Reviewed by USGSAlaska72y ago
M6.8 earthquake 81 km ENE of Nikolski, Alaska
Thursday, January 13, 1955, 02:03:48 UTC · 53.141°N, 167.701°W
A magnitude 6.8 earthquake struck 81 km ENE of Nikolski, Alaska on Thursday, January 13, 1955, 02:03:48 UTC, at a depth of 17.6 km (shallow). It is the strongest earthquake within 300 km since an M7.0 on August 22, 1940.
- Magnitude
- 6.8
- Strong · mw
- Depth
- 18 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: 100 km aftershock search area
In context
How big was it, and why here?
Energy released
256 kilotons of TNT
That is about 17 times the Hiroshima bomb. It released about 537 times the energy of a magnitude 5.0.
Tectonic setting
112 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
18 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 100 km
USGS lists 1 M2.5+ earthquake within 100 km in the following 30 days; the largest was M6.5 on January 13, 1955. 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 67 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.8234 km SSW of Nikolski, AlaskaMarch 7, 1929 · 287 km SW of this epicenter
- 7.4133 km WNW of Nikolski, AlaskaApril 18, 1916 · 200 km W of this epicenter
- 7.0203 km SSE of Unalaska, AlaskaAugust 22, 1940 · 184 km SE of this epicenter
- 6.977 km SSW of Nikolski, AlaskaJanuary 23, 1935 · 147 km SW of this epicenter
- 6.846 km SSW of Nikolski, AlaskaJuly 22, 1933 · 120 km SW of this epicenter
- 6.7103 km SE of Nikolski, AlaskaFebruary 20, 1916 · 83 km S 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:
- 1901M7.8
Aleutian Islands: Fox Islands
31 Dec 1901 · 294 km away
Limited damage (under $1M)tsunami
- 1917M7.9
Alaska Peninsula
31 May 1917 · 206 km away · intensity V
- 1902M7.8
Aleutian Islands: Fox Islands
1 Jan 1902 · 83 km away
- 1907M7.8
Aleutian Islands
2 Sep 1907 · 149 km away
- 1929M7.8
Aleutian Islands: Fox Islands
7 Mar 1929 · 285 km away · intensity V
tsunami
- 1916M7.5
Aleutian Islands: Fox Islands
18 Apr 1916 · 154 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.