Reviewed by USGSAlaska5y ago
M2.8 earthquake 37 km NE of Sand Point, Alaska
Saturday, January 30, 2021, 05:14:52 UTC · 55.563°N, 160.055°W
A magnitude 2.8 earthquake struck 37 km NE of Sand Point, Alaska on Saturday, January 30, 2021, 05:14:52 UTC, at a depth of 80.2 km (intermediate).
- Magnitude
- 2.8
- Minor · ml
- Depth
- 80 km
- Intermediate
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- —
- No ShakeMap
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeDashed circle: 50 km aftershock search area
In context
How big was it, and why here?
Energy released
239 kg of TNT
That is about 1/63,000 of the Hiroshima bomb. A magnitude 5.0 releases about 1,995 times more energy.
Tectonic setting
193 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: intermediate
80 km
Intermediate-depth earthquakes usually break inside a plate that is sinking into the mantle. Shaking spreads over a wide area but is gentler at the epicenter than a shallow quake of the same size.
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 2 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M2.7 on February 7, 2021. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 294 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.6The 1946 Unimak Island, Alaska EarthquakeApril 1, 1946 · 292 km SW of this epicenter
- 8.21938 Semidi Islands, Alaska EarthquakeNovember 10, 1938 · 126 km E of this epicenter
- 7.82020 Perryville, Alaska EarthquakeJuly 22, 2020 · 107 km SE of this epicenter
- 7.62020 Sand Point, Alaska EarthquakeOctober 19, 2020 · 110 km S of this epicenter
- 7.454 km SE of Sand Point, AlaskaMay 31, 1917 · 64 km S of this epicenter
- 7.190 km SE of King Cove, AlaskaMay 14, 1948 · 129 km SW of this epicenter
- 7.0113 km ESE of Chignik, AlaskaMay 4, 1923 · 208 km E of this epicenter
- 7.071 km SE of King Cove, AlaskaMay 30, 1991 · 148 km SW of this epicenter
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 · 292 km away · intensity VI
168 deaths$26 million damagetsunami
- 2020M7.8
Alaska
22 Jul 2020 · 107 km away · intensity VII
Limited damage (under $1M)tsunami
- 1938M8.2
Alaska
10 Nov 1938 · 106 km away · intensity VI
tsunami
- 2021M8.2
Alaska Peninsula
29 Jul 2021 · 142 km away · intensity VIII
tsunami
- 1788M8.0
Alaska Peninsula
6 Aug 1788 · 87 km away
tsunami
- 2020M7.6
Alaska
19 Oct 2020 · 110 km away · intensity IX
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.