Describe major geological hazards in Higher Himalaya Zone. [2068 Bhadra] [3]

The higher Himalaya of Nepal is exposed dominantly to rock falls, rock slides etc. as this zone is composed of hard crystalline metamorphic rocks with adverse orientation as well as many glacial lakes in threat of breaching. In many places landslides have dammed the deeply incised rivers contributing to landslides dammed outburst flood (LBOF), which is for example very common in kaligandaki valley. A glacial lake outburst flood (GLOF) is a catastropic surge of water and debris caused by sudden outburst of glacial lakes. It creates serious problem for cultivated land, infrastructures etc. Glacial lakes in Nepal Himalaya are classified as: Moraine dammed lakes, Glacier ice-dammed lakes, and ice core-moraine-dammed lakes. The transportation of sediments during a GLOF is exceptionally great and materials is eroded from riverbanks, terraces, and slopes. As a result, several slope instabilities are triggered. (note: for the design of hydropower project, road in this zone vicinity of snow ....

The higher Himalaya of Nepal is exposed dominantly to rock falls, rock slides etc. as this zone is composed of hard crystalline metamorphic rocks with adverse orientation as well as many glacial lakes in threat of breaching. In many places landslides have dammed the deeply incised rivers contributing to landslides dammed outburst flood (LBOF), which is for example very common in kaligandaki valley. A glacial lake outburst flood (GLOF) is a catastropic surge of water and debris caused by sudden outburst of glacial lakes. It creates serious problem for cultivated land, infrastructures etc. Glacial lakes in Nepal Himalaya are classified as: Moraine dammed lakes, Glacier ice-dammed lakes, and ice core-moraine-dammed lakes. The transportation of sediments during a GLOF is exceptionally great and materials is eroded from riverbanks, terraces, and slopes. As a result, several slope instabilities are triggered. (note: for the design of hydropower project, road in this zone vicinity of snow fed rivers, a civil engineers must consider these factors during site selection, investigation and design.) Some geological problems of this region are:

• Landslides,
• Debris flow,
• Slope failure,
• Earthquake,
• GLOF,
• snow avalanches,
• rock falls.