Journal of Geoscience, Engineering, Environment, and Technology
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Clean Water Supply in Tasikmalaya Municipality, Opportunities and Challenges
Full text linkCurrently, there are three sub-districts in Tasikmalaya City that are still vulnerable to clean water, namely Kawalu, Tamansari, and Cibeureum sub-districts. PDAM Tirta Sukapura, owned by the Tasikmalaya Regency Government, has not been able to meet clean water needs, so the Tasikmalaya Municipality Government plans to build a new PDAM as an alternative. The Ciwulan river in Cibeuti Village is a source of water that will be used as a collection point. Rain data was taken from 2 stations, namely Gunung Satria and Cikunten II stations, for ten years. The evapotranspiration value was calculated using the Penman-Monteith method. The calculation of the discharge in the intake area, namely Ciwulan-Cibeuti with a watershed area of 405 km2, used the NRECA method using parameters taken from the calibrated Ciwulan-Sukaraja station. The calibration parameters are PSUB = 0.86; GWF = 0.22, reduction coefficient = 0.80; and NSE = 0.764. The determination of the dependable flow is calculated using the Weibull method. The magnitude of the Q90's dependable flow is 4.3 m3/s. The projected population for the next 15 years is estimated at 307,857 people, so the amount of water needed is around 0.535 m3/s. Opportunities for business entities to participate in building PDAM are wide open, with the certainty of return plus profits or independent management by business entities within a certain period of time. The challenge for the government and business entities is to provide reasonable prices to customers and new networks
Control Structure On Damage Zone and Fault Plane to Geometry Of Quartz Veins and Calcite In Muaradua Ogan Komering Ulu Selatan, South Sumatra, Indonesia
Full text linkGeological mapping was carried out on the Gilas and Malau rivers in the Muaradua area, South Ogan Komering Ulu Regency, South Sumatra by observing the presence of joints, faults, and veins in the granite and phyllite rock outcrops of the Tarap Formation. Research on pattern geometry and vein type in the crushing zone is focused on measuring the direction (trend) of veins and joints. The measurement results are then analyzed to obtain a general pattern of quartz and calcite veins so that the orientation of their development can be known. The method used in this study is in the form of determining the orientation and geometry of the veins based on classifications that refer to several studies, then an analysis is carried out using DemNAS data to determine the general direction of the straightness pattern of the study area. The quartz veins that developed in the study area have an extensional fracture type with the geometry found in the form of isolated, abutting, cutting, mutually-cutting, and crosscutting. The veins that develop in the research area are relatively north-south and west-east and indicated the presence of a fault and traces of deformation that occurred in the study area. With the help of veins and joints found in the study area, it is possible to determine the structural control of the presence of a crushing zone in the fault plane
Identification of Potential Geotourism Destination in the River Subayang areas of Kampar, Riau, Indonesia
Full text linkThe readiness of an area to be able to develop tourism potential as geotourism is seen from various aspects, including the existing geological heritage, as well as the enthusiasm of the local community which is the main focus in creating good geotourism, while the government acts as the main mover. In Kampar Regency, Riau Province, to be precise in the Sushadow River area, the Rimbang Balling area located in the Kampar Kiri Hulu sub-district, there are natural attractions that the Subayang river passes through, in addition to the river being so clear, upstream we can find a stone wall waterfall, possibly having a waterfall. This paper, shows the potential of geotourism froum various aspects of geomorphology and community life, such as economic, social, cultural and infrastructure and discusses the role of society and sectors as tourism actors in subayang river using the RAP-fish method. Geotourism studies can be drawn from various integrations of existing theories, conceptual analyzes and practices of nature-based tourism and closer collaboration with relevant social sciences so that they can play a role in the promotion of tourism among the public and professionals
Effects of Corn Stalks Ash as A Substitution Material of Cement Due to the Concrete Strength of Rigid Pavement
Full text linkCement is an adhesive material for concrete mixtures in addition to water, fine and coarse aggregates. One of the main ingredients of cement is silica (SiO2) which is originated from the earth's crust. Silica is also available in plants such as corn stalks. This research is aimed to utilize the corn stalk ash (CSA) as an alternative substitution for some cement in concrete for the rigid pavement of road construction. According to the Indonesian standard, the flexural tensile strength should be exceeded at least 4.5 MPa. The flexural tensile strength has also a correlation due to compressive strength.
