Introduction - Semi-quantitative Approaches for Landslide Assessment and Prediction - page 3

1.2 A Brief Account of Some Destructive
Landslides Occurrences

The large scale landslides in populated areas made a disastrous effect on natural
environment and human structure. The scale of damage caused by earth-quake
triggered landslide is more destructive than any other type of causative factors. The
destructive slope movements may threaten single structure, villages or towns;
agricultural and forest land; communication lines and tunnel in use or under con-
struction; reservoirs and lakes. In 1584, a large scale landslide on the Rhone valley
side slopes wrecked the community of Yvorne and more than 300 lives were lost
(Heim 1932 ). A catastrophic slope failure (rock slide) took place in North America
which destroyed part of the town of Frank in Canada in 1903 and only within 2 min
about 30 million m 3 of Carboniferous limestone wiped out from the mountain face
and buried long railway track and took 70 lives (McConnel and Brock 1904 ). The
disastrous landslide occurred near Vaerdalen, north of Trondheim in Norway in
1893 (Holmsen 1954 ) and that destroyed 22 farms and 11 persons were killed. In
1920, the Kansu Province of China got affected by great magnitude earthquake and
caused the sliding of thick loess deposits covering an area of 160 480 km and

killed about 200,000 people (Close and McCormick 1922 ). In 1935 a noteworthy
tunnel failure took place due to landslide in New Zealand (Benson 1940 ). In 1936 a
rock fall, 10 6 m 3 in volume occurred near Loen and produced a 74 m swell in the
Nordfjord that resulted a loss of 73 lives (Bjerrum and Jorstad 1966 ). Sometimes
major landslides are indirectly responsible for catastrophic events that occur when
the slipped material blocks a river and hold back the water. One of the biggest
catastrophy of this kind occurred in the Southern Alps in the Sixteenth Century.
Extensive landslides of this kind were recorded in the Himalayan region and in this
way in 1893 a temporary 320 m high dam was created on the upper Ganges. One of
the largest slope failure of this type occurred on April 25, 1974 in the Mantaro river
valley in Peru. Kojan and Hutschinson ( 1978 ) treated the high rate of river erosion
as a signi

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cant contributing factor of landslip which resulted in a very deep valley
with steep slopes. Recently (2013), the Himalayan region faced destructive slope
failure events and that have taken unexpected causalities. Statistical records prove
that landslide is one of the most destructive natural hazards all over the World
(Tables 1.1 and 1.2 ).

1.3 Relevance of the Landslide Study

In the hilly terrains of India, landslides have been a major and widely spread natural
disaster that often strike life and property and occupy a position of major concern.
In India, two regions are most vulnerable to landslides i.e. the Himalayas and the
Western Ghats (Fig. 1.2 ). The Western Ghats and Nilgiris are geologically stable