@article{oai:nagoya.repo.nii.ac.jp:00011473,
 author = {Okuno, Mitsuru},
 journal = {名古屋大学加速器質量分析計業績報告書},
 month = {Mar},
 note = {An advanced and sophisticated technique of radiocarbon (^<14>C) dating by accelerator mass spectrometry (AMS) has revealed a detailed eruptive history of the Aira caldera during the last 30,000 years. This caldera is located in the northernmost part of Kagoshima Bay, southern Kyushu, Japan. Sakurajima volcano, one of the most active volcanoes in Japan, is a post-caldera stratovolcano of the caldera. I analyzed 60 samples in total; 12 charcoal, one wood and 47 paleosol samples in the Aira caldera and its surroundings. Paleosol samples are available more easily and systematically than charcoal or wood samples. In addition, I focused particularly on non-disturbed tephra layers which implied good depositional conditions of the paleosol layers immediately below the tephra layers (i.e., continuity of soil accumulation and non-disturbance of paleosols), because the tephra layers covering the paleosol layers work as a barrier to prevent vertical movement of soil organic matter. Their ^<14>C dates are consistent with stratigraphical relationship among them. Therefore, ^<14>C dates of paleosol samples represent the time then the tephra layer covered the paleosol, namely, its eruption age. C/N ratio of humin fraction from paleosol sample is a promising indicator for detecting possible sample contamination from allochthonous organic materials. On the basis of these ^<14>C dates, I restored a well-constrained eruptive history of the Aira caldera during the last 30,000 years. Since the Otsuka eruption of 30ka, at least four major pyroclastic eruptions (0,1km^3 to 1.5km^3 in bulk volume for each tephra) occurred intermittently in the eastern part of Aira caldera until 25ka. At 24.5ka, a series of large-scale eruptions (>411km^3 in bulk volume), referred to the AT eruption, occurred. Sakurajima volcano started eruption at 22.5ka. The Old Kita-dake stage of this volcano lasted until 20ka. During the dormant period between the Old and Young Kitadake stages, the Takano base surge was erupted from the eastern part of the Aira caldera at 16ka. After 9000 years of quiescence of Sakurajima volcano, the Young Kita-dake stage started with the Satsuma eruption at 11ka. This stage continued from 11ka to 3.5ka with quasi-periodic activity of an 800-2000 year recurrence interval. Several well-known historical eruptions in the Minami-dake stage followed it. The calendar age rages calibrated dendro-chronologically from ^<14>C dates for these eruptions agree with their calendar dates, based on the historical documents. Thus, these ^<14>C dates provide chronological constraints for correlating tephra layers with the historical records., タンデトロン加速器質量分析計業績報告 Summaries of Researches Using AMS 1996 (平成8)年度},
 pages = {183--221},
 title = {Accelerator Mass Spectrometric Radiocarbon Chronology during the Last 30,000 Years of the Aira Caldera, Southern Kyushu, Japan},
 volume = {8},
 year = {1997}
}