Pub Date : 2023-06-30DOI: 10.55981/risetgeotam.2023.1247
A. Riyanto, D. Muslim, E. Yulianto, A. Krisnabudhi, Fuad Firmansyah
The geomorphological understanding of earth dynamics, including the relationship between landforms and their processes, was one of the earliest and most specific contributions to disaster prevention. Disaster geomorphology is one of the approaches in disaster studies, which includes aspects of landforms, processes, and results of physical processes that have the potential and can cause disasters. The landform is of risk factors that can turn natural hazards into natural disasters and determines the damage that disasters can cause to human activities. Following the 2006 South Java Tsunami, infrastructural development occurred massively in the 2006 South Java Tsunami inundation areas. Several tsunami risk mitigation efforts were conducted but solely based on the 2006 tsunami scenario and ignored the existence of more considerable tsunami hazards from the Sunda Megathrust. This consideration may lead to an increasing risk of future tsunamis. We evaluate and appraise favorable and unfavorable geomorphological features to reduce the risk of future tsunamis. Pangandaran has a unique landform compared to other areas on the south coast of Java, and this landform has the potential to reduce future tsunami risk. Typical landforms studied include coastal plains, alluvial plains, Tombolo, tied islands, and structural hills. The results show that the morphological features of the Tombolo and the coastal plain area are categorized as high risk when a tsunami occurs. The tied island is categorized as a favorable morphology where these morphological units have the advantage of elevation and efficient distance to the tsunami risk zone. Evacuation facilities are also needed, especially in the coastal plain and Tombolo areas (with a height of >20 meters), to reduce disaster risk, particularly mortality caused by tsunami events.
{"title":"Discerning geomorphological aspects of tsunami risk in Pangandaran, West Java, Indonesia","authors":"A. Riyanto, D. Muslim, E. Yulianto, A. Krisnabudhi, Fuad Firmansyah","doi":"10.55981/risetgeotam.2023.1247","DOIUrl":"https://doi.org/10.55981/risetgeotam.2023.1247","url":null,"abstract":"The geomorphological understanding of earth dynamics, including the relationship between landforms and their processes, was one of the earliest and most specific contributions to disaster prevention. Disaster geomorphology is one of the approaches in disaster studies, which includes aspects of landforms, processes, and results of physical processes that have the potential and can cause disasters. The landform is of risk factors that can turn natural hazards into natural disasters and determines the damage that disasters can cause to human activities. Following the 2006 South Java Tsunami, infrastructural development occurred massively in the 2006 South Java Tsunami inundation areas. Several tsunami risk mitigation efforts were conducted but solely based on the 2006 tsunami scenario and ignored the existence of more considerable tsunami hazards from the Sunda Megathrust. This consideration may lead to an increasing risk of future tsunamis. We evaluate and appraise favorable and unfavorable geomorphological features to reduce the risk of future tsunamis. Pangandaran has a unique landform compared to other areas on the south coast of Java, and this landform has the potential to reduce future tsunami risk. Typical landforms studied include coastal plains, alluvial plains, Tombolo, tied islands, and structural hills. The results show that the morphological features of the Tombolo and the coastal plain area are categorized as high risk when a tsunami occurs. The tied island is categorized as a favorable morphology where these morphological units have the advantage of elevation and efficient distance to the tsunami risk zone. Evacuation facilities are also needed, especially in the coastal plain and Tombolo areas (with a height of >20 meters), to reduce disaster risk, particularly mortality caused by tsunami events.","PeriodicalId":41045,"journal":{"name":"Riset Geologi dan Pertambangan","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89457318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-30DOI: 10.55981/risetgeotam.2023.1225
Muhammad Amin, S. Sudibyo, D. C. Birawidha, A. Rinovian, B. D. Erlangga, Muhammad Al Muttaqqi, E. G. Suka, Sherintia Pratiwi
Fly ash, bottom ash, and bentonite have potential to be used as geopolymer precursors, because they contain high silica and alumina. Until now there has been no research that combines these three materials as geopolymer materials. This research aims to incorporate bentonite as an aluminosilicate source in the fly ash and bottom ash based geopolymer. Geopolymer concrete was made by mixing precursors, alkaline activator, aggregate (gravel), superplasticizer, and water. The characterization of geopolymer concrete was carried out using XRD, XRF, and SEM-EDS. Then the compressive strength test was carried out. The SEM-EDS results show that the elements contained in geopolymer concrete are dominated by Si, Al, and O. The XRF results, the constituent compounds of geopolymer concrete are dominated by silica and alumina compounds. The XRD phase results formed are Quartz, Albite, and Hematite. The sample with code K6, which did not contain bentonite, had the highest compressive strength value of 9.57 MPa and 8.92 MPa at a drying time of 18 hours and 24 hours, respectively. This can happen because the addition of bentonite can reduce the retraction process. This also causes the porosity of the concrete to increase, thereby reducing its compressive strength.
