5:15 PM - 6:30 PM
[HDS10-P05] Surface changes of rock slopes in the Hakuba-Daisekkei Valley, northern Japanese Alps
Keywords:rockfall, rock slope failure, SfM, UAV, freezing and thawing, ICP
Introduction
In the northern Japanese Alps, rock slope failure has caused mountaineering accidents frequently. In Hakuba-Daisekkei Valley, rock slope failure with victims occurred in 2005 (Kariya, 2006). However, the process and geomorphological characteristics of rock slope failure are unclear. As a reason, it is difficult to investigate the steep rock slope directly. The purpose of this study is to clarify the process of rock slope failure on different rock types in Hakuba-Daisekkei Valley using UAV and SfM methods.
Study area
Hakuba-Daisekkei is a perennial snow patch located at the bottom of the Hakuba-Daisekkei Valley. The valley is a popular mountaineering route to Mt. Hakuba-dake (2932 m asl). More than 10,000 people pass the route every year. Hakuba-Daisekkei Valley is surrounded by Mts. Shakushi-dake and Hakuba-dake. Mt. Hakuba consisted of felsic tuff and tuff breccia. Mt. Shakushi consisted of Felsite. Hakuba-Daisekkei Valley is high annual precipitation through summer and heavy snow climate in Japan.
Methods
We observed the retreat process of rock slopes using images of UAV, Cessna and aerial photography with SfM (Structure from Motion) technology.
Results
We confirmed the difference in the retreat process between Mt. Shakushi-dake and Mt. Hakuba-dake. On the rock slope of Mt. Shakushi-dake, we observed the discriminatory retreat that depended on rock joint density. On the other side, we observed the sudden retreat process with a tension crack opening on the rock slope of Mt. Hakuba-dake.
In the northern Japanese Alps, rock slope failure has caused mountaineering accidents frequently. In Hakuba-Daisekkei Valley, rock slope failure with victims occurred in 2005 (Kariya, 2006). However, the process and geomorphological characteristics of rock slope failure are unclear. As a reason, it is difficult to investigate the steep rock slope directly. The purpose of this study is to clarify the process of rock slope failure on different rock types in Hakuba-Daisekkei Valley using UAV and SfM methods.
Study area
Hakuba-Daisekkei is a perennial snow patch located at the bottom of the Hakuba-Daisekkei Valley. The valley is a popular mountaineering route to Mt. Hakuba-dake (2932 m asl). More than 10,000 people pass the route every year. Hakuba-Daisekkei Valley is surrounded by Mts. Shakushi-dake and Hakuba-dake. Mt. Hakuba consisted of felsic tuff and tuff breccia. Mt. Shakushi consisted of Felsite. Hakuba-Daisekkei Valley is high annual precipitation through summer and heavy snow climate in Japan.
Methods
We observed the retreat process of rock slopes using images of UAV, Cessna and aerial photography with SfM (Structure from Motion) technology.
Results
We confirmed the difference in the retreat process between Mt. Shakushi-dake and Mt. Hakuba-dake. On the rock slope of Mt. Shakushi-dake, we observed the discriminatory retreat that depended on rock joint density. On the other side, we observed the sudden retreat process with a tension crack opening on the rock slope of Mt. Hakuba-dake.