Environmental change and human activity around Megazuka in the Ukishimagahara Lowland, Shizuoka Prefecture

The Ukishimagahara Lowland is situated along the innermost margin of Suruga Bay. A barrier-backswamp system is recognized along the present coastline. Three coastal barriers are called barriers I to III, in order from landward to seaward. Megazuka is an archaeological site located in the middle of the Ukishimagahara Lowland. Excavated materials indicate that Megazuka was occupied by pre-historical people from the middle of the Jomon period (ca 4000 yr BP) until the middle of the Kofun period (ca 1500 yr BP). The purpose of this paper is to discuss the influence of environmental changes on human activity in the Ukishimagahara Lowland. The development of coastal barriers in the Ukishimagahara Lowland and the environmental changes around Megazuka are summarised. The relationships between environmental changes and human activity at Megazuka are inferred. The initial stage of human activity coincided with the period when the area around Megazuka changed from a lagoon to a backswamp with the construction of the coastal barrier II (ca 4000 yr BP). The initial stage of human settlement was coincident with the period when coastal barrier III was completed and came to enclose the backswamp (ca 2000 yr BP). The human settlement at Megazuka was abandoned at the time of the fall of the Obuchi Scoria (ObS) from Mt. Fuji (ca 1500 yr BP). Tectonic movement in the Ukishimagahara Lowland is characterised by subsidence, which buried the former coastal barriers beneath the backswamp. -from English summary