The concrete materials consisted of the coarse aggregate (river crushed stone) from Kampar River and Danau Bingkuang sands from Kampar District of Riau Province, and Portland Composite Cement from Semen Padang. The CSA was made by burning the dried corn stalks in a steel cylinder can over 24 hours. The content of CSA was varied by 0%, 5%, 7% and 9%. The compressive strength design of concrete was 31,3 MPa. Testing procedures were based on the Indonesian Standard for concrete. The tested specimens have consisted of cube specimens (150 mm x 150 mm x 150 mm) for compressive tests, and beam specimens (150 mm x 150 mm x 600 mm) for flexural strength tests. All specimens were tested on 28 days-age.
The results show that CSA can be used as a partial substitution of cement in concrete. The addition of CSA tends to increase the compressive strength of concrete instead of its flexural tensile strength. The optimum content of CSA was 7% and resulted in an 8.0% and 6.9% increase in compressive and flexural tensile strength due to design respectively. Compressive and flexural tensile strength fulfilled the standard. Flexural tensile strength is obtained by 15% of the compressive strength. Cornstalk ash can be used as a substitution of cement for rigid pavement concrete. It can reduce the utilization of cement and will be potentially cost efficiency
Rapid Land Cover Change in The South Sumatera Peat Area Associated With 2015 Peat Fires
Full text linkThe peat fire events in Indonesia, particularly the South Sumatra area, changed the appearance of surface vegetation. The fires usually occur during the dry season from July to October. This study aims to evaluate land cover changes due to 2015’s peat fire in the South Sumatra peatlands. Remote sensing techniques using a Normalized Difference Vegetation Index (NDVI) method were used to identify the change of vegetation density in the study area. The results showed that 69% of the total South Sumatra peatland was burned due to the 2015 peat fire event. The level of vegetation density was considerably decreased by fire events. The degradation in the burned area was dominated by land cover class of ferns/shrub. The Peat fires during the observation period have a negative impact on the peat ecosystem, so improvements are needed in peatland management practices. Improvements need to be made in fire prevention and management practices, as well as restoration of burnt land
Evolution Magmatism of Nagasari Volcano Dieng, Central Java, Indonesia
Full text linkNagasari Volcano, part of the Dieng volcanic complex, is one of the unique volcanoes in Central Java. Around this volcano grow eruption craters, volcanic cones, and pyroclastic flow ridges. There were several 14 eruption centers around Mount Nagasari, so it is necessary to know the development of magmatism evolution. The aims of the research to determine the evolutionary development of magmatism. The methodology used is geological mapping and petrographic analysis. The observations of rocks found in the study area include andesite lava, lapilli-tuff, fallen pyroclastic breccias, and flow pyroclastic breccias. Meanwhile, geological mapping and petrographic observations of volcanic rock samples show that the evolution of magmatism in the study area from the oldest to the youngest is basaltic magma that formed Prau Volcano in the pre-caldera period. On the other hand, magmatism in the post-caldera I period was of the type of pyroxene andesite forming the Gembol to Jimat Volcano group. In contrast, in the post-caldera II period, the hornblende-biotite andesite group formed the Dieng Kulon to Kendil group
Temporal variation in sandstone composition of Miocene Jatiluhur Formation in the Bogor Trough, West Java, Indonesia
Full text linkBogor Trough in the West Java are typified by turbidity deposits with the source are mostly characterized by volcanoclastic materials from the southern area. The Trough actually receipt the sediment from both volcanoclastic materials from the south and continental source from the north. But, the discussions of sediments in term of composition and temporal variation are rare to be reported, especially the sediments from the north. This manuscript intends to discuss the temporal variation in detrital compositional and depositional facies of the Neogene sediments that delivered from the north (i.e., Sundaland) into the Bogor Trough, which is represented by Miocene Jatiluhur Formation.
