The volcano is located within the East Kamchatka volcanic belt. The volcano is 20 km from the Uzon caldera, 25 km from the Maly Semyachik volcano, 170 km from Petropavlovsk-Kamchatsky.

Bolshoy Semyachik Volcano is a complex volcanic structure with a caldera 10 km in diameter, in which eight cone-shaped stratovolcanoes with a base diameter of 3-4 to 8-9 km are located, overlapping its eastern side: Zubchatka, Baraniy, Problematichny, Plosky, Kulakova, Popkova, Burlyashchiy, Tsentralny Semyachik. The space between them is occupied by numerous domes and cinder cones with lava flows.

Explosive eruptions of stratovolcanoes with ash removal up to 6-8 km above sea level, as well as the formation of cinder cones and lava domes, and an effusinf of lava flows are possible.

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