Abstract
In the last few years, small unmanned aerial vehicles (UAVs) and structure-from-motion multi-view stereo (SfM-MVS) photogrammetry have attracted a tremendous amount of interest for the creation of high-definition topographic data. This study detected spatial distributions of shallow landslides and their sediment yields using small UAVs and SfM-MVS photogrammetry. The study areas were the Saishigahana area (0.06km2) and the Sensuikyo area (1.00km2) at Aso Volcano, Japan, where many shallow landslides occurred due to heavy rainfall in July 2012.
We obtained ortho-rectified photographs with spatial resolutions of 0.04, and digital surface models (DSMs) with spatial resolutions of 0.10 and 0.16m. In the Saishigahana area, 26 landslides (19.87–4,593.85m2) occurred. The ratio of the total landslide area was 30% of the area. The estimated sediment yield reached 4.84 (±0.37)×105m3/km2. In the Sensuikyo area, 378 landslides (8.74–6,162.23m2) occurred. The estimated total landslide volume was 1.22 (±0.21)×105m3/km2. These sediment yields were 10 times greater than reported after the past rainfall-induced landslide events in the area. Our results demonstrated the potential sediment yields due to a single rainfall event at Aso Volcano.
