Journal of Applied Geology
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Seawater Intrusion Assessment based on Geological, Hydrogeological, Cl/Br vs Cl Graphical Analysis, Recharge Area, and Groundwater Usage in Makassar Coastal Area, South Sulawesi, Indonesia
Get PDFSeawater intrusion is a major concern in coastal urban areas like Makassar, where groundwater is a crucial water source. This study assesses seawater intrusion using multiple approaches, including geological and hydrogeological analysis, Cl/Br vs. Cl graphical analysis, recharge area land use, groundwater usage, and previous seawater intrusion vulnerability mapping. From 20 groundwater samples, five were categorized as brackish and then analyzed using these six perspectives. Geologically, two shallow wells in Mariso and Manggala contain brackish water due to trapped marine sediments, supported hydrogeologically by local groundwater flow patterns indicating past shallow seawater traps, while wells in Tallo show no such indications. Cl/Br vs. Cl graphical analysis classifies the shallow well in Tallo as Seawater, one in Manggala as Brine Basin, and three others as landfill leachate, suggesting anthropogenic contamination. Most groundwater recharge areas are residential and built-up, limiting infiltration and contributing to seawater intrusion. Groundwater usage is highest in Tallo, moderately high in Mariso and Manggala, and moderate in Ujung Pandang. Vulnerability mapping places the Tallo well in a high-risk zone, the Mariso well in a low-risk zone, and the Manggala well in a non-vulnerable area. Across these perspectives, only one sample in the Tallo District is confirmed to experience seawater intrusion
Significance Of Differences From Sumatera, Kalimantan, and Sulawesi Coal Based On Cluster Analysis And Statistics
No full textIndonesia has a complex geological structure with coal potential dominated by 3 main islands, Sumatra (SMS), Kalimantan (KS), and Sulawesi (SLS). However, the characteristics of coal on these three islands are not explained further. Therefore, this research is intended to see the significant differences in coal on Sumatra, Kalimantan and Sulawesi in terms of their characteristics. The research methods carried out include literature study, field activities, laboratory analysis including proximate analysis (total moisture, moisture, volatile matter, fixed carbon), total sulfur, calories, specific gravity, HGI, ultimate analysis (C, H, N, O, S), and coal ash analysis, as well as data processing using cluster analysis and principle component analysis (PCA). Result, 55 coal samples were obtained on these three islands which were divided into 9 main clusters with 50% similarity. Kalimantan Island has coal with an increase in TiO2, Al2O3, Na2O oxides with carbon and nitrogen elements. Sumatra Island has coal with increased TM, M, MnO, CaO, MgO, Fe2O3, and SO3 and a slight influence of HGI, TS. Meanwhile, Sulawesi Island has coal with complex parameters and an increase in calorific value. It is interpreted that the differences in coal characteristics are influenced by the different geological settings of these three islands in the past until resen
Excavation Method of Rock Masses at the Matenggeng Dam, Indonesia
Get PDFThis paper presents the results of engineering geological investigations and determination of rock mass excavation methods in the main dam area of Matenggeng Dam. The study was carried out through engineering geological mapping, core drill evaluation and supported by laboratory test data. Classifications of rock masses were carried out based on the Geological Strength Index (GSI) and Rock Mass Rating (RMR) to analyze the excavation method. The results showed research area consisted of lithology in the form of andesite, intercalation sandstone - gravelly sandstone unit, intercalation sandstone - siltstone unit, and alluvium deposits. However, at the main dam area consists of lithology in the form of intercalation sandstone-siltstone unit and intercalation sandstone-gravelly sandstone unit. The rock masses at the main dam excavation line have a weathering degree from moderately to complately weathered. Intact rocks have Uniaxial Compressive Strength (UCS) values ranging from 1-50 Mpa and are a category of extremly weak to moderate rocks. The rock mass of intercalation sandstone-siltstone with very poor to poor quality (GSI (0 - 58), RMR (8 - 45)), and intercalation sandstone-gravelly sandstone with poor to fair quality (GSI (20 - 59), RMR (20 - 68)). The recommended rock excavation method based on the EXCASS System is diggir, easy ripper, and hard ripper
Unsupervised Machine Learning for Determining Exploration Areas of Valuable Elements and Potential Toxicology Elements: A Case Study of the Bowen Basin Coal, Australia
Get PDFGlobal coal production and demand have increased anually. In addition to its potential as an alternative source of critical elements, coal also has environmental risks through toxicology elements. Australia is the world’s second-largest producer of rare earth elements (REEs) and critical elements, making coal exploration a key focus of the country’s mining strategy. An unsupervised Machine learning algorithm was applied to 56 coal samples from three pits in Bowen Basin, e.g., Blake Central Pit, Blake West Pit, and Bowen No. 2 Pit, to correlate trace elements with the geochemical characteristics of coal, such as proximate and major oxides. Blake West Pit is enriched in Ba, Br, and Sr, which associated with inherent moisture and phosphor (P), extending SE-trend. Blake Central Pit and Blake West Pit are enriched in Hf, Mo, Ta, Th, Y, and REY, which are associated with ash and major elements such as Si, Al, Ti, and K, with a trend of potential exploration towards N-NW. However, both pits show the risk of contamination from the toxic element Zn, which is associated with volatile matter, and major elements e.g., Fe, Mg, and Mn, with a trend of distribution towards S-SW. Based on the correlation analysis and regional geology, trace element enrichment in Bowen Basin is controlled by two main factors: 1) the transgressive phase during Early-Late Permian, which enriched inherent moisture, P, Ba, Br, and Sr, and 2) volcanic activity during Early Permian, which enriched silicate minerals and elements such as Hf, Ta, Th, W, and REY. Unsupervised machine learning has proven effective for preliminary coal characterization to support further exploration
