Reviewed by USGSAlaska116y ago
M6.8 earthquake 111 km SW of Adak, Alaska
Thursday, January 4, 1912, 15:46:57 UTC · 51.273°N, 177.928°W
A magnitude 6.8 earthquake struck 111 km SW of Adak, Alaska on Thursday, January 4, 1912, 15:46:57 UTC, at a depth of 35.0 km (shallow). It is the strongest earthquake within 300 km since an M6.9 on September 17, 1911.
- Magnitude
- 6.8
- Strong · mw
- Depth
- 35 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
215 kilotons of TNT
That is about 14 times the Hiroshima bomb. It released about 452 times the energy of a magnitude 5.0.
Tectonic setting
87 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
35 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 100 km
USGS has not published any M2.5+ earthquake within 100 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 8 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.31906 Western Aleutian Islands (Hawadax/Rat Islands) EarthquakeAugust 17, 1906 · 277 km W of this epicenter
- 7.65 km WNW of Adak, AlaskaFebruary 14, 1905 · 109 km NE of this epicenter
- 7.2238 km WSW of Adak, AlaskaMarch 22, 1905 · 135 km W of this epicenter
- 7.0101 km S of Adak, AlaskaSeptember 9, 1910 · 115 km E of this epicenter
- 6.9216 km SSE of Adak, AlaskaSeptember 17, 1911 · 226 km SE of this epicenter
- 6.7254 km SW of Adak, AlaskaSeptember 14, 1905 · 142 km SW of this epicenter
- 6.776 km SSE of Adak, AlaskaDecember 10, 1905 · 121 km E of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 2 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1906M8.3
Aleutian Islands: Rat Islands
17 Aug 1906 · 277 km away
- 1905M7.9
Andreanof Islands
14 Feb 1905 · 74 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.