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Affiliation |
Faculty of Agriculture Department of Forest and Environmental Sciences |
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Associate Professor |
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External Link |
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SHINOHARA Yoshinori
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Research Areas 【 display / non-display 】
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Social Infrastructure (Civil Engineering, Architecture, Disaster Prevention) / Disaster prevention engineering
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Life Science / Forest science
Papers 【 display / non-display 】
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Park J.H., Shinohara Y., Gomez C., Hotta N.
Geomorphology 453 2024.5
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Geomorphology
Rainfall-triggered volcanic debris flows (VDFs), or lahars, frequently occur during and/or immediately after eruptions, often because of decreases in the infiltration capacity resulting from the deposition of fine volcanic materials. Although the infiltration capacity recovers and the frequency of VDFs decreases within a decade, VDFs have continued to occur over several decades after the eruption of some volcanoes. No study has yet identified the factors controlling sediment discharge of VDFs for a specific volcano after the recovery of infiltration capacity to the pre-eruptive level. We analyzed topographic changes and sediment volumes between 2003 and 2020, using 16 digital elevation models (DEMs) and orthophotographs from aerial lidar scanning for the Tansandani and Gokurakudani gullies of Mount Unzen where the infiltration capacity has recovered after the most recent eruption in 1990–1995. We also analyzed the frequency and magnitude of VDFs in 2003–2020. Topographic changes differed before and after three large-scale VDFs in 2015 and 2016. The total volume of the three VDFs was 140 × 103 m3. Between 2003 and 2014, the width and depth of the gullies continuously increased, with the changes in the intervals of successive DEMs averaging below 5 m. Between 2017 and 2020, gully cross-sections remained U-shaped and changed little, while the channel gradient gradually decreased. U-shaped gullies promote the dispersion of VDFs and their gentle slopes reduce the velocity of VDFs. As a result, the frequency and magnitude of VDFs decreased, and deposition and erosion in the gullies were almost balanced between 2017 and 2020. Thus, we conclude that topography is the main factor that controls the occurrence and magnitude of debris flows and therefore sediment discharge after the recovery of infiltration capacity to the pre-eruptive level.
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Daikai R., Gomez C., Hotta N., Shinohara Y.
IOP Conference Series: Earth and Environmental Science 1314 ( 1 ) 2024.3
Publishing type：Research paper (international conference proceedings) Publisher：IOP Conference Series: Earth and Environmental Science
As climate change creeps into the 21st century, the intensity of debris flows due to heavy and concentrated rainfall has increased in mountainous regions of Japan and East Asia. However, the relationship between climate change and an increase in debris flows is likely to be non-linear. Rainwater infiltrates more quickly into porous material, and the lack of vegetation cover increases evaporation and the temperature of surface sediments. In addition, periodic gully collapses bring fresh layers of porous material that increase the distance between the surface and the vadose zone. Therefore, to understand the relationship between volcanic debris flows (or lahars), parameters such as density, porosity, temperature, and moisture retention must be captured in detail in both time and space. The aim of this paper is to assess the role of loose, coarse, and porous sediments in lahar triggering. The present study was conducted at Unzen volcano in the Tansandani Guly between 31 May and 1 June 2023, 30 years after the last eruption. The dacite material is composed of a matrix of sand and coarse sand mixed with larger fractions and blocks, therefore traditional density measurement methods could not be applied, and a photogrammetric based method was used. In the field, sets of SfM-MVS photographs were taken before and after digging a hole in the sediments so that the measured mass could be compared to the volume of the hole in the sediments. After the sediments were dried, the dry and wet density, bulk density and porosity of the sample were calculated. When compared to the temperature data collected in the field, the following results were obtained: (1) The porosity of the volcanic material was highest in the lower reaches, followed by the upper reaches, and lowest in the middle reaches. This may be because fine sand washed out of the upstream area by rainfall is currently stored in the midstream area, which may facilitate debris flow generation. In addition, the downstream area has a high porosity, which may be due to the surrounding vegetation preventing the influx of new fine sand from the channel wall. (2) Because of the higher porosity and the lack of organic matter and vegetation cover, the increase in temperature acts more directly on the decrease in water content than in mountainous areas. Consequently, empirical equations for the potential for mudslides in volcanic areas with respect to surface temperature and soil moisture need to be developed for hazard and disaster risk management purposes.
