*Mayu Unno1, Sayuri Takaboshi1, Akari Kinase1, Satsuki Yamazaki1, Mako Sato1, Mizuki Sagi1, Syunsuke Sato1, Ren Moriizumi1, Tomoya Niwa1, Syoma Chiba1, Kohe Shiseki1
(1.Ibaraki Prefectural Hitachi First Senior High School)
Keywords:coastal erosion , Ose coast, ocean current
In recent years, in the Ibaraki Prefecture, north coast have been reported to beach erosion. For close Ose coast from school, was examined in the past of aerial photographs, topographic variation seen and beach erosion was observed. This study, and the actual condition of the terrain change in Ose coast, consider the relationship between ocean currents.We are, through March of this year from last July, and terrain surveying Ose coast of beach terrain (50m × 30m square) in about 50 days every, examined the changes in the terrain surface of the sandy coast. As a result, July to 12 months was seen erosion of beach terrain surface is reduced average 52cm. December to three months following the deposition of beach terrain surface is average 26cm rise was observed. Thus, it was the result of beach terrain surface than at the start of the survey is the average 26cm erosion as a whole. As factors that cause of these terrain variation, was discussed focused on the ocean current that flows through the study area coast.We will use the data of the Japan Meteorological Agency, were examined, such as the flow rate of the ocean current that flows through the study area coast. As a result, the center from 8 to October erosion trend continued fast flow rate of ocean currents, ocean currents were many days that flows through the south-facing. In addition, December to March the deposition trend was followed by the slow flow rate of ocean currents, an increase in the number of days that flows northward, also had increased the number of days the ocean current itself does not flow.From the above, Ose coast by ocean currents flow rate of the south-facing is fast (Oyashio origin) is eroded, deposited the flow rate of the north is by slow ocean currents (Kuroshio origin) is considered to have been made.