlaskaMarch 11, 1957 · 66 km SW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 15 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 · 253 km away
Limited damage (under $1M)tsunami
- 1965M6.5
Aleutian Islands: Fox Islands
2 Jul 1965 · 68 km away
Limited damage (under $1M)tsunami
- 1917M7.9
Alaska Peninsula
31 May 1917 · 187 km away · intensity V
- 1902M7.8
Aleutian Islands: Fox Islands
1 Jan 1902 · 109 km away
- 1907M7.8
Aleutian Islands
2 Sep 1907 · 101 km away
- 1929M7.8
Aleutian Islands: Fox Islands
7 Mar 1929 · 258 km away · intensity V
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.