Landslides are simply defined as the mass movement of rock,
debris or earth down a slope and have come to include a broad range
of motions whereby falling, sliding and flowing under the influence
of gravity dislodges earth material. They often take place in conjunction
with earthquakes, floods and volcanoes. At times, prolonged rainfall
causing heavy block the flow or river for quite some time. The formation
of river blocks can cause havoc to the settlements downstream on
it's bursting.
In the hilly terrain of India including the Himalayas, landslides
have been a major and widely spread natural disaster the often strike
life and property and occupy a position of major concern
One of the worst tragedies took place at Malpa Uttarkhand (UP) on
11th and 17th August 1998 when nearly 380 people were killed when
massive landslides washed away the entire village. This included
60 pilgrims going to Lake Mansarovar in Tibet. Consequently various
land reform measures have been initiated as mitigation measures.
The two regions most vulnerable to landslides are the Himalayas and
the Western Ghats. The Himalayas mountain belt comprise of tectonically
unstable younger geological formations subjected to severe seismic
activity. The Western Ghats and nilgiris are geologically stable
but have uplifted plateau margins influenced by neo- tectonic activity.
Compared to Western Ghats region, the slides in the Himalayas region
are huge and massive and in most cases the overburden along with
the underlying litho logy is displaced during sliding particularly
due to the seismic factor.