{"title":"Effect of bentonite on fly ash and bottom ash based engineered geopolymer composite","authors":"Muhammad Amin, S. Sudibyo, D. C. Birawidha, A. Rinovian, B. D. Erlangga, Muhammad Al Muttaqqi, E. G. Suka, Sherintia Pratiwi","doi":"10.55981/risetgeotam.2023.1225","DOIUrl":"https://doi.org/10.55981/risetgeotam.2023.1225","url":null,"abstract":"Fly ash, bottom ash, and bentonite have potential to be used as geopolymer precursors, because they contain high silica and alumina. Until now there has been no research that combines these three materials as geopolymer materials. This research aims to incorporate bentonite as an aluminosilicate source in the fly ash and bottom ash based geopolymer. Geopolymer concrete was made by mixing precursors, alkaline activator, aggregate (gravel), superplasticizer, and water. The characterization of geopolymer concrete was carried out using XRD, XRF, and SEM-EDS. Then the compressive strength test was carried out. The SEM-EDS results show that the elements contained in geopolymer concrete are dominated by Si, Al, and O. The XRF results, the constituent compounds of geopolymer concrete are dominated by silica and alumina compounds. The XRD phase results formed are Quartz, Albite, and Hematite. The sample with code K6, which did not contain bentonite, had the highest compressive strength value of 9.57 MPa and 8.92 MPa at a drying time of 18 hours and 24 hours, respectively. This can happen because the addition of bentonite can reduce the retraction process. This also causes the porosity of the concrete to increase, thereby reducing its compressive strength. ","PeriodicalId":41045,"journal":{"name":"Riset Geologi dan Pertambangan","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90763781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-30DOI: 10.55981/risetgeotam.2023.1054
Rinaldi Ikhram, I. Syafri, Mega F. Rosana
The Ciletuh Mélange Complex in West Java, Indonesia, provides evidence of early Cenozoic subduction. This study aims to investigate the stratigraphic position, geological structure, metamorphic facies, and protoliths of the metamorphic rock units. The research methods employed geological mapping, petrology, and geochemical analysis. The samples collected exhibit different facies, including zeolites, greenschist, and epidote amphibolite. Protoliths consist of metasedimentary rocks such as metapellites, metapsammitics, meta-calcilates, and ortho-metamorphs such as metagabbro and metabasalt. Retrograde metamorphism, indicated by epidote, chlorite, and calcite in amphibolite schists, suggests lower temperature stress conditions. Hydrothermal changes are evidenced by some samples’ occurrence of quartz and calcite veins. Geochemical analysis reveals that the provenance of metasedimentary rocks originated from a volcanic arc, while the metabasalt rock originated from an island arc tectonic environment. K-Ar dating indicates an age range of 55.2 - 37.8 million years ago, corresponding to the Early to Late Eocene. These metamorphic rocks are believed to have formed through regional metamorphism due to island arc subduction and the formation of accretionary prisms. Retrograde metamorphism signifies uplift or accretion processes after tectonic activity.
