Reviewed by USGSAlaska4y ago
M2.8 earthquake 204 km SSW of Akhiok, Alaska
Tuesday, November 9, 2021, 08:43:36 UTC · 55.172°N, 155.000°W
A magnitude 2.8 earthquake struck 204 km SSW of Akhiok, Alaska on Tuesday, November 9, 2021, 08:43:36 UTC, at a depth of 19.2 km (shallow).
- Magnitude
- 2.8
- Minor · ml
- Depth
- 19 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- —
- No ShakeMap
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquake
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
26 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
19 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
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 has not published any M2.5+ earthquake within 50 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 311 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.21938 Semidi Islands, Alaska EarthquakeNovember 10, 1938 · 202 km W of this epicenter
- 8.22021 Chignik, Alaska EarthquakeJuly 29, 2021 · 184 km W of this epicenter
- 7.82020 Perryville, Alaska EarthquakeJuly 22, 2020 · 229 km W of this epicenter
- 7.14 km ENE of Karluk, AlaskaNovember 7, 1912 · 272 km N of this epicenter
- 7.0113 km ESE of Chignik, AlaskaMay 4, 1923 · 134 km NW of this epicenter
- 7.026 km SSE of Karluk, AlaskaDecember 6, 1999 · 245 km N of this epicenter
- 7.0164 km SE of Chignik, AlaskaSeptember 4, 1989 · 92 km W of this epicenter
- 6.9112 km E of Chignik, AlaskaOctober 11, 2021 · 159 km NW of this epicenter
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. The most severe:
- 1900M8.3
Kodiak Island
9 Oct 1900 · 233 km away · intensity VIII
Limited damage (under $1M)
- 1788M8.0
Unga Island
21 Jul 1788 · 238 km away · intensity VII
Limited damage (under $1M)tsunami
- 2020M7.8
Alaska
22 Jul 2020 · 229 km away · intensity VII
Limited damage (under $1M)tsunami
- 1970M6.0
Andreanof Islands
11 Mar 1970 · 268 km away · intensity V
Limited damage (under $1M)tsunami
- 1792
Kodiak Island
1792 · 276 km away · intensity VII
Limited damage (under $1M)tsunami
- 1938M8.2
Alaska
10 Nov 1938 · 216 km away · intensity VI
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.