AMS radiocarbon dates of pyroclastic-flow deposits on the southern slope of the Kuju Volcanic Group, Kyushu, Japan

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

We present here results of AMS C dating to refine the history of the middle and western parts of the Kuju Volcanic Group, located in middle Kyushu, Japan, which consists of more than 20 lava domes and cones. C dating has conducted by AMS (JAEA-AMS-TONO) under the Common-Use Facility Program of JAEA. The Handa PF deposits, which are products of the largest eruption of the group, were dated to 53.5 ka BP. The Shirani and Muro PF deposits, which are block-and-ash flows, were dated to 44 to 50 cal ka BP and 3539 cal ka BP, respectively. These ages can be correlated with the TL ages for the lava domes. Therefore, both TL and C methods can be useful tools in establishing the eruptive sequence of lava domes and pyroclastic flows. This study also demonstrates that these eruptive activities occurred after the Handa pfl, the biggest eruption during the last 150 kyrs without a significant time interval.