@article{oai:niigata-u.repo.nii.ac.jp:00027982, author = {ト部, 厚志 and 高濱, 信行}, journal = {新潟大学積雪地域災害研究センター研究年報, 新潟大学積雪地域災害研究センター研究年報}, month = {Dec}, note = {The Echigo Plain lies on the back-arc side of Honshu Island, facing the Sea of Japan. The thickness of the alluvium beneath the Echigo Plain reaches a maximum of 140m. The alluvium of the Echigo Plain is very thick compared to other alluvial plains in Japan probably because the Niigata area is located in an active tectonic zone in the back-arc side of the Japanese Islands and thus the Plain has continually subsided throughout the Holocene. The alluvium in the Niigata area shows high subsidence rates and provides a detailed record of glacio-eustatic changes of sea level in the Holocene, relative sea level changes due to tectonic movements, and changes in depositional system. Especially, the alluvium after Holocene maximum transgression provides important indications of the impact of tectonic movements on subsidence. On each core sample of the Ajikata, Yoroigata, Matsushima, Yamanoshita and Shimoyama in the Echigo Plain, this study examined the index volcanic ash and depositional facies. As this result, the transition of the sedimentary environment of each core was clarified, and the presence of the volcanic ash about 5000 BP of the Numazawa volcano origin also became clear. By the depositional facies analysis in these core and setting of the time base, it indicates that the plain is subsided at 13~19m during about 5000 year. This is the clear evidence that shows the subsiding of the alluvium.}, pages = {63--76}, title = {越後平野における沖積層の沈降と約5,000年前の指標火山灰}, volume = {24}, year = {2002} }