Reviewed by USGSAlaska18y ago
M3.2 earthquake 130 km WNW of Adak, Alaska
Thursday, July 31, 2008, 02:09:20 UTC · 52.172°N, 178.470°W
A magnitude 3.2 earthquake struck 130 km WNW of Adak, Alaska on Thursday, July 31, 2008, 02:09:20 UTC, at a depth of 203.9 km (intermediate).
- Magnitude
- 3.2
- Minor · m
- Depth
- 204 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 earthquakeDashed circle: 50 km aftershock search area
In context
How big was it, and why here?
Energy released
951 kg of TNT
That is about 1/15,825 of the Hiroshima bomb. A magnitude 5.0 releases about 501 times more energy.
Tectonic setting
186 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
204 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 50 km
USGS lists 3 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M4.7 on August 19, 2008. 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 1,017 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 · 219 km SW of this epicenter
- 8.61957 Atka, Alaska EarthquakeMarch 9, 1957 · 209 km E of this epicenter
- 8.31906 Western Aleutian Islands (Hawadax/Rat Islands) EarthquakeAugust 17, 1906 · 232 km W of this epicenter
- 8.01986 Atka, Alaska EarthquakeMay 7, 1986 · 264 km E of this epicenter
- 7.977 km WSW of Adak, AlaskaJune 10, 1996 · 89 km SE of this epicenter
- 7.8Rat Islands, Aleutian Islands, AlaskaNovember 17, 2003 · 229 km SW of this epicenter
- 7.65 km WNW of Adak, AlaskaFebruary 14, 1905 · 125 km E of this epicenter
- 7.4265 km WSW of Adak, AlaskaFebruary 4, 1965 · 156 km SW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 14 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 · 209 km away
2 deathsSevere damage ($5–24M)tsunami
- 1986M8.0
Aleutian Islands: Adak
7 May 1986 · 264 km away · intensity VI
Moderate damage ($1–5M)tsunami
- 1965M8.7
Aleutian Islands: Rat Islands
4 Feb 1965 · 219 km away · intensity VI
Under $1 million damagetsunami
- 1906M8.3
Aleutian Islands: Rat Islands
17 Aug 1906 · 232 km away
- 1905M7.9
Andreanof Islands
14 Feb 1905 · 160 km away
- 1996M7.9
Andreanof Islands
10 Jun 1996 · 89 km away · intensity VI
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.