Abstract <p>The paper presents information on the deep structure of dynamically active regions of Central and Eastern Kamchatka in the island arc junction. It also discusses the inferred genetic relation of the ultramafic rocks and copper-nickel mineralization to the structural features of lithosphere in the continent–ocean transition zone. The paper reports the results of integrated interpretation of geophysical data derived by earthquake converted-wave method (ECWM), magnetotelluric sounding (MTS), gravity and magnetic surveys, as well as geological surveys carried out in the area of the Klyuchevskoy Group of volcanoes and Kamchatsky Mys Peninsula. For the first time, a geological and geophysical model has been developed for the Krapivnoe village–Cape Africa geophysical profile. The model shows the main boundaries of the lithosphere and identifies previously unknown elements of the Earth’s crust and upper mantle. In the western part of the model, an NE-dipping upper mantle layer is identified, the present-day movement of which can be explained by the involvement of the lower layer of the Eastern Kamchatka lithosphere in subduction of the oceanic plate beneath the Aleutian–Commander Arc. The dynamics of interaction between the oceanic and continental lithospheric plates is shown. Two subduction zones that have existed successively in the past are demonstrated schematically. The upper part of the second subducting slab contains a 12–16 km thick layer consisting of ophiolite sheets and blocks of ultramafic and mafic composition. One of the identified blocks in the layer is presumably a part of an ultramafic massif with copper-nickel mineralization. An extension zone located downsection is confined to the area of maximum slab bending. Natural thermal vents in the Cape Africa areas suggest the circulation of high-temperature solutions in the extension zone. The upper part of the model includes a block identified as a fragment of the Achaivayam–Valaginsky terrane. The block is represented by discrete sheet-like fragments of varying density, which are inclined in the eastern direction and consist of two layers 6 km of total thickness. The upper layer is made up of an allochthonous sheet, the frontal part of which consists of Paleocene–Eocene deposits thrust over the western slope of the Tyushevsky trough filled with Oligocene–Miocene deposits. The thrust was caused by the Central Kamchatka rift extension. The Tyushevsky trough was inherited from the accretion zone. Two areas where the trough base demonstrates submergence to a depth of 6 and 7 km are inherited from the deep-sea paleo-trenches formed during successive subductions.</p>