Reviewed by USGSAlaska14y ago
M4.2 earthquake 120 km ENE of Atka, Alaska
Saturday, June 16, 2012, 15:06:32 UTC · 52.514°N, 172.506°W
A magnitude 4.2 earthquake struck 120 km ENE of Atka, Alaska on Saturday, June 16, 2012, 15:06:32 UTC, at a depth of 197.0 km (intermediate).
- Magnitude
- 4.2
- Light · mb
- Depth
- 197 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
30 tons of TNT
That is about 1/500 of the Hiroshima bomb. A magnitude 5.0 releases about 16 times more energy.
Tectonic setting
157 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
197 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 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 822 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 · 242 km SW of this epicenter
- 8.01986 Atka, Alaska EarthquakeMay 7, 1986 · 191 km SW of this epicenter
- 7.8234 km SSW of Nikolski, AlaskaMarch 7, 1929 · 259 km SE of this epicenter
- 7.65 km WNW of Adak, AlaskaFebruary 14, 1905 · 294 km W of this epicenter
- 7.4133 km WNW of Nikolski, AlaskaApril 18, 1916 · 161 km NE of this epicenter
- 7.3Fox Islands, Aleutian Islands, AlaskaJune 24, 2011 · 69 km SE of this epicenter
- 7.158 km WNW of Atka, AlaskaFebruary 28, 1970 · 163 km W 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, which together caused about 2 recorded deaths. The most severe:
- 1957M8.6
Alaska
9 Mar 1957 · 242 km away
2 deathsSevere damage ($5–24M)tsunami
- 1986M8.0
Aleutian Islands: Adak
7 May 1986 · 191 km away · intensity VI
Moderate damage ($1–5M)tsunami
- 1901M7.8
Aleutian Islands: Fox Islands
31 Dec 1901 · 156 km away
Limited damage (under $1M)tsunami
- 1907M7.8
Aleutian Islands
2 Sep 1907 · 188 km away
- 1929M7.8
Aleutian Islands: Fox Islands
7 Mar 1929 · 241 km away · intensity V
tsunami
- 1916M7.5
Aleutian Islands: Fox Islands
18 Apr 1916 · 189 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.