{"created":"2023-05-15T09:46:00.694472+00:00","id":7368,"links":{},"metadata":{"_buckets":{"deposit":"49e525a0-5af2-49ae-ba4e-4705aece8eba"},"_deposit":{"created_by":11,"id":"7368","owners":[11],"pid":{"revision_id":0,"type":"depid","value":"7368"},"status":"published"},"_oai":{"id":"oai:kagawa-u.repo.nii.ac.jp:00007368","sets":["13:41"]},"author_link":[],"item_10006_date_granted_11":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"2021-03-24"}]},"item_10006_degree_grantor_9":{"attribute_name":"学位授与機関","attribute_value_mlt":[{"subitem_degreegrantor":[{"subitem_degreegrantor_language":"ja","subitem_degreegrantor_name":"香川大学"},{"subitem_degreegrantor_language":"en","subitem_degreegrantor_name":"Kagawa University"}],"subitem_degreegrantor_identifier":[{"subitem_degreegrantor_identifier_name":"16201","subitem_degreegrantor_identifier_scheme":"kakenhi"}]}]},"item_10006_degree_name_8":{"attribute_name":"学位名","attribute_value_mlt":[{"subitem_degreename":"博士（工学）","subitem_degreename_language":"ja"}]},"item_10006_description_7":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"近年，集中豪雨による土砂災害が多発し，多大な被害が出ている．最近では，線状降水帯にみられるような，局所的で急激な降雨形態により，集団発生的な斜面崩壊も頻発している．財政的な制約もあり，全ての危険箇所にこれらハード対策施設を整備することは，経済的・時間的に困難である．そのため，ソフト対策の推進が今後ますます重要となってくる．土砂災害の発生条件や危険度，被害の重要度は地域によって異なるため，防災・減災対策や自助・共助・公助体制といったソフト対策を進めるにあたっては，地域特性に沿った内容とする必要がある．","subitem_description_language":"ja","subitem_description_type":"Abstract"},{"subitem_description":"降雨による土砂災害の被害を軽減するにはためには，土砂災害が「どこで発生するのか（場所）」，「いつ頃発生するのか（時間）」を予測できることが理想である．","subitem_description_language":"ja","subitem_description_type":"Abstract"},{"subitem_description":"本研究では，斜面崩壊・土石流といった突発的に発生するためにその予測が困難である土砂災害を対象に，災害発生の素因に着目し，「谷密度」という地形量を指標とした予測手法を開発することで，土砂災害発生の場所と時間を予測し，被害軽減のためのソフト対策，警戒・避難判断における一手段となる方法として提案したものである．","subitem_description_language":"ja","subitem_description_type":"Abstract"},{"subitem_description":"検討に先立ち，谷密度のみを変数とする簡便な評価手法について，その有効性，適用性を検証した．谷密度計測のための谷線はコンターの平均曲率（H）から求めた．そこで，平均曲率の閾値をH=0.10とすると，一部に凹地が残るものの，谷線の連続性は比較的良く，1次谷の再現性も高くなることを確認した．","subitem_description_language":"ja","subitem_description_type":"Abstract"},{"subitem_description":"次に，既往の土砂災害を対象に，災害発生流域の谷密度と斜面崩壊発生頻度を比較した．両者の間には良い相関が見られ，谷密度が増加するにつれて，崩壊密度も増加する傾向が認められた．また，谷密度と崩壊密度との関係を見る場合は，解析対象とする流域の面積が，2.0km²以下であることが望ましいことが明らかになり，解析領域を考慮すれば，谷密度は流域スケールでの土砂災害発生の危険度が高い「場所（地域）」を評価する有効な指標になり得ると考えられる．","subitem_description_language":"ja","subitem_description_type":"Abstract"},{"subitem_description":"同様に，斜面崩壊の時刻歴が把握されている土砂災害について，災害発生時の雨量指標R’を推定し，谷密度と比較した．結果，斜面崩壊・土石流は，雨量指標R’が250mmを越えてから発生することが明らかになった．斜面崩壊の主誘因である雨量指標R’と谷密度との関連性は高く，これら雨量指標と組み合わせることで，より確度の高い土砂災害発生時間の予測も可能になるとした．","subitem_description_language":"ja","subitem_description_type":"Abstract"},{"subitem_description":"これらの検討・検証の結果，谷密度を指標とする評価手法が，土砂災害発生危険度の高い場所，時間を予測できる方法であると結論付けた．その上で，特異な地質構造にある地域や，地すべり地域へ適用する際には留意を要するなど，本手法の適用条件（適用限界）も示した．