Reviewed by USGSAlaska22y ago
M3.3 earthquake 179 km W of Adak, Alaska
Saturday, March 27, 2004, 06:20:32 UTC · 51.651°N, 179.216°W
A magnitude 3.3 earthquake struck 179 km W of Adak, Alaska on Saturday, March 27, 2004, 06:20:32 UTC, at a depth of 44.5 km (shallow).
- Magnitude
- 3.3
- Minor · ml
- Depth
- 45 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
1 tons of TNT
That is about 1/11,203 of the Hiroshima bomb. A magnitude 5.0 releases about 355 times more energy.
Tectonic setting
127 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
45 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 2 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M3.4 on April 22, 2004. 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 858 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 · 150 km W of this epicenter
- 8.61957 Atka, Alaska EarthquakeMarch 9, 1957 · 249 km E of this epicenter
- 8.31906 Western Aleutian Islands (Hawadax/Rat Islands) EarthquakeAugust 17, 1906 · 181 km W of this epicenter
- 7.977 km WSW of Adak, AlaskaJune 10, 1996 · 110 km E of this epicenter
- 7.8Rat Islands, Aleutian Islands, AlaskaNovember 17, 2003 · 158 km W of this epicenter
- 7.6Rat Islands, Aleutian Islands, AlaskaMarch 30, 1965 · 254 km SW of this epicenter
- 7.65 km WNW of Adak, AlaskaFebruary 14, 1905 · 175 km E of this epicenter
- 7.4265 km WSW of Adak, AlaskaFebruary 4, 1965 · 86 km W of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 11 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 2 recorded deaths. The most severe:
- 1957M8.6
Alaska
9 Mar 1957 · 249 km away
2 deathsSevere damage ($5–24M)tsunami
- 1965M8.7
Aleutian Islands: Rat Islands
4 Feb 1965 · 150 km away · intensity VI
Under $1 million damagetsunami
- 1906M8.3
Aleutian Islands: Rat Islands
17 Aug 1906 · 181 km away
- 1905M7.9
Andreanof Islands
14 Feb 1905 · 112 km away
- 1996M7.9
Andreanof Islands
10 Jun 1996 · 110 km away · intensity VI
tsunami
- 2003M7.8
Aleutian Islands: Rat Islands
17 Nov 2003 · 158 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.