M5.3 earthquake 67 km SSE of Akutan, Alaska

Monday, August 1, 2022, 00:36:40 UTC · 53.567°N, 165.420°W

A magnitude 5.3 earthquake struck 67 km SSE of Akutan, Alaska on Monday, August 1, 2022, 00:36:40 UTC, at a depth of 39.9 km (shallow). USGS received 5 “Did You Feel It?” reports, with a maximum reported intensity of IV (light). It is the strongest earthquake within 300 km since an M5.4 on February 3, 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: 5.3; Moderate · mww
Depth: 40 km; Shallow
Felt reports: 5; Max intensity IV
Est. shaking: III; Weak (ShakeMap)
PAGER alert: None; Not issued
Tsunami: Flag; Check tsunami.gov

Outlined circle: this earthquakeDashed circle: 75 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)

In context

How big was it, and why here?

Energy released

1 kilotons of TNT

That is about 1/11 of the Hiroshima bomb. It released about 3 times the energy of a magnitude 5.0.

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: 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

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>0.311	II · Weak	3	100 km
99553<br>0.330	IV · Light	1	80 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 75 km

USGS lists 10 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M4.6 on August 7, 2022. 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 565 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 10 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 168 recorded deaths. The most severe:

1946M8.6
Unimak Island
1 Apr 1946 · 171 km away · intensity VI
168 deaths$26 million damagetsunami
1965M6.5
Aleutian Islands: Fox Islands
2 Jul 1965 · 154 km away
Limited damage (under $1M)tsunami
1917M7.9
Alaska Peninsula
31 May 1917 · 277 km away · intensity V
1902M7.8
Aleutian Islands: Fox Islands
1 Jan 1902 · 190 km away
1957M7.5
Aleutian Islands: Fox Islands
22 Mar 1957 · 160 km away · intensity V
2015M6.9
Alaska
27 Jul 2015 · 300 km away · intensity IV
tsunami

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

Nearby trackers