Reviewed by USGSAlaska4y ago
M2.8 earthquake 31 km N of False Pass, Alaska
Monday, March 28, 2022, 21:53:26 UTC · 55.136°N, 163.451°W
A magnitude 2.8 earthquake struck 31 km N of False Pass, Alaska on Monday, March 28, 2022, 21:53:26 UTC, at a depth of 152.1 km (intermediate).
- Magnitude
- 2.8
- Minor · ml
- Depth
- 152 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
206 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
152 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 M2.9 on April 7, 2022. 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 375 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 · 187 km S of this epicenter
- 7.62020 Sand Point, Alaska EarthquakeOctober 19, 2020 · 252 km E of this epicenter
- 7.454 km SE of Sand Point, AlaskaMay 31, 1917 · 228 km E of this epicenter
- 7.190 km SE of King Cove, AlaskaMay 14, 1948 · 158 km E of this epicenter
- 7.139 km S of Akutan, AlaskaMarch 22, 1957 · 213 km SW of this epicenter
- 7.071 km SE of King Cove, AlaskaMay 30, 1991 · 134 km SE of this epicenter
- 6.917 km S of Sand Point, AlaskaMay 13, 1993 · 190 km E of this epicenter
- 6.873 km SW of Sand Point, AlaskaJuly 2, 1922 · 146 km E of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 8 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 · 187 km away · intensity VI
168 deaths$26 million damagetsunami
- 1788M8.0
Alaska Peninsula
6 Aug 1788 · 157 km away
tsunami
- 2020M7.6
Alaska
19 Oct 2020 · 252 km away · intensity IX
tsunami
- 1948M7.5
Alaska Peninsula
14 May 1948 · 172 km away
- 1957M7.5
Aleutian Islands: Fox Islands
22 Mar 1957 · 112 km away · intensity V
- 1820
East Aleutian Islands
1 Mar 1820 · 103 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.