Reviewed by USGSAlaska79y ago
M6.1 earthquake 39 km SW of Sand Point, Alaska
Monday, May 17, 1948, 17:48:40 UTC · 55.134°N, 161.015°W
A magnitude 6.1 earthquake struck 39 km SW of Sand Point, Alaska on Monday, May 17, 1948, 17:48:40 UTC, at a depth of 46.4 km (shallow). It is the strongest earthquake within 300 km since an M7.1 on May 14, 1948.
- Magnitude
- 6.1
- Strong · mw
- Depth
- 46 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
20 kilotons of TNT
That is about the energy of the Hiroshima bomb. It released about 42 times the energy of a magnitude 5.0.
Tectonic setting
163 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
46 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 56 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 · 217 km SW of this epicenter
- 8.21938 Semidi Islands, Alaska EarthquakeNovember 10, 1938 · 180 km E of this epicenter
- 7.454 km SE of Sand Point, AlaskaMay 31, 1917 · 74 km E of this epicenter
- 7.190 km SE of King Cove, AlaskaMay 14, 1948 · 61 km S of this epicenter
- 7.0113 km ESE of Chignik, AlaskaMay 4, 1923 · 279 km E of this epicenter
- 6.9105 km ESE of Perryville, AlaskaNovember 17, 1938 · 210 km E of this epicenter
- 6.873 km SW of Sand Point, AlaskaJuly 2, 1922 · 37 km S of this epicenter
- 6.768 km SSE of King Cove, AlaskaApril 29, 1937 · 84 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, which together caused about 168 recorded deaths. The most severe:
- 1946M8.6
Unimak Island
1 Apr 1946 · 217 km away · intensity VI
168 deaths$26 million damagetsunami
- 1938M8.2
Alaska
10 Nov 1938 · 172 km away · intensity VI
tsunami
- 1788M8.0
Alaska Peninsula
6 Aug 1788 · 15 km away
tsunami
- 1948M7.5
Alaska Peninsula
14 May 1948 · 71 km away
- 1820
East Aleutian Islands
1 Mar 1820 · 243 km away
tsunami
- 1868
Alaska Peninsula
15 May 1868 · 15 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.