Reviewed by USGSAlaska89y ago
M6.9 earthquake 105 km ESE of Perryville, Alaska
Thursday, November 17, 1938, 03:54:41 UTC · 55.407°N, 157.730°W
A magnitude 6.9 earthquake struck 105 km ESE of Perryville, Alaska on Thursday, November 17, 1938, 03:54:41 UTC, at a depth of 35.0 km (shallow). It is the strongest earthquake within 300 km since an M8.2 on November 10, 1938.
- Magnitude
- 6.9
- Strong · mw
- Depth
- 35 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
338 kilotons of TNT
That is about 22 times the Hiroshima bomb. It released about 708 times the energy of a magnitude 5.0.
Tectonic setting
127 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
35 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 has not published any M2.5+ earthquake within 100 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 33 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 · 38 km SW of this epicenter
- 7.454 km SE of Sand Point, AlaskaMay 31, 1917 · 144 km W of this epicenter
- 7.0113 km ESE of Chignik, AlaskaMay 4, 1923 · 77 km NE of this epicenter
- 6.873 km SW of Sand Point, AlaskaJuly 2, 1922 · 231 km W of this epicenter
- 6.768 km SSE of King Cove, AlaskaApril 29, 1937 · 277 km W of this epicenter
- 6.6128 km SE of Chignik, AlaskaJuly 28, 1934 · 68 km E of this epicenter
- 6.672 km SE of Sand Point, AlaskaOctober 16, 1932 · 130 km SW of this epicenter
- 6.6104 km SSE of Perryville, AlaskaNovember 11, 1938 · 72 km SW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 6 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1938M8.2
Alaska
10 Nov 1938 · 41 km away · intensity VI
tsunami
- 1788M8.0
Alaska Peninsula
6 Aug 1788 · 212 km away
tsunami
- 1906M7.6
Aleutian Islands
23 Dec 1906 · 286 km away
- 1912M7.5
Alaska Peninsula
7 Nov 1912 · 287 km away · intensity V
- 1868
Alaska Peninsula
15 May 1868 · 212 km away
tsunami
- 1880
Alaska Peninsula
29 Sep 1880 · 141 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.