Stardust Bay, Sedanka Island

Stardust Bay, Sedanka Island

by | Apr 29, 2024

Stardust Bay is situated on the southeast coast of Sedanka Island, which is separated from Unalaska Island by Udagak Strait to the west and Beaver Inlet to the north, about 780 miles (1258 km) southwest of Anchorage and 16 miles (26 km) southeast of Dutch Harbor, Alaska. The bay is named after a fishing vessel that wrecked on the steep, high-energy, east-facing beach at the head of the bay. Sedanka Island is one of the Fox Islands in the Eastern Aleutian Islands, and is about 11 miles (18 km) long and 5 miles (8 km) wide and deeply incised by fjords.  In 1792, Lieutenant Gavril Sarichev of the Imperial Russian Navy named the island ‘Spirkin’, but that same year Martin Sauer gave the Aleut name ‘Sithanak’ which Marcus Baker recorded as ‘Siginak’ meaning ‘braided’ or ‘curled’. The U.S. Coast and Geodetic Survey named the island ‘Sedanka’ on charts from 1921. The island is mostly formed by slightly altered andesite and basalt dikes, and sedimentary rocks consisting of argillite and conglomerate. The southwestern part of the island is a grandiorite batholith.

Sedanka Island is uninhabited, but an Unangan Aleut village called Biorka was on the north coast until 1942 when it was evacuated during World War II and later abandoned. After the Russian-American Company depleted the sea otter population in the Aleutians, the village of Biorka shared the systemic poverty of the region. The residents turned to a variety of occupations such as trapping red and cross fox, and commercial fishing from Unalaska and the Pribilof Islands. In 1912 the U.S. Navy Alaskan Radio Expedition established a station on Unalga Island, about 10 miles (16 km) north of Sedanka Island, as part of a four-year effort to provide better communications linking coastal Alaska with Seattle. In 1915, The U.S. Revenue Cutter Manning reported Biorka consisting of ten barabaras for 17 adults and 13 children. Wood frame buildings first appeared in Biorka shortly after the closure of the radio station, probably from salvaged materials. On June 3, 1942, Dutch Harbor was bombed by Japanese aircraft and by the end of the month the Unangan Aleuts were evacuated from all the major villages in the Aleutian Islands by the SS Columbia, of the Alaska Steamship Company, to encampments established in Southeast Alaska.

Stardust Bay is funnel-shaped and exposed to the full force of waves generated in the Gulf of Alaska. This bay is the site of an ongoing study by the U.S. Geological Survey of very large tsunamis. Core samples and shallow pits have revealed a series of sand deposits from historical tsunamis that reached 0.5 miles (800 m) inland. Drift logs ringing the lowland floodplain approximate the landward limit of the most recent tsunami. The highest log found (a 10 m long by 0.25 m diameter pole) was nearly 0.6 miles (1 km) inland, bridging a narrow gully at an elevation of 60 feet (18.5 m). The drift logs came from Stardust Bay’s shoreline because driftwood litters the beach and, like other Aleutian Islands, no trees grow on Sedanka Island. Evidence suggests that intervals between historical tsunamis were as short as 170 years and as long as 570 years. On average, tsunamis of the past 1700 years inundated Stardust Bay every 300–340 years. Read more here and here. Explore more of Stardust Bay and Sedanka Island here:

About the background graphic

This ‘warming stripe’ graphic is a visual representation of the change in global temperature from 1850 (top) to 2022 (bottom). Each stripe represents the average global temperature for one year. The average temperature from 1971-2000 is set as the boundary between blue and red. The color scale goes from -0.7°C to +0.7°C. The data are from the UK Met Office HadCRUT4.6 dataset. 

Credit: Professor Ed Hawkins (University of Reading). Click here for more information about the #warmingstripes.

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