Reviewed by USGSAlaska5d ago
M3.6 earthquake 167 km WSW of Nikolski, Alaska
Monday, September 21, 2026, 10:00:11 UTC · 52.182°N, 171.004°W
A magnitude 3.6 earthquake struck 167 km WSW of Nikolski, Alaska on Monday, September 21, 2026, 10:00:11 UTC, at a depth of 105.6 km (intermediate).
- Magnitude
- 3.6
- Minor · ml
- Depth
- 106 km
- Intermediate
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- I
- Not felt (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
4 tons of TNT
That is about 1/3,975 of the Hiroshima bomb. A magnitude 5.0 releases about 126 times more energy.
Tectonic setting
95 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: 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 since this event; the largest was M3.9 on September 22, 2026. 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 954 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.01986 Atka, Alaska EarthquakeMay 7, 1986 · 269 km W of this epicenter
- 7.8234 km SSW of Nikolski, AlaskaMarch 7, 1929 · 165 km SE of this epicenter
- 7.881 km E of Nikolski, AlaskaJuly 2, 1965 · 244 km NE of this epicenter
- 7.4133 km WNW of Nikolski, AlaskaApril 18, 1916 · 142 km N of this epicenter
- 7.3Fox Islands, Aleutian Islands, AlaskaJune 24, 2011 · 59 km W of this epicenter
- 7.158 km WNW of Atka, AlaskaFebruary 28, 1970 · 268 km W of this epicenter
- 7.135 km SW of Nikolski, AlaskaMarch 11, 1957 · 135 km NE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 14 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1986M8.0
Aleutian Islands: Adak
7 May 1986 · 269 km away · intensity VI
Moderate damage ($1–5M)tsunami
- 1901M7.8
Aleutian Islands: Fox Islands
31 Dec 1901 · 81 km away
Limited damage (under $1M)tsunami
- 1965M6.5
Aleutian Islands: Fox Islands
2 Jul 1965 · 252 km away
Limited damage (under $1M)tsunami
- 1902M7.8
Aleutian Islands: Fox Islands
1 Jan 1902 · 240 km away
- 1907M7.8
Aleutian Islands
2 Sep 1907 · 98 km away
- 1929M7.8
Aleutian Islands: Fox Islands
7 Mar 1929 · 149 km away · intensity V
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.