INGENIEUR
Relevant element-at-risk characteristics
(for example types, materials, dimensions and
locations) are essential for detailed classification
of each element-at-risk. Each element-at-risk is
classified into its sub-classification scheme based
on its main characteristics. This information is
combined with the landslide hazard index as
a primary input for expert-based vulnerability
assessments.
METHODOLOGY
Figure 2.1 shows the overall methodology which is
divided into eleven stages as follows:
The overall method of assessing and
developing the parameters/indicators of landslide
vulnerability assessment and risk index of
critical infrastructures can be divided into four
main stages namely 1) data acquisition and pre-
processing of geospatial data; 2) improvements
in landslide vulnerability clusters, indicators,
sub-indicators and weight values; 3) landslide
vulnerability and risk mapping in Cameron
Highlands and; 4) evaluation of the landslide
vulnerability and risk assessment methodology.
The first stage focused on the data acquisition
that included geospatial and non-geospatial
data. The geospatial data included acquisition
of high-resolution aerial photos at Ringlet and
Lembah Bertam, Cameron Highlands. The aerial
photos were processed to produce digital terrain
models (DTMs), digital surface models (DSMs)
and orthophotos of the study areas. In addition,
several other ancillary data were obtained from
different agencies, for example: landslide hazard
maps, high resolution DTMs and orthophotos from
the Mineral and Geoscience Department (JMG).
Finally, the input information for the proposed
landslide vulnerability and risk assessment such
as initial information on the clusters (C, E, I, and
P), indicators, sub-indicators and weights were
obtained via intensive literature reviews.
The second stage focused on improvements
of landslide vulnerability clusters, indicators,
sub-indicators and weight values. Several focus
group discussions (FGDs) were conducted with
stakeholders and internal experts to improve
the landslide vulnerability and risk assessment
methods. The first FGD was conducted with
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different stakeholders. The FGD involved
detailed explanation on the concept of landslide
vulnerability and risk assessment which included
step-by-step explanation on the procedure used
in determining the clusters, indicators, sub-
indicators and weight values. Each participant
was required to fill in a specially designed
survey form for landslide vulnerability and risk
assessments. The outcomes from this FGD
were further improved with specific FGDs with a
group for a dam and TNB powerlines. Finally, all
the input for the landslide vulnerability and risk
assessment of each CI and landslide type was
evaluated and finalised by the internal experts
of the consultant group. Several analyses were
carried out to determine the consistency of inputs
from stakeholders, the sensitivity of each indicator
and cluster, and the reliability of the vulnerability
index based on simulation of different landslide
vulnerability scenarios (worst, medium and best
case scenarios). The consistency analysis was
aimed at analysing the consistency of weight
values assigned by the stakeholders for the
indicators and sub-indicators through the analysis
of the standard deviation of weight values between
participants. The sensitivity analysis focused on
analysing the sensitivity of each indicator and sub-
indicator towards the estimation of the landslide
vulnerability value (index) based on the one-at-a-
time (OAT) method. The simulations on the other
hand analysed the reliability of weight values
given by the stakeholders and internal experts
(for each CI and landslide type). The best case
landslide scenario was expected to produce the
lowest vulnerability value that can be classified
as a “very low vulnerability” class. The medium
case landslide scenario was expected to produce
a medium vulnerability value that can be classified
as a “moderate vulnerability” class. Finally, the
worst case landslide scenario was expected to
produce the highest vulnerability value that can
be classified as a “very high vulnerability” class.
The landslide vulnerability and risks were grouped
into five classes namely, very high, high, moderate,
low and very low landslide risk areas.
The landslide vulnerability map was classified
using the same five classes. The landslide
risk map was produced based on the matrix
combination of landslide vulnerability and hazard
classes. The landslide hazard map of the study