Udina is divided into Bolshaya Udina and Malaya Udina which are both stratovolcanoes that are Holocene in age. Bolshaya Udina is a 6,566 ft. cone that is cut with deep gullies and ravines. Malaya Udina which has the same deep cuts on its slopes, has a cone that is black in color with a jagged and pointed summit that reaches an elevation of 6,562 ft. above the surrounding area. The Udinas are made of basalt, andesite and dacite. Both Udinas are part of the Kliuchevskoi Group which includes the volcanoes: Tolbachik, Bezymianny, Kaman and Kliuchevskoi. Neither Bolshaya Udina nor Malaya has ever erupted in Historic times.
Krijanovsky, N., "Volcanoes of Kamchatka," GSAB, v. 45, pp. 529-550, June 30, 1934.
Marhinin, E.K. and Stratula, D.S., "Relationship Between Chemical Composition of Volcanic Rocks and Depth of the Seismofocal Layer as Shown by the Kliuchevskaya Volcanic Group (Kamchatka) and the Kurile-Kamchatka Island Arc," Bulletin of Volcanology, Tome XXXVII-2, pp. 175-182, 1973.