Reviewed by USGSAlaska62y ago
M7.6 earthquake in Rat Islands, Aleutian Islands, Alaska
Tuesday, March 30, 1965, 02:27:06 UTC · 50.286°N, 177.877°E
A magnitude 7.6 earthquake struck in Rat Islands, Aleutian Islands, Alaska on Tuesday, March 30, 1965, 02:27:06 UTC, at a depth of 23.5 km (shallow). It is the strongest earthquake within 300 km since an M8.7 on February 4, 1965.
- Magnitude
- 7.6
- Major · mw
- Depth
- 24 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- V
- Moderate (ShakeMap)
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeDashed circle: 200 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)
In context
How big was it, and why here?
Energy released
3.8 megatons of TNT
That is about 252 times the Hiroshima bomb. It released about 7,943 times the energy of a magnitude 5.0.
Tectonic setting
43 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
24 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 200 km
USGS lists 2 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M5.5 on March 31, 1965. 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 141 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.71965 Western Aleutian Islands (Hawadax/Rat Islands) EarthquakeFebruary 4, 1965 · 122 km NE of this epicenter
- 8.31906 Western Aleutian Islands (Hawadax/Rat Islands) EarthquakeAugust 17, 1906 · 176 km N of this epicenter
- 7.4265 km WSW of Adak, AlaskaFebruary 4, 1965 · 176 km NE of this epicenter
- 7.2238 km SSE of Attu Station, AlaskaSeptember 8, 1939 · 220 km W of this epicenter
- 7.2238 km WSW of Adak, AlaskaMarch 22, 1905 · 186 km NE of this epicenter
- 7.2162 km WSW of Adak, AlaskaMarch 16, 1957 · 261 km NE of this epicenter
- 7.0Rat Islands, Aleutian Islands, AlaskaFebruary 6, 1916 · 99 km NE of this epicenter
- 7.0148 km WSW of Adak, AlaskaMarch 11, 1957 · 274 km NE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 7 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1965M8.7
Aleutian Islands: Rat Islands
4 Feb 1965 · 122 km away · intensity VI
Under $1 million damagetsunami
- 1906M8.3
Aleutian Islands: Rat Islands
17 Aug 1906 · 176 km away
- 1905M7.9
Andreanof Islands
14 Feb 1905 · 257 km away
- 1909M7.8
Aleutian Islands
10 Apr 1909 · 277 km away
- 1916M7.7
Aleutian Islands
6 Feb 1916 · 204 km away
- 1965M7.6
Aleutian Islands: Rat Islands
30 Mar 1965 · 5 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.