Geoscience Reference
In-Depth Information
Chapter 1
Introduction
1.1 Key Concepts on Landslide
Landslides are simply de
ned as the movement of mass of dislodged rock, debris or
earth materials down a slope including a broad range of motions whereby falling,
sliding and flowing under the influence of gravity. A landslide is a type of
'
mass
wasting
or down slope movement of soil and/or rock under the influence of gravity
(USGS). The word
'
is actually a general term for several kinds of slope
movements and they can be classi
'
landslide
'
ed by
rate of movement, type of materials and nature of movement and presence of
lubricating agent (slide, slump, flow or fall, Chorley et al.
1985
). In Australia,
landslide is de
ed in several ways. They can be classi
ned as the movement of rock, debris or earth down slope. They
result from the failure of the materials which make up the hill slope and are driven
by the force of gravity. Landslides are known also as landslips, slumps or slope
failure. The most common types of landslide in Australia are earth slides, rock falls
and debris flows. The movement of landslide materials can vary from abrupt col-
lapses to slow gradual slides and at rates which range from almost undetectable to
extremely rapid. Sudden and rapid events are the most dangerous because of a lack
of warning and the speed at which material can travel down the slope as well as the
force of its resulting impact. Extremely slow landslides might move only milli-
metres or centimetres a year and can be active over many years (creep).
Landslide can also be termed as
. According to Chorley et al.
(
1985
)
'
Mass movement
'
is the detachment and down slope movement of soil and
rock materials under the influence of gravity. The sliding or flowing of the materials
are caused due to their position and to gravitational forces. But this type of movement
is accelerated by the presence of water, ice and air. Basically, all kind of rock-waste
movements including soil and ice are collectively termed as landslide. The moving
distance covered by the earth materials involved in landsliding from the place of
origin to the place of destination, called as
'
mass movement
'
'
run-out distance
'
.Tode
ne landslides,
we must de
ne fall, slide, flow, lateral spreads and topple as all these are the major
Search WWH ::
Custom Search