Reviewed by USGSAlaska3y ago
M2.6 earthquake 54 km ESE of False Pass, Alaska
Wednesday, October 11, 2023, 05:56:05 UTC · 54.592°N, 162.699°W
A magnitude 2.6 earthquake struck 54 km ESE of False Pass, Alaska on Wednesday, October 11, 2023, 05:56:05 UTC, at a depth of 9.0 km (shallow).
- Magnitude
- 2.6
- 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
120 kg of TNT
That is about 1/125,702 of the Hiroshima bomb. A magnitude 5.0 releases about 3,981 times more energy.
Tectonic setting
135 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: 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 4 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M3.1 on October 19, 2023. 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 392 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 · 123 km S of this epicenter
- 8.21938 Semidi Islands, Alaska EarthquakeNovember 10, 1938 · 296 km E of this epicenter
- 7.82020 Perryville, Alaska EarthquakeJuly 22, 2020 · 268 km E of this epicenter
- 7.62020 Sand Point, Alaska EarthquakeOctober 19, 2020 · 198 km E of this epicenter
- 7.454 km SE of Sand Point, AlaskaMay 31, 1917 · 186 km E of this epicenter
- 7.22023 Sand Point, Alaska EarthquakeJuly 16, 2023 · 127 km E of this epicenter
- 7.190 km SE of King Cove, AlaskaMay 14, 1948 · 99 km E of this epicenter
- 7.139 km S of Akutan, AlaskaMarch 22, 1957 · 219 km SW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 11 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 · 123 km away · intensity VI
168 deaths$26 million damagetsunami
- 2023M7.2
Alaska Peninsula
16 Jul 2023 · 126 km away · intensity VI
1 deathtsunami
- 2020M7.8
Alaska
22 Jul 2020 · 268 km away · intensity VII
Limited damage (under $1M)tsunami
- 1938M8.2
Alaska
10 Nov 1938 · 293 km away · intensity VI
tsunami
- 1788M8.0
Alaska Peninsula
6 Aug 1788 · 118 km away
tsunami
- 2020M7.6
Alaska
19 Oct 2020 · 198 km away · intensity IX
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.