{"title":"Petrology, Geochemistry and K-Ar Dating of Metamorphic Rock in Ciletuh Mélange Complex, West Java Indonesia","authors":"Rinaldi Ikhram, I. Syafri, Mega F. Rosana","doi":"10.55981/risetgeotam.2023.1054","DOIUrl":"https://doi.org/10.55981/risetgeotam.2023.1054","url":null,"abstract":"The Ciletuh Mélange Complex in West Java, Indonesia, provides evidence of early Cenozoic subduction. This study aims to investigate the stratigraphic position, geological structure, metamorphic facies, and protoliths of the metamorphic rock units. The research methods employed geological mapping, petrology, and geochemical analysis. The samples collected exhibit different facies, including zeolites, greenschist, and epidote amphibolite. Protoliths consist of metasedimentary rocks such as metapellites, metapsammitics, meta-calcilates, and ortho-metamorphs such as metagabbro and metabasalt. Retrograde metamorphism, indicated by epidote, chlorite, and calcite in amphibolite schists, suggests lower temperature stress conditions. Hydrothermal changes are evidenced by some samples’ occurrence of quartz and calcite veins. Geochemical analysis reveals that the provenance of metasedimentary rocks originated from a volcanic arc, while the metabasalt rock originated from an island arc tectonic environment. K-Ar dating indicates an age range of 55.2 - 37.8 million years ago, corresponding to the Early to Late Eocene. These metamorphic rocks are believed to have formed through regional metamorphism due to island arc subduction and the formation of accretionary prisms. Retrograde metamorphism signifies uplift or accretion processes after tectonic activity.","PeriodicalId":41045,"journal":{"name":"Riset Geologi dan Pertambangan","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82600668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-30DOI: 10.55981/risetgeotam.2023.1235
H. Rahmatulloh, M. Hadian, B. R. Suganda, R. Maria
The Baleendah – Soreang area is part of the southern part of the Bandung Soreang Groundwater Basin, constructed by volcanic activity. Regional development in the Baleendah – Soreang area can decrease groundwater quality, influenced by natural and anthropogenic factors. Groundwater hydrogeochemical analysis is important in environmental management studies. This study aims to determine groundwater’s physical properties and hydrogeochemical facies in this area. The groundwater hydrochemistry analysis, determined by analysis of Stiff diagrams and Piper diagrams, shows that the groundwater in the area is classified as freshwater and has intermediate groundwater flow. In addition, the groundwater quality is affected by some anthropogenic activities.
{"title":"Hydrogeochemical characteristics of groundwater in Baleendah - Soreang, South Bandung, West Java Province","authors":"H. Rahmatulloh, M. Hadian, B. R. Suganda, R. Maria","doi":"10.55981/risetgeotam.2023.1235","DOIUrl":"https://doi.org/10.55981/risetgeotam.2023.1235","url":null,"abstract":"The Baleendah – Soreang area is part of the southern part of the Bandung Soreang Groundwater Basin, constructed by volcanic activity. Regional development in the Baleendah – Soreang area can decrease groundwater quality, influenced by natural and anthropogenic factors. Groundwater hydrogeochemical analysis is important in environmental management studies. This study aims to determine groundwater’s physical properties and hydrogeochemical facies in this area. The groundwater hydrochemistry analysis, determined by analysis of Stiff diagrams and Piper diagrams, shows that the groundwater in the area is classified as freshwater and has intermediate groundwater flow. In addition, the groundwater quality is affected by some anthropogenic activities.","PeriodicalId":41045,"journal":{"name":"Riset Geologi dan Pertambangan","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91097825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-30DOI: 10.55981/risetgeotam.2023.1229
I. Permanajati, Annisa Helly Suranda, J. A. Zaenurrohman
Landslides are widespread natural disasters that occur across various areas in Indonesia. Among these areas, Pagentan and its surroundings in Banjarnegara Regency are identified as having significant potential for large-scale landslides. Therefore, this research was conducted to determine the susceptibility of ground movements. The method used to examine the surface geological mapping and analyze the soil movement susceptibility was the Spatial Multi-Criteria Evaluation (SMCE). This method is an applied science approach that employs spatial analysis and multi-criteria evaluation to support decision-making processes. Geological mapping was used to describe rocks, make geomorphological observations, measure geological structures, take stratigraphic sections, and collect rock samples. Multiple parameters were used to determine soil susceptibilities in the research area, such as slope, lithology, rock mass, elevation, land cover, road buffer, river buffer, and aspects, which were transformed into raster data for analysis. The susceptibility analysis classified the research area into four categories: low, medium, high, and very high. The low susceptibility zone includes Pandansari and Karangtengah. The moderate susceptibility zone includes Wonosroyo, Aribaya, Karangtengah, Pandansari, and Bantar. Most of the high susceptibility zones are in Bantar and Karangtengah. Meanwhile, the very high susceptibility zones include Gumingsir, Plumbungan, Kalitlaga, Kayuares, Nagasari, Karangnangka and Mentawana.
