Radiocarbon dating of pyroclastic flows in the middle parts of Kuju Volcano, Kyushu, Japan

Okuno, Mitsuru*; Nagaoka, Shinji*; Kokubu, Yoko   ; Nakamura, Toshio*; Kobayashi, Tetsuo*

Kuju volcano, located between Aso and Yufu-Tsurumi volcanoes in middle Kyushu, Japan, consists of more than 20 eruptive centers. We present here results of AMS radiocarbon dating to refine the history of the middle and western parts of Kuju volcano taking in the ages of Thermoluminescence (TL) dating. Radiocarbon ages for pyroclastic flows of Handa, Shirani and Muro on the southern sector of the volcano were ca. 30 - 50 kBP. These dates can be correlated with the TL ages for the lava domes. These results shows the lava domes formed relatively constant and the pyroclastic flows ran down toward the base of the volcano after the pyroclastic flow of Handa. Eruptions released at different periods are difficult to distinguish each other because their petrographical features are similar. Therefore, both TL and radiocarbon dating methods can be useful tools in establishing the eruptive sequence of lava domes and pyroclastic flows.