日本の国土と土砂災害の実態 Land of Japan and Sediment-related disaster
description
Transcript of 日本の国土と土砂災害の実態 Land of Japan and Sediment-related disaster
日本の国土と土砂災害の実態Land of Japan and Sediment-relat
ed disaster
日本の国土の特徴Feature of the Land of Japan
• 大陸プレートと海洋プレートの境界部に位置する島弧 Island arc located on the boundary of continental plate and ocean plate
• 地形が急峻な山地が大半 Steep mountainous area • 地質が複雑 Complex Geology• 火山が多い Many volcanoes• 地震が多い Many earthquakes• 降水量が多い(梅雨、台風、
降雪等) Much rainfall (supplied by rain front (Baiu front), typhoon and snow)
• 土砂災害の発生が多い Many sediment-disasters
日本での土砂災害発生件数Number of sediment-disaster in Japan
1996
(出典:国土交通省砂防部ホームページ)( From the homepage of the Ministry of Land, Infrastructure and Transport )
1997 1998 1999 2000 2001( 1996 ~ 2000) 平均 year
Slope failureLandslide
Debris flow
Number of disaster
日本の土砂災害危険箇所数Number of sediment-disaster hazard zone in Japa
n• 土石流危険渓流数
Number of debris flow hazard streams : 79,318 (in 1993)• 地滑り危険箇所数
Number of landslide hazard zones : 11,288 (in 1998)• 急傾斜地崩壊危険箇所数
Number of slope failure hazardous places : 86,651 (in 1997)
• 全危険箇所についてハード対策(構造物による対策)を実施するのは困難である It is difficult to implement ‘hard’ mitigation measures (structural mitigation) in all hazard zones.
• 観測と警戒避難 ( ソフト対策 ) が重要 Monitoring, warning and evacuation (‘soft’ measures) is important.
観測の目的Purpose of monitoring
観測の目的 Purpose of monitoring• 土砂移動現象の解明 ( 誘因→
発生→流下→堆積の過程 ) To make clear the soil movement phenomena (cause → occurrence → flow → sedimentation)
• 発生予測 ( 誘因、前兆現象から ) Prediction of occurrence (from the cause and warning signs)
• 発生の検知 Detection of occurrence
• 危険範囲の予測、対策計画 Prediction of hazard area and mitigation planning
• 予測・警戒避難の精度向上 Improvement of accuracy of prediction, warning and evacuation
• 警戒避難 Warning and evacuation