Reviewed by USGSAlaska97y ago
M6.5 earthquake 173 km ENE of Atka, Alaska
Saturday, December 6, 1930, 07:03:28 UTC · 53.000°N, 172.000°W
A magnitude 6.5 earthquake struck 173 km ENE of Atka, Alaska on Saturday, December 6, 1930, 07:03:28 UTC, at a depth of 80.0 km (intermediate). It is the strongest earthquake within 300 km since an M7.8 on March 7, 1929.
- Magnitude
- 6.5
- Strong · ms
- Depth
- 80 km
- Intermediate
- 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
85 kilotons of TNT
That is about 6 times the Hiroshima bomb. It released about 178 times the energy of a magnitude 5.0.
Tectonic setting
200 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: intermediate
80 km
Intermediate-depth earthquakes usually break inside a plate that is sinking into the mantle. Shaking spreads over a wide area but is gentler at the epicenter than a shallow quake of the same size.
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 20 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 · 278 km SE of this epicenter
- 7.4133 km WNW of Nikolski, AlaskaApril 18, 1916 · 101 km NE of this epicenter
- 6.9182 km SSE of Atka, AlaskaJanuary 27, 1906 · 249 km S of this epicenter
- 6.9100 km ESE of Adak, AlaskaOctober 13, 1926 · 278 km SW of this epicenter
- 6.6135 km SW of Nikolski, AlaskaDecember 23, 1906 · 171 km SE of this epicenter
- 6.596 km SSE of Nikolski, AlaskaSeptember 8, 1909 · 265 km E of this epicenter
- 6.556 km E of Adak, AlaskaJuly 17, 1914 · 287 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:
- 1901M7.8
Aleutian Islands: Fox Islands
31 Dec 1901 · 185 km away
Limited damage (under $1M)tsunami
- 1917M7.9
Alaska Peninsula
31 May 1917 · 274 km away · intensity V
- 1907M7.8
Aleutian Islands
2 Sep 1907 · 159 km away
- 1929M7.8
Aleutian Islands: Fox Islands
7 Mar 1929 · 261 km away · intensity V
tsunami
- 1916M7.5
Aleutian Islands: Fox Islands
18 Apr 1916 · 137 km away
- 1872
Aleutian Islands: Fox Islands
23 Aug 1872 · 253 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.