Malaysian Journal of Geosciences (MJG)

Evaluation of textural parameters were carried out to understand the arrangements of reservoir matrix (rocks). Well data were obtained from wells 001, 002 and 003 and used to generate suites of logs like gamma ray, density and sonic. Microsoft Excel was the software adequately used. The lithology was identified as sand for gamma ray information less than 75 API (or shale if this value is greater than 75 API). Gamma ray log and density log with respect to depth were generated. These results were used to obtain porosity; the average result of porosity estimated are approximately 17.42%, 29.98% and 17.53% from wells 001, 002 and 003 respectively. The outcomes of sorting, skewness and kurtosis are 9.09, 1.62 and 0.47 respectively for well 001; 1.52, 0.23 and 1.20 respectively for well 002 and lastly, corresponds to 4.76, 0.22 and 0.60 for well 003. The matrices making up the lithology are therefore extremely poorly sorted, very fine skewed and platykurtic for well 001; poorly sorted, coarse skewed indicating high energy environment and leptokurtic for well 002; poorly sorted, coarse skewed (high energy environment) and very platykurtic for well 003. Moreso, the porosity obtained is in the good class for wells 001 and 003 but excellent for well 002.

Dhaka the capital city of Bangladesh has experienced a steady loss of waterbodies over the last few decades due to unsustainable urbanization and climate change. This study employs remote sensing and geospatial technology to investigate the spatial-temporal changes of waterbodies of Dhaka city over a 30-year period. This study relied, primarily, on the Normalized Difference Water Index (NDWI) method for the identification and classification of the waterbodies (and non-waterbodies) followed by change detection and accuracy assessment. In addition to this NDWI approach, a supervised LULC classification -followed by change detection has been undertaken for the evaluation of the spatial and temporal dynamics of the LULC classes(Bare Land, Built-up Area, Vegetation and Waterbody). The results of the NDWI-based assessment primarily demonstrate that the extent of the waterbody area has disappeared significantly, from 84.19 km2 in 1992 to37.20 km2 in 2022. This indicates that more than half of the waterbody area has been lost over these 30 years. The overall classification accuracy was 88%, 92% and 90% respectively for the study years 1992, 2007 and2022, with kappa values of 0.84, 0.88 and 0.86 for each respective study year. The supervised LULC classification and change detection present a dynamic picture of the LULC transition, which reveals that the growth of built-up areas is the principal driver leading to the loss of 15.083 km² of waterbodies and 27.483km² of vegetation over the study period. Finally, based on the findings, this study provides a briefing on the likely reasons underlying this dynamic LULC transformation as well as plausible policy strategies to reverse the trend. The findings of this study could be useful to policymakers for the long-term planning and management of urban water resources as well as sustainable urban planning and environmental management of this capital city.

Malaysia is a rapidly developing country with expanding urban coastal populations, which in turn increases their vulnerability to tsunamis. This research sets out to establish the risk to Sabah’s coastline of a potential tsunami threat and identify the vulnerabilities of six large coastal communities in Sabah namely, Kota Kinabalu, Kudat, Sandakan, Lahad Datu, Semporna and Tawau, to such a tsunami. Using topographical data from digital elevation models, mangrove forest distribution data from Global Mangrove Watch, as well as OpenStreetMap data, the creation of GIS maps allowed the identification of topographical vulnerabilities of these communities as well as the identification of vulnerable infrastructure with the use of GoogleEarth. This data was supplemented by information obtained from interviews with three Malaysian professionals whom possess earthquake and tsunami knowledge and experience. Vulnerable features for each community were identified and scored to provide a comparative figure. The coastal settlement identified as exhibiting the greatest vulnerability overall is Sandakan, mainly due to a lack of significant protective natural barriers, extensive low coastal elevation zones, a very dense coastal population within 1km of the coast, extensive number and size of water villages and a single route of access to and from the city. The findings of this research provide a foundation for further exploration into Sabah’s coastal vulnerability to tsunamis and provides an initial focus for the Malaysian Government and other agencies involved in disaster risk reduction to direct their efforts in reducing the vulnerability of Sabah’s coastal communities to a potential tsunami.

