Page 107 - Navy Journal 219

Landslide in Hilly ...

Factors catalyzing landslide

Natural Factors: A Landslide occurs when part of a natural slope is unstable and
unable to support its own weight. If a slippery material is present below soil then
soil can become heavy with rainwater and prone to landside. It is a downward or
outward movement of soil, rock or vegetation due to gravitational force. This
movement can be fall, flow, side, spread or topple. Landslides occur usually at
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steep slopes but these may occur in areas with low slope gradient. These may
occur due to:
a. Weakness in the composition material or geological structure of rock or
soil formation.

b. External factors, which attest the ground water regimes such as heavy
rain, snowmen, change in ground water level etc.
c. Creation of new site conditions such as changes to natural slope due to
construction activities.

d. Earthquakes or volcanic activities.

Manmade Factors: The pressure of population and the economic exploitation of
the mountain region have been major causes for landslides. Huge
industrialization in hilly areas of coastal areas having cheapest labors, port and
shipping facilities offer investors to invest on industrialization. Turning forest
land into steel and glass processing plant are some of the activities that led to
increased chances of landslides. Factors such as deforestation by the timber
industry and shifting agriculture have also contributed to the removal of valuable
vegetation cover, leading to soil erosion and frequent landslides. Although,
Landslide is a natural disaster but it may occur due to manmade factors such as:
a. Construction work without proper survey of the site and without
designing and echo friendly engineering inputs.

b. Irrational farming technologies, for example, pouching in a lengthwise
direction down the slope, accelerate loss of substances on the slopes that
are eroded by weathering. These practices continue to deteriorate the
mountain slopes and make these slopes regions of landslides.

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