{"title":"Assessment of Landslide Susceptibility in the Pagentan Area, Banjarnegara Regency: A Spatial Multi-Criteria Evaluation Approach","authors":"I. Permanajati, Annisa Helly Suranda, J. A. Zaenurrohman","doi":"10.55981/risetgeotam.2023.1229","DOIUrl":"https://doi.org/10.55981/risetgeotam.2023.1229","url":null,"abstract":"Landslides are widespread natural disasters that occur across various areas in Indonesia. Among these areas, Pagentan and its surroundings in Banjarnegara Regency are identified as having significant potential for large-scale landslides. Therefore, this research was conducted to determine the susceptibility of ground movements. The method used to examine the surface geological mapping and analyze the soil movement susceptibility was the Spatial Multi-Criteria Evaluation (SMCE). This method is an applied science approach that employs spatial analysis and multi-criteria evaluation to support decision-making processes. Geological mapping was used to describe rocks, make geomorphological observations, measure geological structures, take stratigraphic sections, and collect rock samples. Multiple parameters were used to determine soil susceptibilities in the research area, such as slope, lithology, rock mass, elevation, land cover, road buffer, river buffer, and aspects, which were transformed into raster data for analysis. The susceptibility analysis classified the research area into four categories: low, medium, high, and very high. The low susceptibility zone includes Pandansari and Karangtengah. The moderate susceptibility zone includes Wonosroyo, Aribaya, Karangtengah, Pandansari, and Bantar. Most of the high susceptibility zones are in Bantar and Karangtengah. Meanwhile, the very high susceptibility zones include Gumingsir, Plumbungan, Kalitlaga, Kayuares, Nagasari, Karangnangka and Mentawana.","PeriodicalId":41045,"journal":{"name":"Riset Geologi dan Pertambangan","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82465121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-30DOI: 10.14203/risetgeotam2022.v32.1214
N. Anatoly, Siti Rofikoh
One of the most critical aspects of open pit mining is the dewatering and mine drainage systems. The NCP Open Pit Gold Mine is located in Central Kalimantan. This study area has a range of rainfall intensities and durations from moderate to heavy. Good dewatering is required to manage runoff water and reduce runoff from entering the pit and mine front loading. The study used daily rainfall intensity data from 1994 to 2018. Using the Mononobe Method, the hydrological data for this area were evaluated by determining the value of the rainfall intensity plan. According to the evaluation of rainfall data from 1994 to 2018, the research area saw a rainfall intensity of 86.23 mm/day over a two-year return period. The majority of water extracted from mines is from precipitation and runoff rather than groundwater. An open channel was made around the open pit, flowing water naturally into the sump to reduce water entering the mining area. The water was pumped into the settling pond with 520 m3/hour and 780 m3/hour capacity pumps.
{"title":"Dewatering requirements assessment for the Central Kalimantan NCP open pit gold mine","authors":"N. Anatoly, Siti Rofikoh","doi":"10.14203/risetgeotam2022.v32.1214","DOIUrl":"https://doi.org/10.14203/risetgeotam2022.v32.1214","url":null,"abstract":"One of the most critical aspects of open pit mining is the dewatering and mine drainage systems. The NCP Open Pit Gold Mine is located in Central Kalimantan. This study area has a range of rainfall intensities and durations from moderate to heavy. Good dewatering is required to manage runoff water and reduce runoff from entering the pit and mine front loading. The study used daily rainfall intensity data from 1994 to 2018. Using the Mononobe Method, the hydrological data for this area were evaluated by determining the value of the rainfall intensity plan. According to the evaluation of rainfall data from 1994 to 2018, the research area saw a rainfall intensity of 86.23 mm/day over a two-year return period. The majority of water extracted from mines is from precipitation and runoff rather than groundwater. An open channel was made around the open pit, flowing water naturally into the sump to reduce water entering the mining area. The water was pumped into the settling pond with 520 m3/hour and 780 m3/hour capacity pumps.","PeriodicalId":41045,"journal":{"name":"Riset Geologi dan Pertambangan","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2022-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74630347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-30DOI: 10.14203/risetgeotam2022.v32.1195
D. Sarah