The Kalimpong district of West Bengal stretches overlesser Himalaya which is highly susceptible to landslides along the SH-12. The research offers valuable insights into the relationship between natural hazards and human systems in this area and also investigates the affected institutions and communities to manage landslide.The present research attempts to explore the important factors responsible for slope instability and the critical examination of attributes underscores the complex interplay of geological, topographical, and environmental factors which mainly includes the steepness of the slope, low strength of rock, porosity and permeability of rocks and active soil erosion. Additionally, to investigate the community-based adaptation practices (CAP) to prevent landslide occurrences, Analytical Hierarchical Process (AHP) has been applied. For stakeholders and decision makers it emphasizes the critical need for comprehensive understanding and proactive mitigation strategies to mitigate their potentially devastating impacts on human settlements and infrastructure.

Assessment into the source of building failure was conducted within the Bauchi metropolis, northeastern Nigeria. Recently, the loss of lives and properties in the area was due to building failures. Geotechnical, geochemical, mineralogical, and geophysical methods of investigations were employed to test likely features responsible for this anomaly. Results from sieve analysis showed that the proportion amount of clay ranges from 1.0 – 70.0%, Optimum Moisture Content (OMC) ranges from 9.3 – 15.3%, Liquid Limit (LL) 25.8 – 43.2%, Plastic Limit (PL) 20.8 – 34.2%, Plasticity Index (PI) 4 – 14%, Maximum Dry Density (MDD) 1605 – 2005 kg/cm3, specific gravity (SP) range from 2.7 to 2.8%, permeability (k) 2×10¯5 to 21×10¯5 m/s. Triaxial test result also shows high cohesion values of 81.30105.00 kPa, and low angle of internal friction in the range of 11.750 – 20.460, with a low bearing capacity of 35-209 KNm2. Clay mineral predominates the studied soil as smectite shown by X-Ray Diffraction (XRD). Results from Vertical Electrical Sounding (VES) revealed a three-layered formation, comprise of Topsoil, with resistivity values ranging from 64.13 to 352 m, and a weathered layer (saprolite), with resistivity of 11.99 to 118 m and fresh Basement. Hence, a significant amount of smectite with high swelling and shrinkage potential, low permeability, and low resistivity among others as factors responsible for the basis of building failure experienced in the study area. These make the soils unsuitable for siting of a building. Thus, the need for stabilization and improvement before building construction.

Well log data acquired from three wells (BOK – 14, BOK – 16 and BOK – 19) from an onshore Niger Delta field (BOK) where used to carry out petrophysical analysis of the field to determine the prospectivity of the field. The Petrel software 2014TM was used for the petrophysical analysis and prospect identification. The petrophysical analysis revealed four hydrocarbon bearing reservoir sand formations with volume of shale ranging from 13.09% to 22.95%, effective porosity ranging from 19.24% to 24.23, 13% to 22.85%, net to gross ranging 38.66% to 75.40% and hydrocarbon saturation of 54.85% to 72.53%. From the petrophysical properties computed after the detailed petrophysical analysis from the well log data, it was evident that the identified reservoirs in BOK field had very good to excellent petrophysical properties ranges and were therefore prolific, holding great prospects for hydrocarbon fluid saturation which could be exploited for profitable use.

In recent decade (century), variation of streamflow and sediment load in different catchments has received considerable attention due to the complex pattern and trends of the river behavior. Detailed investigations were achieved on the changes of streamflow and sediment concentration through hydro-climatic conditions. Two fundamental questions about the utility of the sediment rating curve technique in the assessment of sediment load in relation to geomorphic conditions were discussed in the present paper: (i) how is the efficiency of the parameters, a and b, to characterize trends in the data?, and (ii) what are the possible relationships of the sediment rating parameters and the hydroclimatic events? For this reason, the present study attempts to examine the relationship of sediment transport and streamflow recorded at three gauging stations in the Seybouse basin in relation to their controls at the annual and monthly levels. The rating parameters obtained from the power functions of sediment discharge and water discharge data were investigated and associated with rainfall and runoff of the selected basins in order to characterize the trends of the parameters a and b at different river water and sediment supply conditions. The relationship between the constant a and the hydraulicity, during humid years, is solely high in the Bouhamdane. The association of a and rainfall includes mainly Mellah catchment. The seasonal models of the relationship between sediment yield and water discharge give for the fall and summer, in Bouhamdane catchment, the highest values of the constant a. This reflects the existence of data that are sometimes extreme which lead to a rise of the value of a, whereas the rate of the produced sediment yield is often low during these often dry seasons. It is outlined from the studied models that they cannot be used every in other basins. Also generalize them to any erosion proves to be a doubtful and inadequate operation.