Mineralogical and Geochemical Characteristics of Clays at Godean Hills, Yogyakarta – Indonesia (A Study Case at Gunung Patuk and Gunung Wungkal)
Get PDFGunung Patuk and Gunung Wungkal are part of the Godean Hills in Yogyakarta, Indonesia. The Godean Hills are isolated hills consisting of a series of hills surrounded by the Young Merapi Volcanics Deposits. A previous study reported that Gunung Patuk and Gunung Wungkal are porphyry andesite – micro diorite intrusions. Both hills are igneous rock intrusion and are found almost perfect soil profiles from the source/parent rock to the A horizon. However, another previous study suggests that at Gunung Wungkal has occurred hydrothermal alteration process. There is still a debate over the genesis of clay in that area, therefore this research needs to be carried out to provide a comprehensive understanding of mineralogical and geochemical characteristics of the clays at that area. The results of petrographic identification on the source/parent rock sample indicate that the rock sample is classified as andesite rock. Meanwhile, the results of mineralogy identification using the X-Ray Diffraction (XRD) method show that almost all types of soil profiles contain illite, kaolinite, and smectite. The calculation results of CIW (Chemical Index Weathering) and CIA (Chemical Index Alteration) values based on geochemical data show that CIW and CIA values increase steadily as they approach the ground surface. Based on the presence of illite (indicates a product relating to the relatively high temperatures) in horizon A with high values of CIW and CIA, therefore it can be interpreted that clay minerals at Gunung Patuk and Gunung Wungkal were the product of superimpose of hydrothermal alteration and weathering processes
Improving Landslide Susceptibility Using Groundwater Parameter in Samigaluh and Kalibawang Subdistricts
Get PDFLandslide susceptibility map is crucial in disaster risk management and it can be used for regional development plans. Landslide susceptibility map can be made by analyzing parameters that are assumed to affect landslides such as gradient slopes, geology, soil, and climate. Selection of landslide controlling parameters influences the accuracy of landslide susceptibility map. This study evaluates the effect of parameter that’s rarely used which is groundwater. The study area of this research was Kalibawang and Samigaluh Subdistricts, Kulonprogo, Special Region of Yogyakarta, Indonesia. Frequency ratio was used for the method along other parameters which is slope gradient, lithology, lineament density, land use, soil thickness. The result shows that groundwater parameter increase the accuracy by 22,29%. This study suggest that groundwater should be highly considered in landslide susceptibility mapping. In the other hand, groundwater depth mapping remains a challenge because most remote sensing method only detect shallow groundwater. Further research is necessary to develop better method for groundwater mapping using remote sensing or other indirect method
Engineering Geological Characteristics of Construction Area of Section 5 Yogyakarta-Bawen Toll Road, Magelang, Indonesia
No full textThis paper presents the results of engineering geological mapping conducted in Losari (Central Java), where the Section 5 of the Yogyakarta-Bawen toll road and tunnel will be constructed. This research aimed to evaluate the characteristics of the geomorphology, lithology, and geological structure for assessment of potential geological hazards during and after the toll road and tunnel constructions. This research was conducted by collecting geomorphological and geological data by surface mapping and surface rock engineering properties by laboratory testing, which were not done in the previous site investigation. The surface mapping results show that the study area is at the geomorphological units of steep and gentle slope volcanic hills. The study area consists dominantly of tuff and tuff breccia units. At the surface, the rocks are extremely weathered. The geological structures controlling the study area are extension joints with northwest-southeast and northeast-southwest orientation, consistent with the morphological alignment. Although the study area consists dominantly of hilly morphology and extremely weathered rocks, landslides are rarely observed. This may be attributed to the land use and relatively high friction angle of the soils resulted from weathering of pyroclastic rocks comprising this area. The soils may, however, be susceptible to remoulding. Therefore, cut slopes made for road and tunnel constructions are suggested to be designed to prevent change in the soil state
Monitoring and Early Warning of Slope Instabilities and Deformations by Sensor Fusion in Self-Organized Wireless ad-hoc Sensor Networks
No full textGeohazards, like landslides in soil and rocks which are induced by rainfall, flooding, earthquakes and human activity are dramatically increasing worldwide. Apart from socio-economic factors, like increasing population and concentrations of settlements on endangered areas, extreme weather conditions are the main reasons for this ascent. But, these occurrences are not only concentrated on the high mountain ranges with steep slopes and strong relief. In February 2003, a landslide in the middle of Germany near the village of Wolfstein-Rossbach damaged some houses (one of them totally). Another example is the Manshiet Nasser failure in Cairo in September 2008, where a large rock tilt buried many houses. This few examples show the devastating effect of geohazards in settlement areas and the need for precise monitoring systems to protect human life and property.