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Short communication: Concentrated impacts by tree canopy drips – hotspots of soil erosion in forests Reviewed International coauthorship
Katayama A., Nanko K., Jeong S., Kume T., Shinohara Y., Seitz S.
Earth Surface Dynamics 11 ( 6 ) 1275 - 1282 2023.12
Language：English Publishing type：Research paper (scientific journal) Publisher：Earth Surface Dynamics
The degradation of ground vegetation cover caused by large grazing herbivores frequently results in enhanced erosion rates in forest ecosystems. Splash erosion can be caused by drop impacts with a high throughfall kinetic energy (TKE) from the tree canopy. Notably larger canopy drips from structurally mediated woody surface points appear to induce even higher TKE and generate concentrated impact locations causing severe focus points of soil erosion. However, TKE at these locations has rarely been reported. This pilot study investigated the intensity of TKE at a concentrated impact location and compared it with general TKE locations under the canopy and freefall kinetic energy (FKE) outside the forest. We measured precipitation, TKE and FKE using splash cups at seven locations under Japanese beech trees and five locations outside the forest during the leafless and leafed seasons in 2021 in a mixed forest with evergreen coniferous trees and deciduous broadleaved trees in Japan. The TKE at the concentrated impact location was 15.2 and 49.7 times higher than that at the general locations under the beech and FKE, respectively. This study confirmed that canopy drip from woody surfaces could be a hotspot of soil erosion in temperate forest ecosystems. Throughfall precipitation at the concentrated impact location was 11.4 and 8.1 times higher than that at general locations and freefall, respectively. TKE per 1 mm precipitation (here, “unit TKE”) at the concentrated impact location (39.2 ± 23.7 J m−2 mm−1) was much higher than that at general locations (22.0 ± 12.7 J m−2 mm−1) and unit FKE (4.5 ± 3.5 J m−2 mm−1). Unit TKE in the leafless season was significantly lower than in the leafed season because of fewer redistribution of canopy drips induced only by woody tissue. Nevertheless, unit TKE at the concentrated impact location in the leafless season (36.4 J m−2 mm−1) was still higher than at general locations in the leafed season. These results show that potentially high rates of sediment detachment can be induced not only by throughfall precipitation but also by larger throughfall drop size distributions at the concentrated impact location, even in the leafless season. Further studies with more replication building on this first report are necessary to investigate how many of these concentrated impact locations may occur on average with different tree species to better assess the extent of the erosion risk under forests.
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Differences in factors determining landslide hazards among three types of landslides in Japan Reviewed
Shinohara Y., Watanabe Y.
Natural Hazards 118 ( 2 ) 1689 - 1705 2023.9
Authorship：Lead author, Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Natural Hazards
The motivation for this study was to clarify the factors that affect landslide occurrences at the national level in Japan and differences in the factors that result from landslide types. The factors that cause differences in the number of rainfall-triggered landslide disasters in 47 Japanese prefectures were examined using generalized linear models. The analysis was conducted for each of the three types (i.e., steep-slope failure, deep-seated landslide, and debris flow) of landslide disasters. For all types, the rainfall index and the number of landslide-prone areas were selected with positive coefficients while the accretionary complexes geological type was selected with negative coefficients. For steep-slope failure, forests and land for buildings were selected with negative and positive coefficients, respectively. For deep-seated landslide and debris flow, land use was seldom selected. Thus, the factors were found to have differed as a result of the landslide type. Because the number of landslides alters the fatalities and building damage in Japan, this study contributes to the prioritization of landslide countermeasures at the national level.
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Gomez C., Hotta N., Shinohara Y., Park J.H., Tsunetaka H., Zhang M., Bradak B., Sri Hadmoko D., Budi Wibowo S., Daikai R., Yoshida M.
