INFLUENCE OF PYROCLASTIC EMISSION ON VALLEY MORPHOLOGY AND RIVER NETWORK DEVELOPMENT: THE CASE STUDY OF THE NORTHERN GROUP VOLCANOES, KAMCHATKA
On the sides of volcanoes the chain of paragenetic processes performs from the top and to the foot that includes volcanic, slope mass movement and erosion processes. River valleys provide transportation routes (“transport corridors”) for sediments involved in the lithodynamic system. Valleys are used by pyroclastic flows that transfer much volumes of sediments. Fluvial processes transport them from the upper parts to the foots of volcanoes. Physical properties of volcanic materials predetermine specific features of its reworking by water flows and thus exert influence on fluvial processes in river valleys. In the bottoms of river valleys, not alluvial but debris flow, mass movement, aeolian, thermokarstic processes dominate throughout the most part of year. Development of glaciation contributes to the increase of non-uniformity (“salvo” character) of lithodynamic flows and increase the area of pyroclastic material reworking by fluvial processes.