3:30 PM - 5:00 PM
[MIS10-P06] Movement of rock debris at the northern slope of Mt. Syakushi in the northern Japanese Alps.
The debris flow was caused by heavy rainfall on 23 August 2013(Jogasaki et al., 2014). In this area, there is a possibility of causing a debris flow again because debris production occurs annually.
However, the sediment transport cycle concerning the amount of erosion and deposition in this valley is not clarified.
We investigated changes in the amount of scour and deposition on the rock slopes using aerial laser data and Cessna aerial photography, which has been conducted since 2015.
The results show that a large amount of debris was deposited at the base in 2011-2012. In other years, debris ejections occurred frequently, and the amount of debris deposited was not as large as in 2011-2012.
We confirmed that a large amount of debris was deposited at the base in 2011-2012. Although debris deposition was observed during the observation periods other than 2011-2012, the amount of debris deposition was much lower than the amount of debris in 2011-2012. Based on the above, it is inferred that a large-scale rock fall occurred in 2011-2012 and that the debris flow of August 23, 2013, was caused by the sediments of this large-scale fall.
However, the sediment transport cycle concerning the amount of erosion and deposition in this valley is not clarified.
We investigated changes in the amount of scour and deposition on the rock slopes using aerial laser data and Cessna aerial photography, which has been conducted since 2015.
The results show that a large amount of debris was deposited at the base in 2011-2012. In other years, debris ejections occurred frequently, and the amount of debris deposited was not as large as in 2011-2012.
We confirmed that a large amount of debris was deposited at the base in 2011-2012. Although debris deposition was observed during the observation periods other than 2011-2012, the amount of debris deposition was much lower than the amount of debris in 2011-2012. Based on the above, it is inferred that a large-scale rock fall occurred in 2011-2012 and that the debris flow of August 23, 2013, was caused by the sediments of this large-scale fall.