2002 年 6 巻 2 号 p. 19-28
Volcanic centres in and around Japan can be explained by the theory of plate tectonics. Large quantities of lava and tephra, mainly of rhyolitic and andesitic composition, have erupted throughout the Quaternary in thoses areas. Tephra layers, including not only fallout deposits but also flow deposits play an important role in characterising soils and landscapes as well as stratigraphic studies. A catalogue of tephras occurring there provides fundamental criteria for the establishment of a regional Quaternary chronostratigraphy. The basic tephra framework is reconstructed through recognition of widespread marker tephras. A detailed and regional chronology based on distal tephras has been improved with the aid of local, proximal tephras. The juxtaposition of dated marine and terrestrial tephras with paleoceanographic, terrestrial, sea-level and tectono-geomorphic (e.g., terrace) records has enabled a synthesis of event-associations that has improved significantly the under-standing of Quaternary events.