最後に，今度の展望として，土砂災害発生基準線の設定や既存の土砂災害ハザードマップの情報の高度化など，本手法の利活用を提案した．","subitem_description_language":"ja","subitem_description_type":"Abstract"},{"subitem_description":"Drainage density exhibits spatial characteristics that provide important information about the nature of the drainage basin. For example, permeability of the bedrock, ground-water movement, infiltration capacity of the soil mantle, surface-water discharge, erodibility of the surface materials. These characters represent the dominant factors that affect to frequency of slope failure, landslide and debris flow. And mainly incentive of slope failure is rainfall. The rainfall intensity is proportional to the susceptibility of slope failure occurrence. The authors investigated the relationship between drainage density and rainfall index, through the past disasters in southwest Japan. The drainage density of occurred debris flows are higher than the basin of occurred landslide. And the rainfall intensity leading to slope failures are higher than debris flows. Drainage density would be good index for evaluation of susceptibility that rainfall-induced landslide, slope failure and debris flow in small catchment area.","subitem_description_language":"en","subitem_description_type":"Abstract"}]},"item_10006_dissertation_number_12":{"attribute_name":"学位授与番号","attribute_value_mlt":[{"subitem_dissertationnumber":"甲第145号"}]},"item_10006_version_type_18":{"attribute_name":"著者版フラグ","attribute_value_mlt":[{"subitem_version_resource":"http://purl.org/coar/version/c_970fb48d4fbd8a85","subitem_version_type":"VoR"}]},"item_access_right":{"attribute_name":"アクセス権","attribute_value_mlt":[{"subitem_access_right":"open access","subitem_access_right_uri":"http://purl.org/coar/access_right/c_abf2"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"木下, 博久","creatorNameLang":"ja"},{"creatorName":"キノシタ, ヒロヒサ","creatorNameLang":"ja-Kana"},{"creatorName":"Kinoshita, Hirohisa","creatorNameLang":"en"}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2021-05-18"}],"displaytype":"detail","filename":"Eng_A145.pdf","filesize":[{"value":"30.7 MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"本文","objectType":"fulltext","url":"https://kagawa-u.repo.nii.ac.jp/record/7368/files/Eng_A145.pdf"},"version_id":"7a6c53f7-3a7d-46c3-b80e-1293137b2295"},{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2021-05-18"}],"displaytype":"detail","filename":"Eng_A145_abstract_result.pdf","filesize":[{"value":"352.3 kB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"論文内容の要旨・審査結果の要旨","objectType":"abstract","url":"https://kagawa-u.repo.nii.ac.jp/record/7368/files/Eng_A145_abstract_result.pdf"},"version_id":"21b492ba-be86-43eb-b240-bbf981ab3321"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"jpn"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"doctoral thesis","resourceuri":"http://purl.org/coar/resource_type/c_db06"}]},"item_title":"谷密度を活用した流域別土砂災害危険度評価手法の開発","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"谷密度を活用した流域別土砂災害危険度評価手法の開発","subitem_title_language":"ja"},{"subitem_title":"Drainage density and rainfall intensity as slope failure susceptibility index in small catchment area","subitem_title_language":"en"}]},"item_type_id":"10006","owner":"11","path":["41"],"pubdate":{"attribute_name":"PubDate","attribute_value":"2021-05-18"},"publish_date":"2021-05-18","publish_status":"0","recid":"7368","relation_version_is_last":true,"title":["谷密度を活用した流域別土砂災害危険度評価手法の開発"],"weko_creator_id":"11","weko_shared_id":-1},"updated":"2024-10-31T08:03:38.661365+00:00"}