Abstract
Active tectonic structures recorded in late Quaternary basin-fill sediments and geomorphology were elucidated, with special reference to the type of Quaternary tectonic movements in the Shinjo basin, Northeast Japan. The eastern part of the Izumita lowland (a small alluvial basin) is bounded by the Shinjo-higashiyama reverse fault. It is a tilting basin because the basin sediments are tilted toward the Shinjo-higashiyama fault. Hilltop surfaces (ca. 300 ka), which are deformed locally by reverse faults, are distributed widely in the Shinjo Basin. This shows that the Shinjo Basin has uplifted regionally at least since the Middle Pleistocene. The separation of hilltop surfaces from the Izumita lowland was caused by simultaneous tectonic movements such as regional uplifting and displacement of the Shinjo-higashiyama fault.
