[O02-P74] Flood sediments in the Jomon period buried in the Kashikawa lowland formed by the Tachikawa fault
Keywords:Kasumigawa, Tachikawa fault, Jomon Period
The Kasumigawa flowing on the Musashino fan from west to east crosses the Tachikawa fault on the way. The Tachikawa fault is an active fault that continues northwest - southeast and the northeast side rises. Upstream of the Kasumigawa was blocked by the past faulting activity and a basin-like flat terrain spreads out. Drilling down a few meters by repair work of Kasumigawa, a stratum cross section including many pieces of earthenware and pieces of plants appeared. The earthenware fragments have Feathered Jomon sentences, Parallel squatting sentences, Embossed sentences, Yamagata stamped sentences and so on and they are obviously of the Jomon period. Plant pieces also contain a large amount of Tochi, Onigurumi, Nara and Oak young fruit and shellfish. From these facts, it was found that the flood occurred in the early autumn of the Jomon Period and the sedimentation occurred. We estimate that the activity of the Tachikawa fault was in the vicinity of this period.