Journal of Geoscience, Engineering, Environment, and Technology
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3D Natural State Modeling of Mount Iyang-Argopuro Geothermal Area, East Java, Indonesia
Full text linkMount Iyang-Argopuro is one of the geothermal working areas in the East Java. Mount Iyang-Argopuro has the potential of 185 MWe of reserves and 110 MWe of resources. It is estimated to have a liquid dominated reservoir with temperature up to 250-275 oC. An early 3D natural state numerical model of Mount Iyang-Argopuro Field is created using TOUGH2 simulator in order to identify the undisturbed condition of reservoir and resource assessment. Since Mount Iyang-Argopuro geothermal area is still in the exploration stage, the model created based on based on geological, geophysical, and geochemical data. The model has an area 14 km x 8.2 km and 9180 m in thickness. The model consists of 7410 of rectangular cell blocks with the roughest cell size is 1000 m x 1000 m and the finest is 200 m x 500 m. The model is verified by matching the model temperature and pressure profiles to the calculated geothermometer temperature and pressure, which shows good match enough
Total Organic Carbon (TOC) Value Prediction in Source Rock Potential at North East Java Basin, Indonesia
Full text linkThis research aims to determine the potential of the source rock in the Kujung and Cepu Formations in the North East Java Basin, using Total Organic Carbon (TOC). TOC is calculated using the Passey method. The Passey method is used by overlaying the sonic log and the resistivity log and determining the baseline to get the separation of Δlog resistivity, which is then used to predict the TOC log by including the LOM (Level of Organic Maturity) variable obtained from the data of vitrinite reflectance. After the TOC log value is obtained, a correlation is made with the TOC core value. The prediction result of TOC log in a PM-1 well is 2.16%, which means it has excellent quality. The prediction of TOC log in a PM-2 well is worth 2.68%, which means it has excellent quality. The correlation value between the TOC log and the TOC core of the PM-1 well is 0.67, which means the correlation is strong. In PM-2 well, the correlation between the TOC log and TOC core is 0.92, which means that the correlation is robust
Integrated Subsurface Analysis of Thickness and Density for Liquefaction Hazard: Case Study of South Cilacap Region, Indonesia.
No full textThe thickness of the liquefable layer can be the factor inducing liquefaction hazard, apart from seismicity. Several studies have been conducted to predict the possibility of the liquefable layer based on the filed sampling. However, a detailed investigation of the subsurface interpretation has not been defined, in particular the thickness estimation of the liquefable layer. This study is carried out in south Cilacap area where potential liquefaction is exists due to the earthquake history data and near surface condition. The aim of this study is to investigate the physical properties and thickness distribution using GGMplus gravity data and resistivity data. This research is conducted by spectrum analysis of gravity model and 2D resistivity model . This study’s main results is by performing the residual gravity anomaly with the associated SRTM/DEM data to define the subsurface physical distribution and structural orientation of the area. Residual gravity anomaly is also separated through the low pass filter in order to have robust interpretation. The residual anomaly indicates that the area has identical structural pattern with geological and SRTM map. The results show a pattern of high gravity index in the northeast area of the study having range of 70 – 115 MGal gravity index, associated with the volcanic breccia, and a low gravity profile with less than 65 in the southwest, associated with the alluvial and water table dominated distribution. The thickness of Alluvial is determined by resistivity model with H1 at a range of 3 meters and H2 at a range of 4 m. This research is included in the potential liquefaction category with the potential for a large earthquake
Carbon Dioxide (CO2) Emissions Due to Motor Vehicle Movements in Pekanbaru City, Indonesia
Full text linkLand use has a very close relationship with transportation. Transportation is formed as a result of the interaction between land use and its support system. Good land use supported by good infrastructure will result in good movement as well. Accessibility is one of the supporting factors for good interaction between transportation and land use—the better the land use conditions in an area, the greater the movement in that area. However, the interaction between land use and transportation can cause one of the problems: the increase in carbon dioxide emissions due to the more significant movement of motorized vehicles. Motor vehicles are the most significant contributor to carbon dioxide (CO2) emissions in the world. The further the route traveled by motorized vehicles, the more carbon dioxide (CO2) emissions will increase. This study aims to analyze the average total emission of carbon dioxide (CO2) resulting from transportation activities in Pekanbaru City into two parts, namely: (1) Based on Travel Time (2) Based on the type of vehicle. Vehicle Kilometers of Travel (VKT) and Emission Factors are the primary data in calculating Carbon Dioxide (CO2) Emissions. The research area consists of 12 zones involving 1,342 households in Pekanbaru City. Based on travel time, 52% of community motorized vehicle movement activities are carried out in the morning. Private cars contribute 65% of carbon dioxide (CO2) emissions in Pekanbaru City based on the type of vehicle. This study found that a high number of motorized vehicles cannot be used as a benchmark that the resulting emissions will also be high. However, the emission of carbon dioxide (CO2) depends on the fuel consumption of each vehicle. The higher the fuel consumption, the higher the amount of carbon dioxide (CO2) emissions released by motorized vehicles
Mapping of Sediment on the Waters Around Panjang Island, Banten Bay, Indonesia
Full text linkThis study was conducted to map the surface sediment conditions in the waters around Panjang Island, Banten Bay. The survey method was conducted in February 2015 by taking sediment samples using a grab sampler at 15 stations. Sediment analysis was conducted to determine the grain size using the granulometry method which was then processed using the KUMMOD-SEL software to obtain the composition and texture of the sediment. The results of processing sediment samples at each station obtained that the grain size of sediments in the waters around Panjang Island ranged from -0.7 to 2.6 in the phi (φ) scale. Sediment composition consists of sand and gravel, with sand dominance of 89.1 %. Sediment textural classification consists of only 4 categories i.e. very coarse sand, coarse sand, medium sand, and fine sand. In general, the pattern of sediment distribution follows the pattern of water depth, where fine sand occupies deeper areas. Meanwhile, medium sand dominates surface sediment distribution in the study area
Microscopy Observation of Samosir Formation Paleosoil, Tuktuk Sidaong, North Sumatera, Indonesia.
