A 3-tier tsunami vulnerability assessment technique for the north-west coast of Peninsular Malaysia     

H. Ismail  A. K. Abd Wahab  M. F. Mohd Amin  M. Z. Mohd Yunus  F. Jaffar Sidek  B. Esfandier J. 《Natural Hazards》2012,63(2):549-573

The 2004 tsunami that struck the Sumatra coast gave a warning sign to Malaysia that it is no longer regarded as safe from a future tsunami attack. Since the event, the Malaysian Government has formulated its plan of action by developing an integrated tsunami vulnerability assessment technique to determine the vulnerability levels of each sector along the 520-km-long coastline of the north-west coast of Peninsular Malaysia. The scope of assessment is focused on the vulnerability of the physical characteristics of the coastal area, and the vulnerability of the built environment in the area that includes building structures and infrastructures. The assessment was conducted in three distinct stages which stretched across from a macro-scale assessment to several local-scale and finally a micro-scale assessment. On a macro-scale assessment, Tsunami Impact Classification Maps were constructed based on the results of the tsunami propagation modelling of the various tsunami source scenarios. At this stage, highly impacted areas were selected for an assessment of the local hazards in the form of local flood maps based on the inundation modelling output. Tsunami heights and flood depths obtained from these maps were then used to produce the Tsunami Physical Vulnerability Index (PVI) maps. These maps recognize sectors within the selected areas that are highly vulnerable to a maximum tsunami run-up and flood event. The final stage is the development of the Structural Vulnerability Index (SVI) maps, which may qualitatively and quantitatively capture the physical and economic resources that are in the tsunami inundation zone during the worst-case scenario event. The results of the assessment in the form of GIS-based Tsunami-prone Vulnerability Index (PVI and SVI) maps are able to differentiate between the various levels of vulnerability, based on the tsunami height and inundation, the various levels of impact severity towards existing building structures, property and land use, and also indicate the resources and human settlements within the study area. Most importantly, the maps could help planners to establish a zoning scheme for potential coastline development based on its sensitivity to tsunami. As a result, some recommendations on evacuation routes and tsunami shelters in the potentially affected areas were also proposed to the Government as a tool for relief agencies to plan for safe evacuation.  相似文献   

Effect of soil hydraulic properties model on slope stability analysis based on strength reduction method   总被引：2，自引：0，他引：2  

Muhammad Mukhlisin  Marlin Ramadhan Baidillah  Aniza Ibrahim  Mohd. Raihan Taha 《Journal of the Geological Society of India》2014,83(5):586-594

Soil hydraulic properties models which have been proposed were derived based on the empirical fitting curve such as Brooks-Corey model (BC) and Van Genuchten model (VG), or based on soil pore radius distribution such as Lognormal model (LN). Each model has different accuracy for predicting soil moisture distribution. In the analysis of rainfall-induced slope failure, the soil hydraulic properties model was needed to describe the physical phenomena of behavior characteristic of water in unsaturated soil. As moisture content has an effect on soil strength, it is vital to select the suitable soil hydraulic properties model for predicting Factor of Safety (FOS) especially in forecasting landslide hazard. In this study, a numerical model of seepage finite element analysis using BC, VG, and LN model were used and compared in order to analyze the soil moisture distribution, water movement phenomenon, and slope stability characteristic in unsaturated soil slope based on the strength reduction method (SRM). The results showed that the variations of the parameters predicting the moisture content of soil leads to differences of FOS in some cases. The parametric study showed that for the unsaturated soil condition, BC model has the greatest FOS value than the other model, while VG model has the lowest. On the other hand, the FOS of all models have the same result for the saturated condition. Other than that, it was found that the increasing of ESP value in the surface layer has significant effect in the sub-surface layer.  相似文献   

REE mineralization in the carbonatites of the sung valley ultramafic-alkaline-carbonatite complex,Meghalaya, India   总被引：1，自引：0，他引：1  

Mohd. Sadiq  A. Ranjith  Ravi Kumar Umrao 《Central European Journal of Geosciences》2014,6(4):457-475

