M4.2 earthquake 92 km ENE of Nikolski, Alaska

Sunday, March 17, 2024, 01:45:45 UTC · 53.184°N, 167.549°W

A magnitude 4.2 earthquake struck 92 km ENE of Nikolski, Alaska on Sunday, March 17, 2024, 01:45:45 UTC, at a depth of 59.4 km (shallow). USGS received 1 “Did You Feel It?” report, with a maximum reported intensity of I (not felt).

Magnitude: 4.2; Light · mb
Depth: 59 km; Shallow
Felt reports: 1; Max intensity I
Est. shaking: III; Weak (ShakeMap)
PAGER alert: None; Not issued
Tsunami: No flag; USGS feed

Outlined circle: this earthquakeDashed circle: 50 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)

In context

How big was it, and why here?

Energy released

30 tons of TNT

That is about 1/500 of the Hiroshima bomb. A magnitude 5.0 releases about 16 times more energy.

Tectonic setting

113 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: shallow

59 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

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
99502<br>0.330	I · Not felt	1	1383 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 PAGER estimate is available for this event.

After the main event

Aftershocks within 50 km

USGS lists 7 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M4.4 on April 4, 2024. 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 703 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 12 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:

1965M6.5
Aleutian Islands: Fox Islands
2 Jul 1965 · 17 km away
Limited damage (under $1M)tsunami
1917M7.9
Alaska Peninsula
31 May 1917 · 206 km away · intensity V
1902M7.8
Aleutian Islands: Fox Islands
1 Jan 1902 · 87 km away
1907M7.8
Aleutian Islands
2 Sep 1907 · 161 km away
1929M7.8
Aleutian Islands: Fox Islands
7 Mar 1929 · 295 km away · intensity V
tsunami
1916M7.5
Aleutian Islands: Fox Islands
18 Apr 1916 · 164 km away

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

Nearby trackers