M7.2 earthquake 2023 Sand Point, Alaska Earthquake

Sunday, July 16, 2023, 06:48:21 UTC · 54.393°N, 160.762°W

A magnitude 7.2 earthquake struck 2023 Sand Point, Alaska Earthquake on Sunday, July 16, 2023, 06:48:21 UTC, at a depth of 25.0 km (shallow). USGS received 165 “Did You Feel It?” reports, with a maximum reported intensity of VII (very strong). The USGS PAGER alert is green: low likelihood of casualties and damage. It is the strongest earthquake within 300 km since an M8.2 on July 29, 2021.

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: 7.2; Major · mww
Depth: 25 km; Shallow
Felt reports: 165; Max intensity VII
Est. shaking: VII; Very strong (ShakeMap)
PAGER alert: Green; Impact estimate
Tsunami: Flag; Check tsunami.gov

Outlined circle: this earthquakeDashed circle: 200 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)

In context

How big was it, and why here?

Energy released

951 kilotons of TNT

That is about 63 times the Hiroshima bomb. It released about 1,995 times the energy of a magnitude 5.0.

Tectonic setting

80 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

25 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
99603<br>0.190	II · Weak	22	816 km
99661<br>0.218	VII · Very strong	16	101 km
99669<br>0.242	II · Weak	12	891 km
99611<br>0.255	II · Weak	10	938 km
99612<br>0.262	V · Moderate	9	133 km
99516<br>0.262	II · Weak	9	993 km
99501<br>0.277	II · Weak	7	998 km
99577<br>0.293	II · Weak	5	1021 km
99685<br>0.293	II · Weak	5	394 km
99664<br>0.293	I · Not felt	5	960 km
99515<br>0.302	II · Weak	4	989 km
99507<br>0.302	I · Not felt	4	997 km

I felt it — report to USGS ↗

USGS PAGER estimate

Who was exposed to shaking

Modelled from the ShakeMap and population data. Alert level green: low likelihood of casualties and damage.

VI · Strong shaking: 1,700 people
V · Moderate shaking: 1,100 people

Estimated shaking in nearby towns

Sand PointPopulation 976VI · Strong

After the main event

Aftershocks within 200 km

USGS lists 148 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M5.8 on July 16, 2023. 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 393 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, which together caused about 169 recorded deaths. The most severe:

1946M8.6
Unimak Island
1 Apr 1946 · 168 km away · intensity VI
168 deaths$26 million damagetsunami
2023M7.2
Alaska Peninsula
16 Jul 2023 · 7 km away · intensity VI
1 deathtsunami
2020M7.8
Alaska
22 Jul 2020 · 158 km away · intensity VII
Limited damage (under $1M)tsunami
1938M8.2
Alaska
10 Nov 1938 · 195 km away · intensity VI
tsunami
2021M8.2
Alaska Peninsula
29 Jul 2021 · 214 km away · intensity VIII
tsunami
1788M8.0
Alaska Peninsula
6 Aug 1788 · 69 km away
tsunami

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

Nearby trackers