Landslide hazard vulnerability (LHV): Review of literature and a proposed new approach in landslide risk management for Malaysia

Abstract

Topic on landslide hazard vulnerability (LHV) in Malaysia is relatively new and received little attention from geoscientists and engineers. Vulnerability is defined as the potential degree of loss (damage) to a given element or risk elements resulting from the occurrence of a natural phenomenon of a given magnitude. Although there are some guidelines and policies regarding hillside development to prevent landslide, the number of disastrous landslide events is steadily increases nationwide. This paper reviews and formulates the concept of LHV by taking into account the socio-economic and science aspects. New approach in vulnerability concept in landslide risk management (LRM) in Malaysia is also introduced. To achieve this goal, a framework was designed for assessing the LHV. The framework was formulated semi-quantitatively through the development of a database for the risk elements (human & properties) based on secondary data, review of literature and field observations. The vulnerability parameters include in assessing LHV are 1) physical implication (building structures, internal materials, property damage, infrastructural facilities and stabilization actions), social status (injury, fatalities, safety, loss of accommodation and public awareness) and interference on the environment (affected period, daily operation & diversity). Each parameters in the vulnerability assessment is allocated with a certain index value ranges from 0 (0 % damage/victims/period), 0.25 (1-25 % damage/victims/period), 0.50 (26-50 % damage/ victims/period), 0.75 (51-75 % damage/victims/period) and 1.00 (75-100 % damage/victims/period). All the data products from LHV observation were reanalysed based on standardization method to evaluate their significance in developing an acceptable and practical model for landslide risk management (LRM) that will suit best to the local conditions. The next step is to establish the index value for each ideal vulnerability parameters. Finally, the total average of index value for the three types of physical, human and environment vulnerabilities is classified into five classes of vulnerabilities, namely class 1 (< 0.20) (very low vulnerability), class 2 (0.21-0.40) (low vulnerability), class 3 (0.41-0.60) (medium vulnerability), class 4 (0.61-0.80) (high vulnerability) and class 5 (> 0.81) (very high vulnerability). Results from this study indicate that the index value for the vulnerability on landslide hazard in Malaysia is generally higher than those of the developed countries. This is mainly due to poor awareness, knowledge and exposure amongst the public, as well as poor building codes and lack of consideration on the hazard triggering factors (intense rainfall and earthquake). It is also noted that the index value of vulnerability cannot be simply determined quantitatively because it requires data from field observations supported by the relative secondary data.