M5.3 earthquake 110 km SE of Perryville, Alaska

Sunday, February 20, 2022, 11:47:09 UTC · 55.273°N, 157.808°W

A magnitude 5.3 earthquake struck 110 km SE of Perryville, Alaska on Sunday, February 20, 2022, 11:47:09 UTC, at a depth of 16.5 km (shallow). USGS received 5 “Did You Feel It?” reports, with a maximum reported intensity of III (weak). 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 · ml
Depth: 17 km; Shallow
Felt reports: 5; Max intensity III
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

115 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

17 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
99648<br>0.330	III · Weak	1	117 km
99664<br>0.330	III · Weak	1	760 km
99676<br>0.330	III · Weak	1	895 km
99565<br>0.330	III · Weak	1	125 km
99564<br>0.330	II · Weak	1	122 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 8 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M3.5 on February 23, 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 341 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. The most severe:

2020M7.8
Alaska
22 Jul 2020 · 55 km away · intensity VII
Limited damage (under $1M)tsunami
1938M8.2
Alaska
10 Nov 1938 · 42 km away · intensity VI
tsunami
2021M8.2
Alaska Peninsula
29 Jul 2021 · 6 km away · intensity VIII
tsunami
1788M8.0
Alaska Peninsula
6 Aug 1788 · 205 km away
tsunami
1906M7.6
Aleutian Islands
23 Dec 1906 · 299 km away
2020M7.6
Alaska
19 Oct 2020 · 138 km away · intensity IX
tsunami

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

Nearby trackers