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The Inner Terai Valleys of Nepal comprise several elongated river valleys in the southern lowland part of the country. These tropical valleys are enclosed by the Himalayan foothills, viz the Mahabharat Range and the Sivalik Hills located farther south.〔Nagendra, H. (2002). Tenure and forest conditions: community forestry in the Nepal Terai. Environmental Conservation 29 (04): 530–539.〕 The Inner Terai is called "bhitri tarai भित्री तराइ" in Nepali.〔Gurung, H. (1971). Landscape pattern of Nepal. Himalayan Review 4: 1–10.〕 The Inner Terai Valleys are part of the Terai-Duar savanna and grasslands ecoregion.〔Dinerstein, E., Loucks, C. (2001). 〕 They are filled up with coarse to fine alluvial sediments.〔Hasegawa, S., Dahal, R. K., Yamanaka, M., Bhandary, N. P., Yatabe, R., & Inagaki, H. (2009). Causes of large-scale landslides in the Lesser Himalaya of central Nepal. Environmental Geology 57 (6): 1423–1434.〕 Malaria was prevalent until the late 1950s. Since its eradication, the area became a viable destination for large-scale migration of people from the hills, who transformed the area from virgin forest and grassland to farmland.〔Gurung, H. (1988). Nepal: Consequences of migration and policy implications. Contributions to Nepalese Studies 15 (1): 67–94.〕 The Chitwan Valley and the Dang and Deukhuri Valleys are some of the largest Inner Terai Valleys. ==Geology== (詳細はHimalayas were formed by the collision of the Indian sub-continent with Eurasia, which began about 50 million years ago and continues today. The oceanic crust in front of India slid under Eurasia, pushing up the Tibetan plateau. The Indian continental crust is also pushing under Tibet, but is partly compressed and thrust upward to form the Himalayan mountain range, extending for over 2400 km and rising as high as 8848 m at Mt. Everest Chomolangma. The Himalayas have four tectonic subdivisions: * The Indus Suture Zone, where the Indian Plate meets the Eurasian Transhimalaya or Karakoram-Lhasa Block. * The Central Himalayan Domain, the high backbone of the Himalayas bounded on the south by a fault zone called the MCT (Main Central Thrust) that has elevated these peaks three or four thousand meters above lower ranges to the south. * The "middle hills" below the MCT south to the Lesser Himalaya or Mahabharat Range which is bounded by another fault zone, the MBT (Main Boundary Thrust) that abruptly elevates the Mahabharats 1,000 to 2,000 meters above hills further south. * The Sub-himalaya also known as the Muree, Chure Hills or Siwaliks, which are the southernmost foothills of the Himalayan Range and mainly composed of folded and overlapping sheets of sediment from the erosion of the Himalaya. They are bounded on the south by the HFT (Himalayan Frontal Thrust) elevating them about 500 meters above the Gangetic plain. The Inner Terai valleys lie between the Siwalik and Mahabharat ranges or sometimes between different ranges in the Siwaliks. They hold flat plains with winding rivers that shift course from time to time, running northwest or southeast along the axis of the Siwalik ranges until they find a break and flow into the Outer Terai and Gangetic plain. Usually there is little difference in elevation between the Inner Terai valley floors and the plains of the Outer Terai. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Inner Terai Valleys of Nepal」の詳細全文を読む スポンサード リンク
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