S.Yu. Grishin, S.A. Shlyakhov

Institute of Biology and Soil Science FEB RAS, Vladivostok

On the basis of the original materials obtained since 1978, the authors examine soil and vegetational cover within the zone of the strongest basalt eruption in Kamchatka. An intense ashfall in the summertime of 1975 caused the fall of enormous quantity of volcanites (0.7 km3). The ashfall destroyed vegetational cover over 100 km2 and damaged it over even larger territory. We consider the vegetational cover that existed prior to the eruption, the impact of the ashfall on the forest and alpine vegetation, and unclosed vegetation of the old lava flows. We calculated the area of the damaged vegetational cover and revealed the damage factors. The authors compared the damage factor of the vegetational cover caused by other ashfalls of the last century in Kurile-Kamchatkan region. Regional soils were studied for the first time.

Keywords: vegetation, soils, eruptions, ashfall, lava, succession, Tolbachik.