Complex sentence: It is the most active volcano on the Kamchatka Peninsula, as well as the most active volcano of Kamchatka's eastern volcanic zone, a symmetrical stratovolcano constructed within a 5-km-wide caldera that formed during the early Holocene.
Split into simpler sentences: It is the most active volcano on the Kamchatka Peninsula, as well as the most active volcano of Kamchatka's eastern volcanic zone. Karymsky is a symmetrical stratovolcano rising within a 5-km-wide caldera that formed during the early Holocene.