Koshelev, also known as Chaokhch, is a compound stratovolcano with a very large caldera that was formed in Pre-glacial time. The cone continued to erupt into the Post-glacial era. On the badly eroded western slope are very active solfataras, on the eastern side are cinder cones with basaltic flows, and to the west is the Sea of Okhotsk. At Koshelev's summit there are two craters. The eastern crater is fresh and active, the northwestern has apparently not erupted for a long time and is becoming an erosion caldera. Scientists believe that at the end of the 17th century Koshelev erupted with large explosive eruptions. Some other volcanoes in this area are: Kambalny, Pauzhetka, Ilyinsky, and Zhelotovsky.
Sources of Information:
Sviatolovsky, A. E. 1959 Atlas of Volcanoes of the Soviet Union, USSR Academy of Sciences, Moscow USSR. p168.
Vlodavetz V.I., Piip B. I. 1959 Kamchatka and Continental Areas of Asia. Catalog of Active Volcanoes of the World, Rome IAVCEI, 8: p3-4.
Gushchenko, I.I. 1979 Izverzheniya Vulkanov Mira: Katalog (In Russian), Hauka, Moscow p.27.