Reviewed by USGSAlaska119y ago
M7.0 earthquake 167 km WSW of Attu Station, Alaska
Saturday, April 10, 1909, 19:34:51 UTC · 52.244°N, 170.919°E
A magnitude 7.0 earthquake struck 167 km WSW of Attu Station, Alaska on Saturday, April 10, 1909, 19:34:51 UTC, at a depth of 35.0 km (shallow). It is the strongest earthquake within 300 km since an M7.4 on September 2, 1907.
- Magnitude
- 7.0
- Major · 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
494 kilotons of TNT
That is about 33 times the Hiroshima bomb. It released about 1,035 times the energy of a magnitude 5.0.
Tectonic setting
15 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 200 km
USGS has not published any M2.5+ earthquake within 200 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 3 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
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:
- 1909M7.8
Aleutian Islands
10 Apr 1909 · 280 km away
- 1898M7.6
Aleutian Islands: Near Islands
29 Jun 1898 · 79 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.