A field-based geological mapping and geospatial approach were used to characterize the geological structures of the study area, intended at increasing the structural geological knowledge of the area. Geological mapping of Nigeria has been ongoing since 1964, with periodic updates that may overlook local geology due to the extensive area coverage. There is a need to promote local geologic mapping as a means of addressing this limitation. Four different rock types were identified; migmatitic gneiss, banded gneiss, mica schists and biotite granite as well as later igneous intrusive bodies. Results from petrographic analysis showcase a naverage mineralogical composition ranging from quartz (30%), orthoclase (23.27%), biotite (36.25%), and hornblende (5%) to other accessory minerals (5%). This research aimed at creating an updated structural geologic map of the study area, taking into account the sequence of deformational past of the area. Over 205structural geological features, including faults and joints, were meticulously measured using geological tools. The utilization of structural geological software, such as OpenstereoTM among others, facilitated statistical data visualization and evaluation. The results from rose diagrams and stereographic projections revealed a prevailing structural trend of NW-SE, N-S and NNE-SSW directions, with mean values of 310o±5, 010o±2, and034o±2 respectively. Consequently, the direction perpendicular to the aforementioned trend (i.e., NE-SW)aligns with the paleo stress field responsible for the area’s structural deformation.

This study evaluated the environmental effects of gold mining in the Opa River Basin of Southwestern Nigeria, employing multi-temporal Landsat imagery alongside Google Earth Engine. It also examined changes in land use and cover, as well as NDVI and NDWI from 1991 to 2024. Results reveal significant transformations in the landscape, including the growth of mining hotspots, deforestation, and a decline in vegetation health. Statistical analysis of NDVI indicates a reduction in vegetation vigor near mining areas, pointing to ecological disturbances. Furthermore, NDWI analysis establishes a connection between mining activities and increased water turbidity, reflecting higher levels of suspended sediments. This research underscores the essential role of open-access remote sensing data in developing countries with limited research budgets. By accurately identifying mining hotspots and quantifying environmental degradation, it demonstrates the effectiveness of Landsat data for remote monitoring. The findings stress the urgent necessity for comprehensive regulatory frameworks and sustainable management strategies to mitigate the detrimental effects of gold mining, ensuring the ecological integrity of the basin and the welfare of local communities. The reliance on publicly accessible satellite data provides a cost-efficient and replicable methodology, empowering researchers in resource-constrained settings.

Metamorphic rocks are useful in many heat-based geotechnical facilities since they are believed to be strong and durable due to their crystalline nature. However, rocks get degraded under repeated thermal stress. This work evaluates the effect of repeated heating and cooling on the geochemistry, mineralogy, microstructure and physical properties of some metamorphic rocks from the Nigerian Basement Complex. Effect of cooling condition was also investigated. Marble, granite gneiss and banded gneiss were subjected to fifty cycles of heating and cooling in air and water using heating temperature between 100 oC and 700 oC. Marble samples used in the study completely disintegrates at the 35th cycle of heating and air-cooling at 500 oC. They could not withstand more than 26 cycles of heating and air-cooling at higher temperature of 700 oC. The porosity, water absorption and degradation degree are highest in marble and least in granite gneiss. The crushing strength of both samples of granite gneiss is higher than that of banded gneiss and marble. Similar trend was observed in the residual values of these physical properties after fifty thermal cycles. Microstructural images showed micro-cracks in the thermally stressed rocks. However, no changes in mineralogy and geochemistry were recorded in the rocks. The water – cooled samples exhibited greater degradation than the air-cooled ones. Granite gneiss is more resilient than banded gneiss while both gneisses are more durable than marble. Metamorphic grade appears to play a major role in the resilience of the rocks to degradation.