February 4, 1965 Tsunami: Rat Islands, Aleutian Islands, AK, United States

Reference #239:

1965, Feb 4, 0501 GMT. A magnitude 8.2 earthquake in the Rat Islands, Aleutian Islands, caused a tsunami that was observed in Hawaii, Japan, and elsewhere in the Pacific. The

earthquake caused minor damage at Adak, Attu, Amchitka, and Shemya Islands. At Sweeper Cove, Adak, the sea level fell 1.2 feet in fifteen minutes. At Massacre Bay, Attu, the water rose 5.2 feet relative to its normal position at that

time. It was recorded with an amplitude of 0.8 feet at Dutch Harbor, Unalaska, and 3 inches at Sitka.

On the southern coast of Shemya Island the rise of water was estimated at 35 feet. A warehouse was flooded and part of the coastal road was washed out. Slight damage from the tsunami was reported from Amchitka. A field party noted a

line of flotsam that appeared to have been moved about 6.5 feet above the normal high tide line.

The aftershock pattern outlined a block 400 miles by 125 miles (Jordan et al., 1965). Hwang et al. (1972) showed that the maximum energy followed the orthogonal to this block and passed between Hawaii and Japan. Validity 4.

Reference #542:

1965, Feb 4, 05:01 and 08:40 UTC. Rat Islands, Aleutian islands, Alaska. On Adak Island, cracks occurred in prefabricated wood buildings; on Shemway 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.

Reference #414:

1965, Feb 3, 19:01 [local time]. There was a strong (6 degrees) earthquake on the Rat Islands and the Andreanof Islands... A tsunami arose. On Adak Island, the sea level fell 0.3 m (1 foot) in 15 minutes. On Attu Island, the level rose and fell 2 1/2 m (8 feet) relative to the normal position. On the southern coast of Shemya Island, the height of rise of the water was estimated at 9-10 m (30-35 feet). Here the warehouse was flooded and a part of the coastal road was washed out. Slight damage from the tsunami was reported from Amchitka Island. In Japan on the Sanriku coast, slight damage was done to the oyster beds, although the rise of water was only a few tens of a centimetre. The tsunami was registered by many tide gauges in the Pacific. On the coasts of the USSR and Japan, the tsunami began with a tidal wave, the mean period of which was 25.5 minutes, The maximal amplitude of oscillations was observed in Japan 4-6 hours after the arrival of the first wave, regardless of the epicentral distance of the station.