February 4, 1965 Earthquake: Rat Islands, Aleutian Islands, Alaska, United States

Reference #414:

1965, Feb 3, 19:01 [local time]. There was a strong (6 degrees) earthquake on the Rat Islands and the Andreanof Islands. On Adak Island, a booming underground rumbling was heard; the oscillations began gradually and were regular; many residents were frightened; hanging objects fell from the walls; slight cracks were formed in some prefabricated wooden homes. On Attu Island, the oscillations began suddenly and consisted of both regular oscillations, as well as short-period trembling; lockers and wall pictures shifted; hairline cracks appeared in the landing strips at the naval base of the frontier guard. On Shemya Island, all unfastened objects rocked or fell; drawers came out of desks and cupboards; cracks appeared in the asphalt pavement; the stucco cracked. A seaquake was felt on the "Ohio" at 50 deg 48 min N., 179 deg 15 min E. Many aftershocks were registered. A tsunami arose.

Hwang et al., surmising that there was an instantaneous ellipsoid elevation of the bottom at the source of the earthquake, calculated the spread of the resulting tsunami over the Pacific Ocean. A distinct maximum of radiation turned out to follow a line orthogonal to the Aleutian arc, passing between Japan and the Hawaiian Islands.

Reference #542:

1965, Feb 4, 05:01:21.6 UTC. 51.29 N, 178.55 E, depth 36 km, magnitude 6.0 mb, 8.2 MS. 8.68 moment, intensity VI. Rat Islands, Aleutian Islands, Alaska. On Adak Island, cracks occurred in prefabricated wood buildings; on Shemya Island, cracks were observed in an asphalt runway. Hairline cracks also formed in the runways at the U.S. Coast Guard Loran Station on Attu Island. This earthquake generated a tsunami reported to be about 10.7 m high on Shemya Island. Loss caused by flooding on Amchitka Island was estimated at about $10,000. An aftershock at 07:40 UTC was assigned MMI VI. Magnitude 7.7 mb ABE, 7.7 Ukn PAS, 7.7 Ukn BRK (first shock); 7.0 mb ABE, 6.9 Ukn PAS (second shock).

Reference #1314:

1965, Feb 4. Magnitude 7.75 MS, 8.7 Mw.

Reference #13456 (access date 2023):

1965, Feb 4, 05:01:22 UTC. 51.251 N, 178.715 E, depth 30.3 km, magnitude 8.7 Mw

Reference #10476, v.10:

1965, Feb 4, 05:01:22.74 UTC. 51.251 N, 178.715 E, depth 30.3 km, magnitude 8.7 Mw