• Official Name: Kasatochi Island
  • Seismically Monitored: No
  • Color Code: UNASSIGNED
  • Alert Level: UNASSIGNED
  • Elevation: 314m (1030ft)
  • Latitude: 52.1693
  • Longitude: -175.5113
  • Smithsonian VNum: 311130
  • Nearby Towns:
    • Adak 52 mi (83 km) SW
    • Atka 56 mi (89 km) NE
    • Nikolski 284 mi (457 km) NE
    • Saint George 389 mi (626 km) NE
    • Unalaska 391 mi (629 km) NE


From Miller and others (1998) [1] : "Kasatochi Island, like Gareloi, Bogoslof, and several other volcanoes in the western Aleutian arc, represents the emergent summit of a predominantly submarine volcano. The island consists of a single, undissected cone with a central lake-filled crater about 0.75 km in diameter. A maximum height of 314 m is on the southern crater rim; elevation of the lake is less than about 60 m. Kay (1990) [2] reports a lava dome on the northwest side of the cone at an elevation of ~150 m.
"Coats (1956) [3] referred to Kasatochi as one of a group of little-known volcanoes that appear to be stratovolcanoes composed of basaltic and andesitic flows and pyroclastics. The mean slope of the southern flank (about 18 degrees) is considerably less than the mean slope of the northern flank (about 45 degrees). This asymmetry of form may reflect a predominance of lava flows low on the southern flanks, or, it may be due to a higher rate of erosion by wave action from the north. Bathymetry indicated that Kasatochi is at the northern end of a 15-km-long, 6-km-wide submarine ridge that is normal to the trend of the Andreanof Islands. Water depths along the ridge are less than 90 m; if Kasatochi is constructed entirely on the ridge, the total height of the volcanic pile is only a little more than 400 m."

Name Origin

"Kasatochi Island" is a Russian name published as "Kosatochyey" by Lieutenant Sarichev (1802), shown as "L'ile Kassatotchy" by Lutke (1836), and as "O[strov] Kasatochiy" on the Russian Hydrographic Department Chart 1400 (1848) (Orth, 1971). Bergsland (1959) records the Unangam Tunuu place name of Kasatochi as "qana-tanar," meaning "which island," as in "which island is it that is emerging out there."

References Cited

[1] Catalog of the historically active volcanoes of Alaska, 1998

Miller, T. P., McGimsey, R. G., Richter, D. H., Riehle, J. R., Nye, C. J., Yount, M. E., and Dumoulin, J. A., 1998, Catalog of the historically active volcanoes of Alaska: U.S. Geological Survey Open-File Report 98-0582, 104 p.

[2] Volcanoes of North America: United States and Canada, 1990

Wood, C. A., and Kienle, Juergen, (eds.), 1990, Volcanoes of North America: United States and Canada: New York, Cambridge University Press, 354 p.

[3] Reconnaissance geology of some western Aleutian Islands, Alaska, 1956

Coats, R. R., 1956, Reconnaissance geology of some western Aleutian Islands, Alaska: in Investigations of Alaskan volcanoes, U.S. Geological Survey Bulletin 1028-E, p. 83-100, 1 sheet, scale unknown.
full-text PDF 4.4 MB
plate 17 PDF 1.6 MB

Current Activity

No new updates for Kasatochi volcano since October 31, 2008, 1:42 pm.

Color Code Timeline


Loading Past Activity...

Loading Images...

Loading Maps...

Loading Bibliography...