Geoinformation analysis of variability state of the natural environment after eruption of the Chikurachki volcano by remote sensing data

Abstract

Explosive volcanic eruptions pose certain danger for natural environment, transport communications and other objects of human economic activity due to the fact that during such eruptions, up to several cubic kilometers of volcanic ash and aerosols can enter to atmosphere in long time. The research of extent of the impact of volcanic eruptions on surrounding area and the determination of their consequences contributes to reasonable assessment of volcanic hazard and possible risks in time conduct of economic activities and ensuring for safe location of settlements, enterprises, sea way and air lines. Chikurachki volcano is one from most active on territory of the Kuril Island Arc. In articles of volcanologists is information about eruptions in 1853–1859, 1958, 1961, 1964, 1973, 1986, 2002, 2003, 2005, 2007, 2008, 2015, 2016. The vegetation index (NDVI) used as means of assessing state of the natural environment. The boundary dividing areas with disturbed and healthy vegetation cover taken along isoline with NDVI value of 0.4. Schematic maps of the dynamics of boundary isolines according for the vegetation index from 1972 to 2020 has been compiled. The dynamics of vegetation cover in the north-eastern, south-eastern and southern sectors relative to Chikurachki volcano is revealed. The north-eastern sector experienced strong negative impact of eruption of the Chikurachki volcano in 1853, at later (2007 and 2015) only ash falls were observed in this direction. The vegetation cover outside the isoline NDVI = 0.4 has almost completely recovered to 2020. The south-eastern sector damaged during eruption of 1986, and was also subject for periodic tephra precipitation and ash falls during 2002–2016. Vegetation was completely destroyed at distance of 9 km from the crater of the volcano, and also valley forests on Tukharka River were destroyed. In southern sector in upper part of the Vernadsky Ridge, harsh growing conditions do not allow vegetation to recover for decades. At the same time, on eastern and western slopes of the ridge, after eruptions with deposition of tephra by layer of small thickness, alder elfin restoration few years. The results of the recearch can be used in forecasting volcanic hazards and rapid assessment of impact on natural environment of territories adjacent to volcanoes of this type as a result of volcanic eruptions.