QuakeScout
Magnitude4.4

Reviewed by USGSAlaska2y ago

M4.4 earthquake 117 km E of Nikolski, Alaska

Saturday, May 18, 2024, 23:27:44 UTC · 52.768°N, 167.135°W

A magnitude 4.4 earthquake struck 117 km E of Nikolski, Alaska on Saturday, May 18, 2024, 23:27:44 UTC, at a depth of 40.2 km (shallow).

Magnitude
4.4
Light · mb
Depth
40 km
Shallow
Felt reports
0
Did You Feel It?
Est. shaking
II
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

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

60 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

40 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 M2.8 on June 2, 2024. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

M3M41h6h1d3d7d14d30dMainshock M4.4
Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.
  1. 2.8106 km S of Unalaska, Alaska2y ago · 28 km NE of this epicenter
  2. 2.8125 km ESE of Nikolski, Alaska2y ago · 30 km S of this epicenter
  3. 2.5110 km SSW of Unalaska, Alaska2y ago · 19 km N of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 705 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

  1. 8.6The 1946 Unimak Island, Alaska EarthquakeApril 1, 1946 · 298 km E of this epicenter
  2. 7.8234 km SSW of Nikolski, AlaskaMarch 7, 1929 · 276 km SW of this epicenter
  3. 7.881 km E of Nikolski, AlaskaJuly 2, 1965 · 44 km NW of this epicenter
  4. 7.4133 km WNW of Nikolski, AlaskaApril 18, 1916 · 247 km W of this epicenter
  5. 7.139 km S of Akutan, AlaskaMarch 22, 1957 · 144 km NE of this epicenter
  6. 7.135 km SW of Nikolski, AlaskaMarch 11, 1957 · 139 km W of this epicenter
  7. 7.0203 km SSE of Unalaska, AlaskaAugust 22, 1940 · 130 km SE of this epicenter

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 13 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 168 recorded deaths. The most severe:

  1. 1946M8.6

    Unimak Island

    1 Apr 1946 · 298 km away · intensity VI

    168 deaths$26 million damagetsunami

  2. 1965M6.5

    Aleutian Islands: Fox Islands

    2 Jul 1965 · 40 km away

    Limited damage (under $1M)tsunami

  3. 1917M7.9

    Alaska Peninsula

    31 May 1917 · 260 km away · intensity V

  4. 1902M7.8

    Aleutian Islands: Fox Islands

    1 Jan 1902 · 48 km away

  5. 1907M7.8

    Aleutian Islands

    2 Sep 1907 · 176 km away

  6. 1929M7.8

    Aleutian Islands: Fox Islands

    7 Mar 1929 · 278 km away · intensity V

    tsunami

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

Nearby trackers

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