Journal of Applied Geophysics 209 2023.2
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Applied Geophysics
Volcanic gullies develop U-shape cross-profiles due to the lahars that shape them after eruptive events. Over time, the processes of sediment-transfer change and the erosion of sub-vertical walls become a leading process. It results in debris-cones at their foot. However, the processes that generate these landforms is still unclear. Indeed, the surface is the one of a cone or a “steep debris-fan”, but are these diffusive landforms starting through progressive regressive-erosion of the wall, or do they follow an original collapse? This we do not know, and as the material is poorly-sorted with a mixture of unconsolidated fine sands to large clasts, digging a trench is not possible as it destroys the material structure. Therefore, the present contribution aims to define the development mechanisms of the side-wall debris-cones using Ground Penetrating Radar imaging, working in the Tansandani Gully at Unzen Volcano (Japan). The GPR used in the study is a Mala Ramac Pro-Ex mounted with a 500 MHz shielded antenna. The GPR signal penetrated up to 4–5 m depth and the velocity was homogeneous on average through the different material layers and at the different location, although at depth variations occurred. The structure of the units in the radargrams present units' parallel to the surface for the first 40 to 60 cm, with underneath the presence of more irregular prograding units, with eventually underneath a set of units that are structureless and often rich in blocks. The two lower structureless-units are not always present and one of the debris-cone only showed a set of rough subparallel units. This differences are the result of the debris-cones being generated by (1) at first a wall collapse or by rapid water-borne processes creating (2) bulk prograding units, which have to be put in place during a heavy-rainfall event. Finally, near the surface, the (3) thin subparallel units are most probably post-rainfall deposition, resulting from gravity process in dry-material. This can be inferred because there is no evidence of erosion or remobilization in layers and the process has been observed in the field. For the observed debris-cones, their formation is dominated by a wall collapse, which is then recovered by finer-grained units deposited sub-horizontally to the surface.
Books 【 display / non-display 】
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森林水文学入門
篠原慶規（ Role： Contributor , 蒸発散）
朝倉書店 2022.9
Language：Japanese Book type：Textbook, survey, introduction
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森林学の百科事典
篠原 慶規（ Role： Joint author）
丸善出版 2021.1
Total pages：694 Responsible for pages：災害防止と保安林（第13章 森林と災害） Language：Japanese Book type：Dictionary, encyclopedia
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The necessity of sensor calibration for the precise measurement of water fluxes in forest ecosystems. IN Forest-Water Interactions
Shin'ichi Iida, Takanori Shimizu, Yoshinori Shinohara, Shin'ichi Takeuchi, Tomo'omi Kumagai（ Role： Joint author）
Springer Nature 2020.2
Total pages：643 Responsible for pages：519-536 Language：English Book type：Scholarly book
MISC 【 display / non-display 】
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はげ山的水源涵養機能からの脱却
篠原 慶規
森林科学 98 ( 0 ) 41 - 41 2023.6
Authorship：Lead author Language：Japanese Publishing type：Article, review, commentary, editorial, etc. (scientific journal) Publisher：日本森林学会
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The July 2020 Rainfall-Induced Sediment Disasters in Kumamoto Prefecture, Japan
JITOUSONO Takashi, SHINOHARA Yoshinori, SHIMIZU Osamu, TAGATA Satoshi, TERAMOTO Yukiyoshi, TORITA Eiji, NAGATANI Naomasa, NAKANO Koji, NISHIWAKI Ayato, HIRAKAWA Yasuyuki, FUKUZUKA Kozaburou, IGURA Mari, MIZUNO Hideaki, UE Hirotaka, OHISHI Hiroyuki, KAKIMOTO Tsuyoshi, KITOU Ken-ichi, KOGA Syozo, SAKAI Yusuke, SAKASHIMA Toshihiko
砂防学会英文誌 13 ( 4 ) 93 - 100 2021.4
Language：English Publishing type：Article, review, commentary, editorial, etc. (scientific journal) Publisher：公益社団法人 砂防学会
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.
DOI： 10.13101/ijece.13.93
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Sediment disasters in Kumamoto Prefecture by a heavy rainfall in July 2020
JITOUSONO Takashi, SHINOHARA Yoshinori, SHIMIZU Osamu, TAGATA Satoshi, TERAMOTO Yukiyoshi, TORITA Eiji, NAGATANI Naomasa, NAKANO Koji, NISHIWAKI Ayato, HIRAKAWA Yasuyuki, FUKUZUKA Kozaburou, IGURA Mari, MIZUNO Hideaki, UE Hirotaka, OHISHI Hiroyuki, KAKIMOTO Tsuyoshi, KITOU Ken-ichi, KOGA Syozo, SAKAI Yusuke, SAKASHIMA Toshihiko
Journal of the Japan Society of Erosion Control Engineering 73 ( 4 ) 41 - 50 2020
Language：Japanese Publishing type：Rapid communication, short report, research note, etc. (scientific journal) Publisher：Japan Society of Erosion Control Engineering
On July 4, 2020, heavy rainfall was observed in the southern part of Kumamoto prefecture and the northern part of Kagoshima prefecture. Due to the heavy rainfall, floods and sediment disasters such as landslides and debris flows were occurred especially in the Kuma River basin of Kumamoto prefecture. We conducted field investigations at four sites in Ashikita-town and Tsunagi-town, Kumamoto prefecture, where landslides and/or debris flows caused deaths. We also conducted field investigations in the Kawauchi River branch of the Kuma River where huge 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 in these investigations.