In the frame of the special program “Geotechnologien” of the German Federal Ministry of Education and Research (BMBF), the joint project “Sensorbased Landslide Early Warning System” (SLEWS) aims at the development of a prototypic Alarm- and Early Warning system (EWS) for different types of landslides using wireless sensor networks (WSN) for real-time monitoring. The WSN consists of a number of so called sensor nodes and a data collecting point (gateway). The solar powered gateway is connected either directly or by GSM/GPRS to the internet and subsequently to a data infrastructure to process the sensor data. Each node has a sensor board were the measuring sensors and the communication and processing unit are integrated. Special features of the Network are the real-time ability, self-organization and self-healing capacity, energy efficiency, bidirectional communication skills and data interfaces regarding OGC (Open Geospatial Consortium) specifications. The bidirectional structure of the system enables data transfer not only from each node to the spatial data infrastructure (SDI), but also to transmit commands or software-updates to individual or a group of nodes. Special sensor nodes for the monitoring of surface deformations due to landslides, measuring acceleration, tilting or extension, were developed and tested.
Apart from the detection of direct deformations caused for example by landslide movements, the system also allows the monitoring of indirect deformations on buildings and constructions, like bridge or retaining walls. Furthermore, the remote monitoring of flood control basins, dams or tailings in or close to housing areas becomes easy to set up in a cost-effective way. Open structures of the system enable a very rapid and flexible adjustment to the changed conditions and also permit a simple linkage with other data sources (e.g. climate data) or other sensor networks. Also, temporal deployments for safety purposes in road construction or foundation engineering become possible as the WSN is self-powered, the components are quite small and easy to set up. In the future other sensors may be integrated into the sensor notes so further tasks in spatial environmental monitoring may be covered.
Keywords: Slope instability, deformation, sensor fusion, sensor network
THE MECHANISM OF INITIATION AND MOTION OF THE RAPID AND LONG RUNOUT LANDSLIDES TRIGGERED BY THE 2008 WENCHUAN EARTHQUAKE
Get PDFThe 2008 Wenchuan earthquake triggered many rapid and long runout landslides, which made great loss of property and human lives directly. It is very important to understand the mechanism of initiation and motion of the rapid and long runout landslides. In this paper, field investigations on some typical landslides are introduced at first, and then the ring shear tests for simulating the initiation and motion of the Donghekou landslide are presented in details. The real seismic wave monitored in Shifang station was applied in the simulation test for the landslide initiation, while three different conditions of water content (dry, partially saturated, and fully saturated) were applied for the samples in the simulation tests to simulate landslide motion. It was found that the valley water and groundwater played a key role in the long runout and rapid landslide motion process during the great earthquake. This makes the difference for where landslide occurred but stopped soon and where landslides moved for long distance with high speed and killed many people. For the purpose of disaster mitigation, we strongly suggest that:(a) Avoid locating village in the landslide motion path, because the same event will occur in the future; (b) Avoid locating village and people on the landslide, because the landslide will deform easily with the seismic activity; (c) The attention should also be paid for landslide and debris flow during the reconstruction process for disaster mitigation in long period.
Keywords: Wenchuan Earthquake, rapid and long runout landslides, ring shear tests, initiation, motio
OBSERVATION AND SIMULATION OF TSUNAMIS INDUCED BY THE 2003 TOKACHI-OKI EARTHQUAKE (M 8.0)
Get PDFThe 2003 Tokachi-oki earthquake (MJ 8.0) occurred off the southeastern coast of Tokachi, Japan, and generated a large tsunami which arrived at Tokachi Harbor at 04:56 with a wave height of 4.3 m. Japan Marine Science and Technology Center (JAMSTEC) recovered records of water pressure and sea-bed acceleration at the bottom of the tsunami source region. These records are first introduced with some findings from Fourier analysis and band-pass filter analysis. Water pressure disturbance lasted for over 30 minutes and the duration was longer than those of accelerations. Predominant periods of the pressure looked like those excited by Rayleigh waves. Next, numerical simulation was conducted using the dynamic tsunami simulation technique able to represent generation and propagation of Rayleigh wave and tsunami, with a satisfactory result showing validity and usefulness of this technique.
Keywords: Earthquake, Rayleigh wave, tsunami, near-fiel