The Early Cretaceous Sung Valley Ultramafic-Alkaline-Carbonatite (SUAC) complex intruded the Proterozoic Shillong Group of rocks and located in the East Khasi Hills and West Jaintia Hills districts of Meghalaya. The SUAC complex is a bowl-shaped depression covering an area of about 26 km² and is comprised serpentinised peridotite forming the core of the complex with pyroxenite rim. Alkaline rocks are dominantly ijolite and nepheline syenite, occur as ring-shaped bodies as well as dykes. Carbonatites are, the youngest intrusive phase in the complex, where they form oval-shaped bodies, small dykes and veins. During the course of large scale mapping in parts of the Sung Valley complex, eleven carbonatite bodies were delineated. These isolated carbonatite bodies have a general NW-SE and E-W trend and vary from 20–125 m long and 10–40 m wide. Calcite carbonatite is the dominant variety and comprises minor dolomite and apatite and accessory olivine, magnetite, pyrochlore and phlogopite. The REE-bearing minerals identified in the Sung Valley carbonatites are bastnäsite-(Ce), ancylite-(Ce), belovite-(Ce), britholite-(Ce) and pyrochlore that are associated with calcite and apatite. The presence of REE carbonates and phosphates associated with REE-Nb bearing pyrochlore enhances the economic potential of the Sung Valley carbonatites. Trace-element geochemistry also reveals an enrichment of LREEs in the carbonatites and average ΣREE value of 0.102% in 26 bed rock samples. Channel samples shows average ΣREE values of 0.103 wt%. Moreover, few samples from carbonatite bodies has indicated relatively higher values for Sn, Hf, Ta and U. Since the present study focuses surface evaluation of REE, therefore, detailed subsurface exploration will be of immense help to determine the REE and other associated mineralization of the Sung Valley carbonatite prospect.  相似文献   

Predicting the geotechnical performance of Lisan Marl using finite element analysis,Dead Sea area     

Ziad Mansour  Zamri Chik  Mohd Raihan Taha 《Natural Hazards》2010,54(3):931-947

This paper investigates the changes in Lisan Marl properties upon leaching the soluble minerals and collapse potential. Finite element method was used to model dike construction and the relationships between soil parameters. To validate the chosen model and obtain the required input data, one dimensional oedometer and drained direct shear tests were carried out. The models were further validated by comparing the results with available published data. The results proved that the chosen model is efficient in assessing the geotechnical behavior of the studied soil.  相似文献   

Grain-size distribution and subsurface mapping at the Setiu wetlands,Setiu, Terengganu     

Rosnan Yaacob  Mohd Zaini Mustapa 《Environmental Earth Sciences》2010,60(5):975-984

A study was carried out around the lagoon and coastal area of Setiu wetlands to determine the general characteristics and grain-size distribution of their sediments. Sediment samples were collected from 39 stations of the lagoon area and 8 stations of the coastal area, and were analyzed for their sedimentological characteristics (mean, sorting, skewness and kurtosis). The sediment mean size ranged between 0.06–2.52 and 2.12–2.69 phi (Ø) for both lagoon and coastal sea-bottom sediments, respectively. Generally, the sediments in the study area consist mostly of coarse to fine particles. The major portions of the sediment are negatively skewed. This indicates that the study area is under the influence of the rather strong wave and current action. The study also encompassed the geophysical survey that was conducted near the coastal zone of the study area. The high-resolution seismic sub-bottom profiling technique is the standard method employed to map geological features and locate structures below the surface of the seafloor. Data obtained from seismic records were used to interpret the seismic reflectors. Three main reflectors (layers), which consist of the seabed and the seabed multiple, were traced using Sonar Web Pro software, and the results showed a uniform distribution pattern for all stations surveyed. It is envisaged that this method could be an effective way to image the marine subsurface structures; thus, its use is anticipated in the higher degrees of sedimentary research and marine resource exploration.  相似文献   

Land subsidence of Jakarta (Indonesia) and its relation with urban development     

Hasanuddin Z. Abidin  Heri Andreas  Irwan Gumilar  Yoichi Fukuda  Yusuf E. Pohan  T. Deguchi 《Natural Hazards》2011,59(3):1753-1771

Jakarta is the capital city of Indonesia with a population of about 9.6 million people, inhabiting an area of about 660 square-km. In the last three decades, urban development of Jakarta has grown very rapidly in the sectors of industry, trade, transportation, real estate, and many others. This exponentially increased urban development introduces several environmental problems. Land subsidence is one of them. The resulted land subsidence will also then affect the urban development plan and process. It has been reported for many years that several places in Jakarta are subsiding at different rates. The leveling surveys, GPS survey methods, and InSAR measurements have been used to study land subsidence in Jakarta, over the period of 1982–2010. In general, it was found that the land subsidence exhibits spatial and temporal variations, with the rates of about 1–15 cm/year. A few locations can have the subsidence rates up to about 20–28 cm/year. There are four different types of land subsidence that can be expected to occur in the Jakarta basin, namely: subsidence due to groundwater extraction, subsidence induced by the load of constructions (i.e., settlement of high compressibility soil), subsidence caused by natural consolidation of alluvial soil, and tectonic subsidence. It was found that the spatial and temporal variations of land subsidence depend on the corresponding variations of groundwater extraction, coupled with the characteristics of sedimentary layers and building loads above it. In general, there is strong relation between land subsidence and urban development activities in Jakarta.  相似文献   

