Reviewed by USGSAlaska4y ago
M3.0 earthquake 203 km SE of Chignik, Alaska
Monday, November 1, 2021, 14:58:12 UTC · 54.894°N, 156.336°W
A magnitude 3.0 earthquake struck 203 km SE of Chignik, Alaska on Monday, November 1, 2021, 14:58:12 UTC, at a depth of 8.8 km (shallow).
- Magnitude
- 3.0
- Minor · ml
- Depth
- 9 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 earthquakeDashed circle: 50 km aftershock search area
In context
How big was it, and why here?
Energy released
477 kg of TNT
That is about 1/31,575 of the Hiroshima bomb. A magnitude 5.0 releases about 1,000 times more energy.
Tectonic setting
42 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
9 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 lists 7 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M3.8 on November 4, 2021. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
- 3.0195 km SE of Perryville, Alaska4y ago · 42 km SW of this epicenter
- 3.3197 km SE of Perryville, Alaska4y ago · 45 km SW of this epicenter
- 3.3193 km SE of Perryville, Alaska4y ago · 40 km SW of this epicenter
- 3.2204 km SE of Perryville, Alaska4y ago · 38 km SW of this epicenter
- 2.5156 km SE of Chignik, Alaska4y ago · 46 km NW of this epicenter
- 3.4212 km SE of Perryville, Alaska4y ago · 46 km SW of this epicenter
- 3.8213 km SE of Perryville, Alaska4y ago · 49 km SW of this epicenter
Regional history
Past M5+ earthquakes within 300 km
USGS lists 330 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 · 122 km W of this epicenter
- 8.22021 Chignik, Alaska EarthquakeJuly 29, 2021 · 112 km NW of this epicenter
- 7.82020 Perryville, Alaska EarthquakeJuly 22, 2020 · 146 km W of this epicenter
- 7.62020 Sand Point, Alaska EarthquakeOctober 19, 2020 · 214 km W of this epicenter
- 7.454 km SE of Sand Point, AlaskaMay 31, 1917 · 227 km W of this epicenter
- 7.0113 km ESE of Chignik, AlaskaMay 4, 1923 · 109 km N of this epicenter
- 7.026 km SSE of Karluk, AlaskaDecember 6, 1999 · 299 km NE of this epicenter
- 7.0164 km SE of Chignik, AlaskaSeptember 4, 1989 · 48 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 9 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 2020M7.8
Alaska
22 Jul 2020 · 146 km away · intensity VII
Limited damage (under $1M)tsunami
- 1938M8.2
Alaska
10 Nov 1938 · 145 km away · intensity VI
tsunami
- 2021M8.2
Alaska Peninsula
29 Jul 2021 · 107 km away · intensity VIII
tsunami
- 1788M8.0
Alaska Peninsula
6 Aug 1788 · 298 km away
tsunami
- 1906M7.6
Aleutian Islands
23 Dec 1906 · 265 km away
- 2020M7.6
Alaska
19 Oct 2020 · 214 km away · intensity IX
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.