The basaltic Malaya Udina rises above a low saddle at the eastern end of the complex; small lava domes also occur on its flanks. This volcano is located within the Volcanoes of Kamchatka, a UNESCO World Heritage site.
The andesitic western volcano, Bolshaya Udina, has a prominent lava dome on its southwestern flank. Bolshaya Udina, long believed to be extinct, has shown signs of seismic unrest and was re-classified as 'active' in June 2019.