Reviewed by USGSAlaska22y ago
M2.9 earthquake 102 km S of Adak, Alaska
Monday, October 18, 2004, 15:19:30 UTC · 50.963°N, 176.421°W
A magnitude 2.9 earthquake struck 102 km S of Adak, Alaska on Monday, October 18, 2004, 15:19:30 UTC, at a depth of 33.1 km (shallow).
- Magnitude
- 2.9
- Minor · ml
- Depth
- 33 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 earthquake
In context
How big was it, and why here?
Energy released
338 kg of TNT
That is about 1/44,601 of the Hiroshima bomb. A magnitude 5.0 releases about 1,413 times more energy.
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
33 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 has not published any M2.5+ earthquake within 50 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 904 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.61957 Atka, Alaska EarthquakeMarch 9, 1957 · 81 km NE of this epicenter
- 8.01986 Atka, Alaska EarthquakeMay 7, 1986 · 130 km NE of this epicenter
- 7.977 km WSW of Adak, AlaskaJune 10, 1996 · 108 km NW of this epicenter
- 7.65 km WNW of Adak, AlaskaFebruary 14, 1905 · 105 km N of this epicenter
- 7.4265 km WSW of Adak, AlaskaFebruary 4, 1965 · 283 km W of this epicenter
- 7.388 km WSW of Adak, AlaskaJuly 7, 1929 · 109 km NW of this epicenter
- 7.346 km SSW of Adak, AlaskaJune 10, 1996 · 64 km NW of this epicenter
- 7.2238 km WSW of Adak, AlaskaMarch 22, 1905 · 241 km W of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 8 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 · 81 km away
2 deathsSevere damage ($5–24M)tsunami
- 1986M8.0
Aleutian Islands: Adak
7 May 1986 · 130 km away · intensity VI
Moderate damage ($1–5M)tsunami
- 1905M7.9
Andreanof Islands
14 Feb 1905 · 152 km away
- 1996M7.9
Andreanof Islands
10 Jun 1996 · 108 km away · intensity VI
tsunami
- 1996M7.3
Andreanof Islands
10 Jun 1996 · 64 km away
tsunami
- 1971M7.1
Andreanof Islands
2 May 1971 · 73 km away · intensity VI
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.