Mapping of dangerous geomorphic processes in the coastal zone of the islands of Peter the Great Bay (Primorskii Krai) on the complex morphogenetic base
The coastal zone of the islands of the south part of Primorsky Krai, due to its morphology, is the area of high exodynamic hazard. The rockfalls of coastal cliffs is the most dangerous process. Recent rockfall sediments are found everywhere. The second dangerous process is the one-time extreme transport of proluvium-mudflow material to beaches as a result of extensive (for example, typhoon) rains. It is noted that in order to minimize the negative consequences of dangerous geomorphological processes for the population, it is reasonable to use complex geomorphological mapping of coastal zone and monitoring of individual areas with a high probability of rockfalls and other hazards. Large-scale geomorphological mapping reveals morphogenetic types of coasts and landforms that are exposed to hazardous exogenous geomorphic processes or form them. The cartographic legend consists of four parts. A morphogenetic part is based on the legend of P.A. Kaplin et al. Three parts and consequently three cartographic layers reflect the additional aspects of landforms including morphogenetic structure of inner areas of the islands. It makes sense to compile the maps of the sections of the coastal zone with the visual signs of activation of these processes. It is also noted that identification of dangerous segments of coasts needs remote and field monitoring of the coastal areas of these rockfall sites and some streams of 1-2 Horton’s orders with a two years periodicity. The main objects of monitoring include the near-edge areas of steep coastal ledges, where rockfalls and landslides are formed, the ledges themselves and their correlated beaches as well as the near-mouth sections of the valleys of streams that “cut” coastal ledges. The working map should be in the form of an electronic document with updated data based on the monitoring results.