Reviewed by USGSAlaska10y ago
M3.0 earthquake 185 km E of Atka, Alaska
Wednesday, December 30, 2015, 07:36:39 UTC · 52.547°N, 171.539°W
A magnitude 3.0 earthquake struck 185 km E of Atka, Alaska on Wednesday, December 30, 2015, 07:36:39 UTC, at a depth of 54.6 km (shallow).
- Magnitude
- 3.0
- Minor · ml
- Depth
- 55 km
- Shallow
- Felt reports
- 0
- Max intensity I
- 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
477 kg of TNT
That is about 1/31,575 of the Hiroshima bomb. A magnitude 5.0 releases about 1,000 times more energy.
Tectonic setting
143 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
55 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 3 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M3.0 on January 18, 2016. 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 845 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.01986 Atka, Alaska EarthquakeMay 7, 1986 · 249 km SW of this epicenter
- 7.8234 km SSW of Nikolski, AlaskaMarch 7, 1929 · 219 km SE of this epicenter
- 7.881 km E of Nikolski, AlaskaJuly 2, 1965 · 266 km E of this epicenter
- 7.4133 km WNW of Nikolski, AlaskaApril 18, 1916 · 115 km NE of this epicenter
- 7.3Fox Islands, Aleutian Islands, AlaskaJune 24, 2011 · 59 km S of this epicenter
- 7.158 km WNW of Atka, AlaskaFebruary 28, 1970 · 229 km W of this epicenter
- 7.135 km SW of Nikolski, AlaskaMarch 11, 1957 · 159 km E of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 15 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1986M8.0
Aleutian Islands: Adak
7 May 1986 · 249 km away · intensity VI
Moderate damage ($1–5M)tsunami
- 1901M7.8
Aleutian Islands: Fox Islands
31 Dec 1901 · 127 km away
Limited damage (under $1M)tsunami
- 1965M6.5
Aleutian Islands: Fox Islands
2 Jul 1965 · 274 km away
Limited damage (under $1M)tsunami
- 1917M7.9
Alaska Peninsula
31 May 1917 · 296 km away · intensity V
- 1902M7.8
Aleutian Islands: Fox Islands
1 Jan 1902 · 274 km away
- 1907M7.8
Aleutian Islands
2 Sep 1907 · 122 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.