Reviewed by USGSAlaska22y ago
M3.4 earthquake in Rat Islands, Aleutian Islands, Alaska
Saturday, December 18, 2004, 17:07:21 UTC · 51.020°N, 178.906°E
A magnitude 3.4 earthquake struck in Rat Islands, Aleutian Islands, Alaska on Saturday, December 18, 2004, 17:07:21 UTC, at a depth of 42.3 km (shallow).
- Magnitude
- 3.4
- Minor · ml
- Depth
- 42 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 earthquakeDashed circle: 50 km aftershock search area
In context
How big was it, and why here?
Energy released
2 tons of TNT
That is about 1/7,931 of the Hiroshima bomb. A magnitude 5.0 releases about 251 times more energy.
Tectonic setting
48 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
42 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 50 km
USGS lists 1 M2.5+ earthquake within 50 km in the following 30 days; the largest was M3.9 on January 16, 2005. 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 737 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 · 29 km NW of this epicenter
- 8.31906 Western Aleutian Islands (Hawadax/Rat Islands) EarthquakeAugust 17, 1906 · 105 km NW of this epicenter
- 7.977 km WSW of Adak, AlaskaJune 10, 1996 · 248 km E of this epicenter
- 7.8Rat Islands, Aleutian Islands, AlaskaNovember 17, 2003 · 23 km NW of this epicenter
- 7.6Rat Islands, Aleutian Islands, AlaskaMarch 30, 1965 · 109 km SW of this epicenter
- 7.4265 km WSW of Adak, AlaskaFebruary 4, 1965 · 67 km NE of this epicenter
- 7.388 km WSW of Adak, AlaskaJuly 7, 1929 · 239 km E of this epicenter
- 7.346 km SSW of Adak, AlaskaJune 10, 1996 · 300 km E of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 12 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 · 29 km away · intensity VI
Under $1 million damagetsunami
- 1906M8.3
Aleutian Islands: Rat Islands
17 Aug 1906 · 105 km away
- 1905M7.9
Andreanof Islands
14 Feb 1905 · 181 km away
- 1996M7.9
Andreanof Islands
10 Jun 1996 · 248 km away · intensity VI
tsunami
- 1909M7.8
Aleutian Islands
10 Apr 1909 · 291 km away
- 2003M7.8
Aleutian Islands: Rat Islands
17 Nov 2003 · 23 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.