| 1. |
Takashi JITOUSONO, Mari IGURA, Hirotaka UE, Hiroyuki OHISHI, Tsuyoshi KAKIMOTO, Ken-ichi KITOU, Syozo KOGA, Yusuke SAKAI, Toshihiko SAKASHIMA, Yoshinori SHINOHARA, Osamu SHIMIZU, Satoshi TAGATA, Yukiyoshi TERAMOTO, Eiji TORITA, Naomasa NAGATANI, Koji NAKANO, Ayato NISHIWAKI, Yasuyuki HIRAKAWA, Kozaburou FUKUZUKA, Hideaki MIZUNO, The July 2020 Rainfall-Induced Sediment Disasters in Kumamoto Prefecture, Japan, International Journal of Erosion Control Engineering, https://doi.org/10.13101/ijece.13.93, 14, 4, 93-100, 2021.04, On July 4, 2020, heavy rainfall was observed in the southern part of Kumamoto Prefecture and the northern part of Kagoshima Prefecture. Due to heavy rainfall, floods and sediment disasters such as collapses and debris flows occurred predominantly in the Kuma River basin of Kumamoto Prefecture. We conducted field investigations at four sites in Ashikita Town and Tsunagi Town, Kumamoto Prefecture, where collapses and debris flows caused deaths. We also conducted field investigations in the Kawauchi River branch of the Kuma River, where vast amounts of sediment discharge caused damage to houses. The objectives of these investigations were to clarify the situation and mechanism of the disasters and to propose procedures to recover from the disasters. This report briefly summarizes the results of these investigations.. |
| 2. |
Process and mechanism of sedimentation in a conduit. |
| 3. |
Atsuhisa Yano, Yoshinori Shinohara, Haruka Tsunetaka, Hideaki Mizuno, Tetsuya Kubota, Distribution of landslides caused by heavy rainfall events and an earthquake in northern Aso Volcano, Japan from 1955 to 2016, Geomorphology, 10.1016/j.geomorph.2018.11.024, 327, 533-541, 2019.02, A new landslide cannot form until the soil has recovered to the critical depth for the recurrence of a landslide through the weathering of bedrock and soil transportation from adjacent areas. In volcanic areas with tephra deposits, landslides expose tephra and not bedrock. Therefore, the immunity of landslides in volcanic areas may be different from that of landslides in non-volcanic areas. Herein, we developed landslide inventory maps (LIMs) for 6 periods during 1955–2016 using aerial photographs and digital elevation models in northern Aso Volcano. In this area, landslides were found to continuously occur due to rainfall events and a large earthquake. Using the 6 LIMs, we examined the terrain attributes (i.e., slope angle, slope aspect, and normalized distance to ridge) and the overlap of landslides. Among the terrain attributes, slope angle was a dominant factor affecting the occurrence of landslides caused by both rainfall events and an earthquake. The total landslide areal density in 2016 was 50% for a slope angle of 35%–45%. 2 atypical events (a rainfall in July 2012 and an earthquake in April 2016) caused landslides to occur on slopes that were relatively resistant to landslides by typical amounts of rainfall, resulting in high landslide density in 2016. The intensity of rainfall for an event in July 2012 was considerably higher than that for other rainfall events. The type of landslides caused by an earthquake in April 2016 was different from that of landslides caused by rainfall. The depths of some landslides caused by this earthquake were deeper than those of landslides caused by the rainfall in July 2012. The overlap ratio was |
| 4. |
Andang Suryana Soma, Tetsuya Kubota, Hideaki Mizuno, Optimization of causative factors using logistic regression and artificial neural network models for landslide susceptibility assessment in Ujung Loe Watershed, South Sulawesi Indonesia, Journal of Mountain Science, 10.1007/s11629-018-4884-7, 16, 2, 383-401, 2019.02, Landslide susceptibility maps (LSMs) play a vital role in assisting land use planning and risk mitigation. This study aims to optimize causative factors using logistic regression (LR) and an artificial neural network (ANN) to produce a LSM. The LSM is produced with 11 causative factors and then optimized using forward-stepwise LR (FSLR), ANN, and their combination (FSLR-ANN) until eight causative factors were found for each method. The ANN method produced superior validation results compared with LR. The ROC values for the training data set ranges between 0.8 and 0.9. On the other hand, validation with the percentage of landslide fall into LSM class high and very high, ANN method was higher (92.59%) than LR (82.12%). FSLR-ANN with nine causative factors gave the best validation results with respect to area under curve (AUC) values, and validation with the percentage of landslide fall into LSM class high and very high. In conclusion, ANN was found to be better than LR when producing LSMs. The best Optimization was combination of FSLR -ANN with nine causative factors and AUC success rate 0.847, predictive rate 0.844 and validation with landslide fall into high and very high class with 91.30%. It is an encouraging preliminary model towards a systematic introduction of FSLR-ANN model for optimization causative factors in landslide susceptibility assessment in the mountainous area of Ujung Loe Watershed.. |