No full textSamosir is the islands that emerge and standing upon on Toba Caldera after it’s the last eruption at 74.000 years ago. Samosir Island known as the caldera floor that uplifts parallel with Toba’s caldera flooding. In this study, we have observed an outcrop in Tumutuk, Samosir Island that hypothesized as a lacustrine deposit, and we found a paleosoil layer that might give more answers about the geological process in this area at the past time. Based on this outcrop, we described it, followed to measure its stratigraphy section, and took representative samples from the paleosoil layer, then observed the samples under the stereo-microscope as polish rock section, in normal light & negative images. As the result we identify several features of paleosoil & its sedimentary grain that shown this paleosoil layer, two events of the volcanoclastic deposits flown, and exposed two-time, and forming soil, it may form in the shallow swamp in a lacustrine environment, coincide with caldera flooding and caldera floor uplift event
Fluid Inclusion Study of Epithermal Quartz Veins from the Kyaukmyet Prospect, Monywa Copper-Gold Ore Field, Central Myanmar
Full text linkThe Kyaukmyet prospect is located near the main ore bodies of the Kyisintaung and Sabetaung high-sulfidation Cu-Au deposits, Monywa copper-gold ore field, central Myanmar. Lithologic units in the research area are of mainly rhyolite lava, lapilli tuff and silicified sandstone, mudstone and siltstone units of Magyigon Formation which hosted to be polymetallic mineralization. Our field study recorded that epithermal quartz veins are hosted largely in rhyolite lava and lapilli tuff units. Those quartz veins show crustiform, banded (colloform), lattice bladed texture and comb quartz. The main objectives of the present research in which fluid inclusion studies were considered to conduct the nature, characteristics and hydrothermal fluids evolution from the epithermal quartz veins. In this research, there are three main types of fluid inclusions are classified according to their phase relationship (1) two-phase liquid-rich inclusions, (2) the coexisting liquid-rich and vapor-rich inclusions, and (3) only vapor-rich inclusions. Microthermometric measurements of fluid inclusions yielded homogenization temperatures (Th) of 148–282 °C and final ice-melting temperature (Tm) of -0.2°C to -1.4°C . The value of (Tm) are equal to the salinities reaching up 0.35 to 2.07 wt % NaCl equiv. respectively. Estimation formation temperature of the quartz veins provide 190°C and 210°C and paleo-depth of formation are estimated to be between 130m and 210m. Petrography of fluid inclusion and microthermometric data suggest that fluid boiling as well as mixing processes were likely to be happened during the hydrothermal fluid evolution at the Kyaukmyet prospect. According to the characteristics of many parameters including petrography of fluid inclusion, microthermometric data, paleo-depth, evidence of quartz vein textures and types of hydrothermal alteration from the Kyaukmyet prospect allows to interpret these data to be the low-sulfidation epithermal system
Calcareous Nanofossil of Post-Gondwana Sequence in Southern Banda Arc, Indonesia
Full text linkThe presence of calcareous nannofossils in samples of the Post-Gondwana sequences (Kolbano and Viqueque sequence) gives guidance about the relative age of the study area located in the Outer Banda Arc, namely Timor, Rote, and Sawu Island. The study was carried out on six traverses, Timor Island traverse (Baun and Camplong), Rote Island traverse (Termanu and Central Rote), and Sawu Island traverses (West Sawu and East Sawu). There is 29 outcrop sample prepared using the smear slide method and observed using a polarizing microscope with 1000x magnification. The results of the study showed the presence of Cretaceous, Paleogene, and Neogen-Quarternary calcareous nannofossil. There are 82 species from 14 families identified in the post-Gondwana sequence. The results showed that the assemblage of calcareous nannofossil in Cretaceous characterized by the presence of Watznaueria fasciata, Watznaueria cynthae, Cyclagelosphaera brezae, Orastrum campanensis, and Micula concava. The assemblage of Paleogene calcareous nannofossil characterized by the presence of Coccolithus staurion, Chiasmolithus solitus, Discoaster minimus, Tawelus (?) magnicrassus, Chiasmolithus bidens, Prinsius africanus, Cyclicargolithus luminus, Spenolithus elongatus, Reticulofenestra umbilica, Cruciplacolithus vanheckae, and Helicospharea seminulum, and the assemblage of Neogene calcareous nannofossil characterized by the presence of Reticulofenestra pseudoumbilica, Discoaster quinqueramus, Helicosphaera princei, and Discoaster pansus. Quarternary calcareous nannofossil characterized by the presence of Ponthospaera indooceanica