Deposits of Tsunami 1983 and 1993 Years in the Primorye Coast
On the Eastern coast of Primorye deposits of two strongest tsunamis of the XX century were found, which had their epicenters in the Sea of Japan to the west from Hokkaido coast. The distribution and preservation of sediments in the bays of different geomorphological structure were analyzed. The most well sedimentary shits are expressed in the upper part of the sections of coastal lowlands in the bays, where the magnitude of the waves were more than 3 m, the best preservation of sediments observed in the bays dedicated to little streams. The structural composition changes of tsunamigenic deposits with distance from the shoreline were analyzed identified the sources of material. Tsunami waves were transferred sand not only from the beaches, ancient storm ridges and terraces, but also from the underwater coastal slope, and took material from estuarine lagoons and coastal lakes that were in the flood zone. Deposits include marine diatoms, which are dominated by sublittoral benthic and planktonic species, which suggests that the material came from a depth lesser than 15 meters. There are meet deep-sea species of diatoms and their fragments. Among the freshwater diatoms there are species with different ecological identity, indicating erosion and redeposition of material from various sources.