| 5. |
Hideaki Mizuno, Tetsuya Kubota, Takashi JITOUSONO, Yoshiaki NAGAI, Osamu Shimizu, Yasuhiro NOMURA, Yamato SUZUKI, Takao YAMAKOSHI, Takashi KOI, Hiroyuki OHISHI, Yasuyuki HIRAKAWA, The overview of the Yabakei landslide occurred on April 11th 2018 in Nakatsu city, Oita prefecture, Japan, International Journal of Erosion Control Engineering, 10.13101/ijece.11.36, 11, 2, 36-37, 2018. |
| 6. |
Study on the estimation of snowmelt due to pyroclastic material considering enthalpy of evaporation. |
| 7. |
Numerical model for estimating period of disaster response. |
| 8. |
Hideaki Mizuno, Takashi Sekine, Chikako Eto, Kazumasa Kuramoto, Reproduction of a Surge in a Reservoir by Using Finite Volume Method With Conservation Property, Transaction of the Japan Society for Simulation Technology, 10.11308/tjsst.8.13, 8, 1, 13-20, 2016, Recently the numerical simulation plays an important part in the emergency management for sediment-related disaster. Water and sediment go down streams that have conjunctions, curves, narrow and wide parts, so that the numerical simulation has to treat the complex geometry. Moreover, it is necessary for the numerical simulation to be applied for not only very fast flows such as debris flows and floods but also very slow flows such as still water. The numerical simulation needs to be based on unstructured mesh and to be improved in order to handle very slow flow such as still water. This study aims to develop a numerical model for still water and to verify the numerical model by reproducing the experimental results. In the developed numerical model, it is assumed that the averaged gradient of flow surface is equal to the resultant force of the hydrostatic force acting on the boundaries of element. It is found that the numerical simulation with the developed numerical model can reproduce the still water and the surges triggered by the flow going into the reservoir.. |
| 9. |
Extraction Methods of Areas Tending to Cause Deep-seated landslides. |
| 10. |
Sediment Movement and Transportation. |
| 11. |
Numerical simulation of varied flow at confluence and curved channel by using unstructured grids. |
| 12. |
Investigation into characteristics of debris flows in Funaishi Torrent occurred in July 2010. |
| 13. |
Study on structural measures for reducing disaster risk of natural lake formed by natural barrier. |
| 14. |
Assessment of disaster risks emerged by sudden breaches of landslide dams formed by the 2008 Iwate-Miyagi Nairiku Earthquake. |
| 15. |
Basic study on sediment rate measurement with a hydrophone on the basis of sound pressure data. |
| 16. |
Study on structural measures for reducing disaster risk of natural lake formed by natural barrier. |
| 17. |
Observation of sediment transport after large-scaled landslides at Mt. Wanitsukayama. |
| 18. |
Development of support system for establishment of comprehensive sediment management plan. |
| 19. |
10. Collection of suspended sediment in mountainous watershed covered by devastated forest plantations and estimation of the suspended sediment sources using environmental isotopes(Abstracts of Papers Presented at the Spring Meeting of the Union, May 2005). |
| 20. |
Experimental study on a estimating method for velocity of debris flow in bending curves. |
| 21. |
Sediment related disasters caused by heavy rainfalls in Niigata, Fukui and Tokushima in July and August 2004 (prompt report). |
| 22. |
The debris flow disasters caused by localized rainfall of seasonal rain front in Kyushu region in July, 2003 (prompt report). |
| 23. |
Measures for debris flow in the 1998's Sarno disaster area. |
| 24. |
Study on forecasting hydrograph of mudflow passing through a slit dam. |
| 25. |
Study on effectiveness of reducing peak discharge of muddy debris flow with open type dams. |
| 26. |
DEVELOPMENT OF DEBRIS FLOW SIMULATION WITH DEM METHOD. |
| 27. |
Laws and administrative organizations for preventing sediment-related disasters in Italy. |
| 28. |
Experimental Study on Controlling Debris Flow by a Consecutive Series of Open Type Steel Dams. |
| 29. |
Analysis of Simulating Debris Flow Captured by Permeable Type Dam using Distinct Element Method. |
| 30. |
Actual State fo Debris Flows Induced by Deep-seated Slope Failure on July 10, 1997 at the Harihara River Basin, Kagoshima Prefecture, Japan. |
| 31. |
Developing of Debris Flows Prediction and Deteetion Technology, Their Future Issues. |
| 32. |
Experimental Study of a Grid Dam with Narrow Pipe Interval of Upper Grids. |
| 33. |
Control of Passing Sediment with Grid-type Dams. |