A total of 36 selected samples have been taken for identifying the minerals using a polarization microscope. Modal analysis of the Gazzi-Dickinson method was applied for this provenance study of sandstones samples, which are consisting largely of quartz and feldspar, then sedimentary rock and volcanic rock fragments, glaucony, mud chips and skeletal fragments.
Sundaland, a continental block highland area in the north, is interpreted to have been the provenance of sediments of the Jatiluhur Formation, which is also considered to be the source area for the Paleogene sediments. Granitic igneous rocks are interpreted as the source of dominance of monocrystalline quartz grains, or the product of long-distance transport of polycrystalline quartz from metamorphic rocks
But, however late Miocene samples (upper part of formation) represent that the size and amount of glauconite grains are increasing, and texturally mud supported. Volcanic rocks materials are also observed. The upper part of Jatiluhur Formation records the starvation of sediment discharge into the basin, which has been also promoted for development of carbonate reef Klapanunggal Formation in the self-margin setting, and suggesting that the basin have directly received or indirectly some contemporaneous volcanic provenances sediment from the southern area
Residual Strength Parameter Method for Slope stability on a Toll Road with Expansive Clay
Full text linkThe decreasing stability phenomenon needs to be considered during the design of cut slopes on problematic soil. Excavation slope of toll road construction tends to fail when it lies above clay-shale strata. Certain common correlations and ordinary analytical methods are not recommended for safety calculation. This study is intended to find out the characteristic of clay-shale and proper slope inclination design on Semarang Batang Toll Road. The behaviour of a clay-shale area on the cut slope of Batang-Semarang toll road segment STA 438+000–STA 439+000 was identified. The degradable and expansive properties caused slope failure of the initial design with an inclination of 1 H: 1 V. Laboratory tests found that the soil had a clay faction > 40% and can be categorized as high plasticity (LL > 50%). An empirical approach determined that the residual shear strength decreased to phi < 6 degrees. To describe the swelling after the excavation stage, the flow deformation was determined by a finite element simulation. During the swelling phase, the pore water pressure was maintained at a certain value, and a gentler slope fulfilled the minimum safety factor with an inclination of 1 V: 3 H. Furthermore, the shear strength of the clay-shale was reduced to that for a fully softened material, and all the slope factors for safety moved to a critical state. According to the simulation, the minimum suggested slope inclination is 5 H: 1 V. This approach is important for the maintenance of pore water pressure and the prevention of an additional reduction in the shear strength so as to avoid slope failure on clay-shale regions in the yielding stage
Laboratory Study On The Utilization of Jackruit Skin Waste Into Car-boxymethyl Cellulose and Their Effect On The Rheological Properties Of Drilling Mud
Full text linkThe value rheology of drilling mud must be in accordance with the conditions of wellbore that do not lead to the occurrence of the problems at the time of drilling. One of the efforts to improve the rheology of drilling mud is by adding Carboxymethyl Cellulose (CMC) which is useful for increasing viscosity and binding water. This study aims to identify the effect on the use of CMC originating from jackfruit skin to the rheological properties of drilling mud. Jackfruit skin is an underutilized organic waste and the structure of jackfruit skin contains 50-55% cellulose. Manufacturing phase of synthesizing CMC skin jackfruit includes the process of delignification, alkalization, carboximetilation, and sieve sample to be powdered CMC and subsequently carried out the test of plastic viscosity, yield point , gel strength by using a Fann VG Meter and mud cake using a marsh funnel and volume filtration using a filter press . The added mass of CMC jackfruit skin were varied from 1 g, 2 g, 3 g, 4 g to 5 g. The results suggest that the addition of jackfruit skin CMC has an effect on the rheology of drilling mud. Increasingly many additions additive CMC skin jackfruit who use the increasingly high- value rheology mud drilling were obtained. Furthermore, the addition of CMC jackfruit skin starting from 1gr – 5 gr meets the API 13, a standard for the value of yield point/viscosity plastic, plastic viscosity and maximum volume of filtrate. While the value of gel strength which meets the API 13 A is with the addition of CMC jackfruit skin as much as 5 grams