120
K. Shrestha et al.
Fig. 7.6 Distribution of
landslide with different
aspects
responsible for the landslide. In this river corridor, landslide was observed maximum
in the planar curvature.
Geology plays an important role in causing landslide failure. Most of the landslide
in the study area is found to contain Himal group and Ranimatta formation. Himal
group consists of rocks like marble, gneiss, magmatite, whereas Ranimatta formation
consists of phyllite, quartzite, metasandstone, and conglomerate (Ojha 2009). Thin
beds of phyllite between quartzite beds is one of the causes of the landslide. Phyllite
has less friction angle and higher weathering rate which gets weathered during long
environmental exposure, due to which the landslides are active. Himal group consists
of gneiss which contains more amount of feldspar and weathering rate of feldspar is
higher which undergoes chemical weathering with water. Due to which land sliding
is common in gneiss (Gasim et al. 2015).
Rainfall plays an important role in landslide triggering effects. Rainfall triggered
landslides are reported every year in different countries. Annual monsoon rainfall
in Nepal ranges from as low as 160 mm in the northwestern region to as high as
5500 mm in some of the isolated areas of central Nepal (Chalise and Khanal 2001).
The rainfall of intensity 2800–2900 mm is observed to have more landslide and the
area of landslide was observed to be increasing with the increase in the intensity
of rainfall in the Chepe River corridor. The distribution of the daily precipitation
K. Shrestha et al.
Fig. 7.6 Distribution of
landslide with different
aspects
responsible for the landslide. In this river corridor, landslide was observed maximum
in the planar curvature.
Geology plays an important role in causing landslide failure. Most of the landslide
in the study area is found to contain Himal group and Ranimatta formation. Himal
group consists of rocks like marble, gneiss, magmatite, whereas Ranimatta formation
consists of phyllite, quartzite, metasandstone, and conglomerate (Ojha 2009). Thin
beds of phyllite between quartzite beds is one of the causes of the landslide. Phyllite
has less friction angle and higher weathering rate which gets weathered during long
environmental exposure, due to which the landslides are active. Himal group consists
of gneiss which contains more amount of feldspar and weathering rate of feldspar is
higher which undergoes chemical weathering with water. Due to which land sliding
is common in gneiss (Gasim et al. 2015).
Rainfall plays an important role in landslide triggering effects. Rainfall triggered
landslides are reported every year in different countries. Annual monsoon rainfall
in Nepal ranges from as low as 160 mm in the northwestern region to as high as
5500 mm in some of the isolated areas of central Nepal (Chalise and Khanal 2001).
The rainfall of intensity 2800–2900 mm is observed to have more landslide and the
area of landslide was observed to be increasing with the increase in the intensity
of rainfall in the Chepe River corridor. The distribution of the daily precipitation