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Estimation of potential areas affected by large-scale sediment movements and disaster mitigations for the large-scale sediment movements Reviewed
70 ( 1 ) 20 - 30 2017.5
Language：Japanese Publishing type：Article, review, commentary, editorial, etc. (scientific journal)
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SHINOHARA Yoshinori
JOURNAL OF JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES 30 ( 2 ) 126 - 126 2017
Language：Japanese Publishing type：Article, review, commentary, editorial, etc. (scientific journal) Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES
Presentations 【 display / non-display 】
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森林の成熟が土砂災害発生に与える影響の全国的評価
篠原慶規，Novia Lusiana，今泉文寿
日本森林学会大会 2024.3.8
Event date： 2024.3.8 - 2024.3.11
Language：Japanese Presentation type：Oral presentation (general)
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高密度のマダケ林における樹冠遮断の特徴
木村健人，篠原慶規
日本森林学会大会 2024.3.8
Event date： 2024.3.8 - 2024.3.11
Language：Japanese Presentation type：Poster presentation
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宮崎大学田野フィールドの常緑広葉樹林におけ る樹冠遮断量の計測
阿部悠南，後藤君龍，高木正博，篠原慶規
日本森林学会大会 2024.3.8
Event date： 2024.3.8 - 2024.3.11
Language：Japanese Presentation type：Poster presentation
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様々な表層崩壊跡地における土層厚の回復
松永美月，竹内万結，佐藤忠道，執印康裕，久米朋宣，篠原慶規
日本森林学会大会 2024.3.8
Event date： 2024.3.8 - 2024.3.11
Language：Japanese Presentation type：Poster presentation
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What are the factors determining long-term trends in the fatality of rainfall-triggered landslides?
Shinohara Yoshinori, Kume Tomonori
2023.9.6 THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES
Event date： 2023.9.3 - 2023.9.6
Language：Japanese Presentation type：Oral presentation (general)
Awards 【 display / non-display 】
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若手農林水産研究者表彰（農林水産技術会議会長賞）
2023.11 農林水産省 森林および竹林の水土保全機能に関する研究
篠原慶規
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日本森林学会奨励賞
2017.3 日本森林学会
篠原 慶規
Award type：Award from Japanese society, conference, symposium, etc. Country：Japan
Grant-in-Aid for Scientific Research 【 display / non-display 】
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降雨は火山災害を激化させるのか：時系列データの統合・再構築に基づく山体変形解析
Grant number：23K17801 2023.04 - 2025.03
独立行政法人日本学術振興会 科学研究費補助金 基盤研究（C）
Authorship：Coinvestigator(s)
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土砂災害による死者数の時空間変動要因の解明
Grant number：21K04590 2021.04 - 2024.03
独立行政法人日本学術振興会 科学研究費補助金 基盤研究(C)
Authorship：Principal investigator
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森林から河川へ流出する炭素量は吸収量に対してどの程度の割合なのか？
Grant number：21H02238 2021.04 - 2024.03
独立行政法人日本学術振興会 科学研究費補助金 基盤研究(B)
高木 正博、
Authorship：Coinvestigator(s)
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地上計測とドローンを用いた高時空間分解能の森林蒸散量の推定
Grant number：18K14492 2018 - 2021.03
科学研究費補助金 若手研究(B)
Authorship：Principal investigator
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表層崩壊の危険性を評価する上で土壌水分の空間的不均一性は考慮する必要があるのか？
Grant number：25850109 2013.04 - 2016.03
科学研究費補助金 若手研究(B)