@article{oai:ishikawa-pu.repo.nii.ac.jp:00000215,
 author = {THAPA, Prakash Singh and 半澤, 風人 and 勝見, 尚也 and KATSUMI, Naoya and 百瀬, 年彦 and MOMOSE, Toshihiko and 柳井, 清治 and YANAI, Seiji and THAPA, Prakash Singh and HANZAWA, Kazeto},
 journal = {石川県立大学研究紀要, Bulletin of Ishikawa Prefectural University},
 month = {},
 note = {In May 2021, a large-scale deep-seated landslide occurred in Hirose-town, Hakusan City, Ishikawa Prefecture in Japan. The landslide extended to an area of 1.1 hectares with a 22m deep scouring head scarp, producing approximately 86000m3 sediment. The collapsed debris flowed about 475m distance downstream, destroying the planted Cedar (Cryptomeria japonica) forest on the slope, then outspread and ultimately deposited on the alluvial terraces downstream. The landslide removed an estimated 540 Cedar trees, each with an average height of 23.3 meters. At the deposition area, it was observed that the drifted trees accumulated to create a retention dam-like structure of 8m in height which obstructed huge sediment material behind it. The leading edge of the debris flow was almost captured within the tree line, and the gap of this outflow with the rice paddy field below was approximately 25m. This study concluded that the massive debris flow that would have otherwise reached the paddy fields was prevented by two factors: (a) the mature Cedar forest, which developed a resistive force that halted the energy of the debris flow, and (b) a natural retention dam-like structure formed by driftwood obstructed along the standing trees, which trapped numerous debris. Therefore, the findings of this research will enhance our understanding of the preventive functions of trees against debris flow in hillslopes., 2021年5月石川県白山市広瀬町で大規模な深層崩壊が発生した。そこでLiDARデータ，現地測量データおよびドローンを用い，深層崩壊の実態を解析した。その結果，崩壊源の深さは約22m，崩壊面積は約11,000m2，生産土砂量は約86,000m3であった。崩壊斜面周辺には線状凹地とリニアメントが発達しており，地下水位が上昇するのに時間を要したため，先行降雨から78 時間後に崩壊が発生したと考えられた。崩壊土砂は流下する過程で土石流となり斜面上のスギ林を破壊しながら約475m流下した後，沖積錐上に拡散堆積した。土石流の末端では流木が約8mの厚さでダムアップし，背後に多量の土砂を貯留して停止していた。土石流の流出が抑制された要因として，スギ人工林の引き倒し抵抗モーメントによる減勢と流木ダムによる貯留効果が考えられた。},
 pages = {1--13},
 title = {Characteristics of Deep-seated Landslide and Debris-flow Prevention Function of Cedar Forest -Learnings from Hirose Landslide, Ishikawa Prefecture, Japan-},
 volume = {6},
 year = {2023},
 yomi = {THAPA, Prakash Singh and ハンザワ, カゼト and カツミ, ナオヤ and モモセ, トシヒコ and ヤナイ, セイジ}
}