M6.5 earthquake 177 km W of Nikolski, Alaska

Thursday, September 17, 2026, 14:19:52 UTC · 52.956°N, 171.503°W

A magnitude 6.5 earthquake struck 177 km W of Nikolski, Alaska on Thursday, September 17, 2026, 14:19:52 UTC, at a depth of 98.0 km (intermediate). USGS received 8 “Did You Feel It?” reports, with a maximum reported intensity of III (weak). The USGS PAGER alert is green: low likelihood of casualties and damage. It is the strongest earthquake within 300 km since an M6.6 on January 11, 2022.

Tsunami flagUSGS sets this flag for large events in oceanic regions so tsunami warning centers review them. It does not by itself mean a tsunami occurred. Check tsunami.gov and local authorities for official messages.

Magnitude: 6.5; Strong · mww
Depth: 98 km; Intermediate
Felt reports: 8; Max intensity III
Est. shaking: V; Moderate (ShakeMap)
PAGER alert: Green; Impact estimate
Tsunami: Flag; Check tsunami.gov

Outlined circle: this earthquakeDashed circle: 100 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)

In context

How big was it, and why here?

Energy released

85 kilotons of TNT

That is about 6 times the Hiroshima bomb. It released about 178 times the energy of a magnitude 5.0.

Tectonic setting

186 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

98 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

Reports sent by people to USGS, grouped by place (most reports first). Intensity uses the Modified Mercalli scale (I–X): what people felt, not the magnitude.

Place	Intensity	Reports	Distance
99685<br>0.293	III · Weak	5	347 km
99546<br>0.320	III · Weak	2	388 km
99547<br>0.330	III · Weak	1	255 km

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 populated area was estimated to feel noticeable shaking.

After the main event

Aftershocks within 100 km

USGS lists 17 M2.5+ earthquakes within 100 km since this event; the largest was M4.6 on September 20, 2026. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.

Regional history

Past M5+ earthquakes within 300 km

USGS lists 922 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

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:

1986M8.0
Aleutian Islands: Adak
7 May 1986 · 274 km away · intensity VI
Moderate damage ($1–5M)tsunami
1901M7.8
Aleutian Islands: Fox Islands
31 Dec 1901 · 171 km away
Limited damage (under $1M)tsunami
1965M6.5
Aleutian Islands: Fox Islands
2 Jul 1965 · 265 km away
Limited damage (under $1M)tsunami
1917M7.9
Alaska Peninsula
31 May 1917 · 257 km away · intensity V
1902M7.8
Aleutian Islands: Fox Islands
1 Jan 1902 · 277 km away
1907M7.8
Aleutian Islands
2 Sep 1907 · 126 km away

NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.

Nearby trackers