The paleo-Tokyo, Naka, Ara, and Tama river valleys were formed beneath the central area of the Kanto Plain during the Last Glacial Maximum (LGM). These incised valleys run parallel to the northwest-southeast trending geological structure of the Median Tectonic Line. Branches of these incised valleys dissect the upper Pleistocene uplands that surround the coastal lowlands. At least four buried terraces were identified in the study area, referred to as Omiya marine isotope stage (MIS) 5c, T1 (MIS

more »

... 5a), T2 (MIS 3), and T3 (early LGM) surfaces. The Omiya surface rises toward the west in the northern part of the study area beneath the Kazo Lowland, possibly as a result of uplift along the Ota fault.