The geological and geophysical research carried out during the five cruises of R/V/ Vulkanolog in the 1980s and early 1990s provided new evidence of the structure and evolution of the Chernye Bratya volcanic massif. Five phases have been identified in its evolution. The first phase which began in the Early - Middle Pleistocene, or possibly Neogene, involvel the generation of a major shield-shaped, mostly laval, volcanic massif with dimensions 30 km by 35 km. The secondphase seems to have been a catastrophic explosive eruption producing the older caldera (Gorshkov Outer Caldera) of dimensions 15 km by 20 km. It is not younger than the mid-Late Pleistocene. A large volcanic structure formed during the third phase in the north and central parts of the older caldera, filling most of the caldera and overlapping its rim. A major explosive eruption occurred during the fourth phase producing the younger caldera (Gorshkov Caldera) of dimensions 7.5 km by 11.5 km. The generations time of that caldera corresponds to a powerful burst of acid explosive volcanism in the Kuril-Kamchatka region about 45.000 to 30.000 years ago. The final phase involved high volcanic activity within the younger caldera producing the present-day volcanic edifices of Chirpoy and Brat Chirpoev islands near the caldera rim. The total volume of ejecta discharged in the area may be in excess of 1000-1300 km 3; of these, 400-600 km 3 consist of pyroclastic material produced by the caldera-generating eruptions.

During the voyages of R\V Vulkanolog in the eighties of the last century the kamchatkan scientists studied 17 geophysical profiles (about 1100 route kilometres) within the submarine Shokalsky Ridge. The investigation showed that the Shokalsky Ridge is comprised of 4 large volcanic massives. Numerous faults were revealed within the ridge area, including those with traces of recent activity. Shift amplitude along some faults may be as long as several hundreds of meters. Canyons that split the Shokalsky Ridge are chiefly confined to the cross keystone faults.

There has been given a new data regarding morphology of submarine volcanic ridges Gidrographov and Browton (Kurile island arc). Within the limits of this ridges there has been discovered four new submarine volcanoes, that has not been included in the Catalogue of «Submarine volcanoes and mountains of Kurile island arc». Two in the Gidrographov ridge and two in the Browton ridge.