Regional analysis of annual maximum rainfall using TL-moments method     

Ani Bin Shabri  Zalina Mohd Daud  Noratiqah Mohd Ariff 《Theoretical and Applied Climatology》2011,104(3-4):561-570

Information related to distributions of rainfall amounts are of great importance for designs of water-related structures. One of the concerns of hydrologists and engineers is the probability distribution for modeling of regional data. In this study, a novel approach to regional frequency analysis using L-moments is revisited. Subsequently, an alternative regional frequency analysis using the TL-moments method is employed. The results from both methods were then compared. The analysis was based on daily annual maximum rainfall data from 40 stations in Selangor Malaysia. TL-moments for the generalized extreme value (GEV) and generalized logistic (GLO) distributions were derived and used to develop the regional frequency analysis procedure. TL-moment ratio diagram and Z-test were employed in determining the best-fit distribution. Comparison between the two approaches showed that the L-moments and TL-moments produced equivalent results. GLO and GEV distributions were identified as the most suitable distributions for representing the statistical properties of extreme rainfall in Selangor. Monte Carlo simulation was used for performance evaluation, and it showed that the method of TL-moments was more efficient for lower quantile estimation compared with the L-moments.  相似文献   

Adsorption of Pb(II) Ions from Aqueous Solutions by Date Bead Carbon Activated with ZnCl2     

Mohammed Danish  Rokiah Hashim  Mohd Rafatullah  Othman Sulaiman  Anees Ahmad  Govind 《洁净——土壤、空气、水》2011,39(4):392-399

This study reports on the adsorption characteristics of Pb(II) ions from aqueous solutions using ZnCl₂‐activated date (Phoenix dactylifera) bead (ADB) carbon with respect to change in adsorbent dosage, initial pH, contact time, initial concentration, and temperature of the solution. Kinetic studies of the data showed that the adsorption follows the pseudo‐second‐order kinetic model. Thermodynamic parameters, enthalpy change (ΔH° = 55.11 kJ/mol), entropy change (ΔS° = ? 0.193 kJ/mol/K), and Gibbs free energy change (ΔG°) were also calculated for the uptake of Pb(II) ions. These parameters show that adsorption on the surface of ADB was feasible, spontaneous in nature, and endothermic between temperatures of 298.2 and 318.2 K. The equilibrium data better fitted the Langmuir and Freundlich isotherm models than the D–R adsorption isotherm model for studying the adsorption behavior of Pb(II) onto the ADB carbon. It could be observed that the maximum adsorption capacity of ADB was 76.92 mg/g at 318.2 K and pH 6.5.  相似文献   

An effective visualization and comparison of online terrain draped with multi-sensor satellite images     

Ruzinoor Che Mat  Abdul Rashid Mohamed Shariff  Biswajeet Pradhan  Ahmad Rodzi Mahmud  Mohd Shafry Mohd Rahim 《Arabian Journal of Geosciences》2013,6(12):4881-4889

The objective of this paper is to discuss the effectiveness of visualizing online 3D terrain draped with different satellite imageries. The topographic data of the study area were obtained from the contour maps of Universiti Putra Malaysia, Selangor, Malaysia. The high resolution satellite imageries used in this project involving QUICKBIRD (0.6 m resolution), IKONOS (1 m resolution), and SPOT5 (5 m resolution). R2V software was used for editing the contour data, whereas Arc GIS was used for overlaying the imageries over the 3D terrain data. Then the data were exported into Virtual Reality Markup Language to compare the effectiveness of different satellite imageries based on the data file size, imageries size, number of images tile, loading time during office hours (from 8 a.m. to 5 p.m.) and out of office hours (after 5 p.m.), frame rate per second, and visualization quality. The results revealed that IKONOS satellite imageries are better for an effective online 3D terrain visualization utilizing GIS data even though it has lower resolution compared to QUICKBIRD.  相似文献   

Opposition-based firefly algorithm for earth slope stability evaluation   总被引：2，自引：1，他引：1  

Mohammad KHAJEHZADEH  ;Mohd Raihan TAHA  ;Mahdiyeh ESLAMI 《中国海洋工程》2014,28(5):713-724

This paper introduces a new approach of firefly algorithm based on opposition-based learning （OBFA） to enhance the global search ability of the original algorithm. The new algorithm employs opposition based learning concept to generate initial population and also updating agents’ positions. The proposed OBFA is applied for minimization of the factor of safety and search for critical failure surface in slope stability analysis. The numerical experiments demonstrate the effectiveness and robustness of the new algorithm.  相似文献