- Earthquakes
- Tsunamis
- Seismic Network
- About Us
Magnitude 8.7 - 26 miles SW of Amchitka
February 3, 1965 19:01:22 AST (February 4, 1965 05:01:22 UTC)
51.2900°N 178.5500°E Depth 22.4 miles (36 km)
This event has been reviewed by a seismologist
- 47 miles (76 km) S of Davidof Island
- 47 miles (76 km) S of Little Sitkin Pass
- 53 miles (85 km) S of Segula Peak
- 64 miles (103 km) SW of Semisopochnoi Island
- 70 miles (113 km) SE of Kiska Volcano
- 119 miles (192 km) W of Mt. Gareloi
- 134 miles (217 km) SE of Buldir Is
- 134 miles (217 km) SE of Buldir Island
- 148 miles (239 km) W of Tanaga Volcano
- 177 miles (286 km) W of Bobrof Island
- 189 miles (306 km) W of Kanaga Volcano
- Magnitude type: Mw2
- Event type: earthquake
To view any current tsunami advisories for this and other events please visit www.tsunami.gov
Tectonic Setting of the Aleutian Islands
The world's largest earthquakes originate along convergent plate boundaries such as the Aleutian megathrust. Starting in 1938, a series of three great earthquakes ruptured the subduction zone along its entire length from the Alaska Peninsula to the western Aleutians with the exception of a small gap near the Shumagin Islands. The sequence began with a M8.2 earthquake southwest of Kodiak Island. A M8.6 in the Andreanof Islands followed in 1957, and the sequence concluded with the Rat Islands M8.7 in 1965. The Shumagin Gap still has not ruptured, but GPS observations suggest that little strain has built up in this region.
Another notable source of seismicity in the arc are the intermediate depth earthquakes within the subducting Pacific Plate, known as the Wadati-Benioff zone. The largest recorded earthquake of this kind was the 2014 M7.9 Little Sitkin event. Shallow earthquakes associated with volcano processes and crustal faults within the overriding North American plate occur regularly and may produce vigorous aftershock or swarm-like sequences.