[SVC47-P31] Pyroclastic flow deposit of the 2015 Kuchinoerabujima Volcano
Keywords:volcano, eruption, pyroclastic flow , Kuchinoerabujima Volcano, phreatomagmatic eruption
We surveyed the distribution and sequence of the PDC deposit and thermal and mechanical damages by the PDC within the area of PDC. The thermal damage was remarkable in the upper part of the trees which were directly exposed to the PDC. The thermal damage on the trees were limited within the area of PDC. No thermal damage was recognized in the area where was covered by the ash fall from the PDC. The nylon items in the PDC deposit were partially melted. The thickness of the deposit at the end of the PDC area in Mukaehama was less than 5 cm. The deposit shows remarkable normal-grading from lapilli and very-coarse sand at the base to very-fine sand at the top. At the base of the deposit, lapilli ~1.5 cm in diameter were found. Many plant fragments in the deposit tell the strong flow which destroyed the forest along its pass. These observations indicate that the deposit was formed by a short and single-pulse PDC with high velocity. This is consistent with the visual observations by some monitoring cameras.