The great Mw8.7 Rat Islands underthrusting earthquake of February 4, 1965, ruptured a 600-km segment of the western end of the Aleutian Islands. The Rat Islands event was closely followed by a large tensional outer-rise event of March 30, 1965 (Ms 7.5, smaller star), which was located oceanward of the largest moment release associated with the Rat Islands mainshock rupture. This event may have been triggerred by the large displacement near the mainshock epicenter.

Last Modified: April 24, 2024