Tephrostratigraphy and Eruption History of Kozushima Volcano, Izu Islands, Central Japan during the Last 30,000 Years

Kozushima is a volcanic island, located in the northern part of Izu Islands, approximately 170 km SSW central Tokyo. The volcanism Volcano started at 80-60 ka and formed monogenetic volcanoes. latest eruption occurred AD 838, was associated with formation lava dome pyroclastic cone Tenjo-san. In order to contribute long-term forecasting eruptions on Islands off Tokyo, tephrostratigraphy history during last 30,000 years reconstructed. According geological surveys, widespread Kikai-Akahoya (K-Ah; 7.3 cal ka) Aira-Tanzawa (AT; 30.0 tephras from southern Kyushu, Niijima-Mukaiyama (Nj-My; 886), Niijima-Shikinejima (Nj-Sk; 8 Niijima-Miyatsukayama (Nj-Mt; 12.8 Niijima 20 NNE are recognized. Tephras that also erupted Kozushima-Tenjosan (Kz-Tj; 838), Kozushima-Ananoyama (Kz-An; 7-9 c), Kozushima-Chichibuyama-A? (Kz-CbA?; 14-12.8 ka), Kozushima-Chichibuyama-A (Kz-CbA; 30-22 Kozushima-Chichibuyama-B (Kz-CbB; ca. 30 ka). Kz-An by activity chains (Kobe-yama–Anano-yama–Hanatate) just before Tenjo-san eruption. Kz-CbA? distributed Kozushima. Source vent distribution have not yet been identified. volcano over as follows. At ka, Kz-CbB Kozushima, Nachi-san Takodo-yama formed. Kz-CbA chain occurred. After Kz-CbA?, followed volcano. addition, rate estimated be 0.06 km3/1000 y DRE.