Landslides are a natural hazard that can endanger human life and cause severe environmental damage. A landslide susceptibility map is essential for planning, managing, and preventing landslides occurrences to minimize losses. A variety of techniques are employed to map landslide susceptibility; however, their capability differs depending on the studies. The aim of the research is to produce a landslide susceptibility map for the Langat River Basin in Selangor, Malaysia, using an Artificial Neural Network (ANN). A landslide inventory map contained a total of 140 landslide locations which were randomly separated into training and testing with ratio 70:30. Nine landslide conditioning factors were selected as model input, including: elevation, slope, aspect, curvature, Topographic Wetness Index (TWI), distance to road, distance to river, lithology, and rainfall. The area under the curve (AUC) and several statistical measures of analyses (sensitivity, specificity, accuracy, positive predictive value, and negative predictive value) were used to validate the landslide predictive model. The ANN predictive model was considered and achieved very good results on validation assessment, with an AUC value of 0.940 for both training and testing datasets. This study found rainfall to be the most crucial factor affecting landslide occurrence in the Langat River Basin, with a 0.248 weight index, followed by distance to road (0.200) and elevation (0.136). The results showed that the most susceptible area is located in the north-east of the Langat River Basin. This map might be useful for development planning and management to prevent landslide occurrences in Langat River Basin.
Landslides represent one of the world’s most dangerous and widespread risks, annually causing thousands of deaths and billions of dollars worth of damage. Building on and around hilly areas in many regions has increased, and it poses a severe threat to the physical infrastructure and people living within such zones. Quantitative assessment of social vulnerability in Malaysia is worrying because it has been given less attention than hazard-related studies. Therefore, this study’s objective is to find out the indicators used for social vulnerability assessment in the context of a landslide in Malaysia. The analysis is critical for understanding the measures of social vulnerability, given that the incorporation of climate change and disaster risk mitigation issues in urban planning and management are considered priorities in ensuring a stable population growth and avoiding economic disruption. A systematic study on the Scopus and Web of Science repositories was conducted based on the PRISMA Report analysis method. This article concluded that there are six important indicators of social vulnerability in the context of landslide in Malaysia.
Finding alternatives to natural resources is important for a sustainable future and is essential to infrastructure projects. Among these replacements is the use of coffee waste as soil stabilizers. Coffee husk ash (CHA) is a solid waste obtained by the processing of coffee beans on a farm or factory. The main aim of this study is to determine the geotechnical properties of clay soil treated with CHA to develop a low-cost, environmentally friendly alternative composition. Laboratory tests were conducted to investigate the influence of CHA on the physical properties and the mechanical properties of clay. The CHA concentration was adjusted from 5% to 25% by the dry weight of clay in 5% increments. The clay classification of the mixture becomes coarser following the addition of the CHA. At 25% CHA, a peak UCS of 130.83 kN/m2 was measured compared with the untreated clay of 89.17 kN/m2. In addition, the cohesion values and internal friction angles of soil for 0% and 25% CHA increased from 80.1 kN/m2 to 148.7 kN/m2 and from 16.1° to 25.8°, respectively. It was found that CHA can improve the strength of clay by forming a pozzolanic and hydration process that fills soil voids and binds particles together.
Monsoon floods that annually hit the east coast of Malaysia have brought a variety of implications, especially for those who inhabit the most vulnerable areas. This study aims to find the relationship between the socioeconomy of the community living and flood events in the district of Pekan, Pahang. This involved geographic analyses which combined data on vulnerability index components represented by Geographical Information System (GIS) mapping. A field survey was conducted to assess the Livelihood Vulnerability Index (LVI), comprising major and sub-components of vulnerability for ten sub-districts in Pekan. LVI mapping was performed for every major component of the LVI with spatial data on the district. Households in the Gancung sub-district were found to be more vulnerable to flooding impact, with a high exposure index (0.59), but reported a positive vulnerability based on adaptive capacity (0.06). Penyur (0.51) was the most vulnerable and sensitive in terms of food security during the flood season. LVI assessment in the Pekan district could be used as an indicator to change livelihoods, survival food storage practices, and other preventive measures in order to curb damages and injuries when annual flooding strikes in the future.
This study was conducted to evaluate the strength and volume change characteristics of a sedimentary residual soil mixed with bentonite (S1) when treated with three different enzymes. In addition, three reference clays including bentonite, illite, and kaolinite were also treated with enzymes to study the effect on their strength characteristics. Soil samples prepared at the optimum moisture content (OMC) were sealed and cured for four months. After curing, reference clays were tested for unconfined compressive strength (UCS). For swell tests, the S1 soil samples were placed on porous stones, which were immersed in water to allow capillary soaking of the samples. S1 samples were allowed to dry at ambient temperature for shrinkage test until the rate of reduction in volume became negligible. On completion of swell tests, the samples were tested for UCS to determine the decrease in strength due to saturation. No increase in strength and decrease in volume change were observed for any of the enzymes and dosages. Field Emission Scanning Electron Microscope (FESEM) showed some dense packing of particles for treated samples, whereas X-ray diffraction (XRD) did not reveal any change; in fact, the pattern for untreated and treated soil samples were indistinguishable.
31 January 2018 in Jàmbá: Journal of Disaster Risk Studies
Shelter centres are important locations to safeguard people from helpless situations and are an integral part of disaster risk reduction (DRR), particularly for flood DRR. The establishment of shelter centres, and their design based on scientific assessment, is crucial. Yet, they are very much related to the geographic location, socio-economic conditions and the livelihoods of the affected communities. However, many parts of the developing world are still lagging behind in ensuring such scientific design. Considering the flood disaster in 2014 that affected the residents living along the Pahang River Basin, in this study we delineate the communities at risk and evaluate the existing shelter centres to determine how they reduce people's vulnerability to the risks associated with rural and urban landscapes. We used spatial analysis tools to delineate risk zones and to evaluate existing evacuation systems. A flood disaster risk map was produced to determine which communities are living with risks. Subsequently, the distribution of shelter centres examined whether they are able to support people living at the flood risk zones. These centres were also evaluated using a set of international guidelines for effective disaster shelters. This reveals that the number of shelter centres is not adequate. The designation and designing of shelter centres are not being done scientifically. The maps produced here have a lot of potential to support disaster management decisions, in particular site selection and the prioritisation of centres. The study concludes with a set of guidelines and recommendations for structural and non-structural measures, such as alternative livelihoods and the potential of ecotourism, which may improve the resilience among flood-affected communities; and the decision-making process for the overall flood DRR initiatives.