Reviewed by USGSAlaska10y ago
M4.4 earthquake 127 km SSW of Nikolski, Alaska
Friday, February 19, 2016, 06:06:36 UTC · 51.905°N, 169.671°W
A magnitude 4.4 earthquake struck 127 km SSW of Nikolski, Alaska on Friday, February 19, 2016, 06:06:36 UTC, at a depth of 22.0 km (shallow).
- Magnitude
- 4.4
- Light · mb
- Depth
- 22 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
60 tons of TNT
That is about 1/251 of the Hiroshima bomb. A magnitude 5.0 releases about 8 times more energy.
Tectonic setting
36 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
22 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 3 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M3.6 on February 26, 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 681 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 · 111 km S of this epicenter
- 7.881 km E of Nikolski, AlaskaJuly 2, 1965 · 184 km NE of this epicenter
- 7.4133 km WNW of Nikolski, AlaskaApril 18, 1916 · 184 km N of this epicenter
- 7.3Fox Islands, Aleutian Islands, AlaskaJune 24, 2011 · 149 km W of this epicenter
- 7.135 km SW of Nikolski, AlaskaMarch 11, 1957 · 93 km N of this epicenter
- 7.0203 km SSE of Unalaska, AlaskaAugust 22, 1940 · 287 km E 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:
- 1901M7.8
Aleutian Islands: Fox Islands
31 Dec 1901 · 106 km away
Limited damage (under $1M)tsunami
- 1965M6.5
Aleutian Islands: Fox Islands
2 Jul 1965 · 190 km away
Limited damage (under $1M)tsunami
- 1902M7.8
Aleutian Islands: Fox Islands
1 Jan 1902 · 158 km away
- 1907M7.8
Aleutian Islands
2 Sep 1907 · 76 km away
- 1929M7.8
Aleutian Islands: Fox Islands
7 Mar 1929 · 103 km away · intensity V
tsunami
- 1916M7.5
Aleutian Islands: Fox Islands
18 Apr 1916 · 157 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.