Reviewed by USGSAlaska61y ago
M6.8 earthquake 17 km N of Ouzinkie, Alaska
Saturday, September 4, 1965, 14:32:51 UTC · 58.079°N, 152.557°W
A magnitude 6.8 earthquake struck 17 km N of Ouzinkie, Alaska on Saturday, September 4, 1965, 14:32:51 UTC, at a depth of 28.6 km (shallow). It is the strongest earthquake within 300 km since an M7.1 on November 7, 1912.
- Magnitude
- 6.8
- Strong · mw
- Depth
- 29 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- VII
- Very strong (ShakeMap)
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeDashed circle: 100 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)
In context
How big was it, and why here?
Energy released
231 kilotons of TNT
That is about 15 times the Hiroshima bomb. It released about 484 times the energy of a magnitude 5.0.
Tectonic setting
210 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
29 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 M5.6 on September 8, 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 171 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.9Kodiak Island region, AlaskaOctober 9, 1900 · 119 km SE of this epicenter
- 7.14 km ENE of Karluk, AlaskaNovember 7, 1912 · 121 km SW of this epicenter
- 7.0153 km SE of Halibut Cove, AlaskaDecember 23, 1906 · 188 km E of this epicenter
- 6.8Event 48 Novarupta-Mount Katmai area, Alaska PeninsulaJune 10, 1912 · 156 km W of this epicenter
- 6.7120 km S of Akhiok, AlaskaApril 10, 1957 · 260 km S of this epicenter
- 6.688 km SSE of Old Harbor, AlaskaDecember 21, 1917 · 182 km S 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:
- 1900M8.3
Kodiak Island
9 Oct 1900 · 123 km away · intensity VIII
Limited damage (under $1M)
- 1788M8.0
Unga Island
21 Jul 1788 · 123 km away · intensity VII
Limited damage (under $1M)tsunami
- 1792
Kodiak Island
1792 · 124 km away · intensity VII
Limited damage (under $1M)tsunami
- 1906M7.6
Aleutian Islands
23 Dec 1906 · 159 km away
- 1912M7.5
Alaska Peninsula
7 Nov 1912 · 158 km away · intensity V
- 1854
Gulf Of Alaska
27 Jan 1854 · 124 km away · intensity V
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.