Land subsidence has become a significant silent hazard in the big cities across Indonesia that aggravates future sustainable development. Land subsidence hazards hard-hit Java as the most densely populated island. This paper reviews Indonesia’s land subsidence hazards, particularly subsidence cases across the big cities on Java Island, Jakarta, Semarang, and Bandung. Generally, land subsidence research in Indonesia can be categorized into two broad focuses: monitoring subsidence rate and investigating land subsidence mechanism. This paper aims to present a comprehensive summary of the current status of land subsidence research in Indonesia and discusses the challenging issues encountered in research and mitigation measures. A qualitative literature review was used in this study for reviewed articles in the Google Scholar database published in Indonesian and English up to 2020. Land subsidence in Jakarta, Bandung, and Semarang is still ongoing at a high rate. Its mechanism is highly influenced by excessive groundwater withdrawal, although other natural and anthropogenic factors also play a part. This review proposes recommendations to alleviate the impacts of land subsidence hazards in Indonesia and for further research
{"title":"Land subsidence hazard in Indonesia: Present research and challenges ahead","authors":"D. Sarah","doi":"10.14203/risetgeotam2022.v32.1195","DOIUrl":"https://doi.org/10.14203/risetgeotam2022.v32.1195","url":null,"abstract":"Land subsidence has become a significant silent hazard in the big cities across Indonesia that aggravates future sustainable development. Land subsidence hazards hard-hit Java as the most densely populated island. This paper reviews Indonesia’s land subsidence hazards, particularly subsidence cases across the big cities on Java Island, Jakarta, Semarang, and Bandung. Generally, land subsidence research in Indonesia can be categorized into two broad focuses: monitoring subsidence rate and investigating land subsidence mechanism. This paper aims to present a comprehensive summary of the current status of land subsidence research in Indonesia and discusses the challenging issues encountered in research and mitigation measures. A qualitative literature review was used in this study for reviewed articles in the Google Scholar database published in Indonesian and English up to 2020. Land subsidence in Jakarta, Bandung, and Semarang is still ongoing at a high rate. Its mechanism is highly influenced by excessive groundwater withdrawal, although other natural and anthropogenic factors also play a part. This review proposes recommendations to alleviate the impacts of land subsidence hazards in Indonesia and for further research","PeriodicalId":41045,"journal":{"name":"Riset Geologi dan Pertambangan","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2022-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78626227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-30DOI: 10.14203/risetgeotam2022.v32.1183
Ruri Pitaloka, A. Saepuloh, Slamet Sugiharto
This article is about a visual investigation of paleochannel identification using ALOS 2 PALSAR 2 (Advanced Land Observing Satellite 2 Phased Array type L-band Synthetic Aperture Radar 2) radar satellite image. The radar image has a higher layer-penetration ability than the optical image so that the characteristics of near-surface materials are possible to be detected, including the morphology of the abandoned river stream. The purpose of ancient channels investigation is to localize potential areas of tin placer deposits, including rare earth elements as associated minerals. This investigation was aided by LANDSAT 8 optical image and National Digital Elevation Model (DEMNAS) data. Visual identification has been performed based on the shape, color, pattern, texture, and position against other morphologies in the image. The criteria for paleochannels are the channels detected using ALOS 2 PALSAR 2 image but not in LANDSAT 8 optical image and DEMNAS data. Based on these criteria, eleven traces of paleochannels have been well identified. Their occurrences are generally associated with meanders, open areas, and near the coast. The detected paleochannels are generally purple to dark in the color composite of the ALOS 2 PALSAR 2 image. These detected rivers are in pink to purplish-green zones and have a random appearance.
{"title":"Investigation of paleochannel identification using radar and optical images on placer deposits in Bangka Barat Regency, Indonesia","authors":"Ruri Pitaloka, A. Saepuloh, Slamet Sugiharto","doi":"10.14203/risetgeotam2022.v32.1183","DOIUrl":"https://doi.org/10.14203/risetgeotam2022.v32.1183","url":null,"abstract":"This article is about a visual investigation of paleochannel identification using ALOS 2 PALSAR 2 (Advanced Land Observing Satellite 2 Phased Array type L-band Synthetic Aperture Radar 2) radar satellite image. The radar image has a higher layer-penetration ability than the optical image so that the characteristics of near-surface materials are possible to be detected, including the morphology of the abandoned river stream. The purpose of ancient channels investigation is to localize potential areas of tin placer deposits, including rare earth elements as associated minerals. This investigation was aided by LANDSAT 8 optical image and National Digital Elevation Model (DEMNAS) data. Visual identification has been performed based on the shape, color, pattern, texture, and position against other morphologies in the image. The criteria for paleochannels are the channels detected using ALOS 2 PALSAR 2 image but not in LANDSAT 8 optical image and DEMNAS data. Based on these criteria, eleven traces of paleochannels have been well identified. Their occurrences are generally associated with meanders, open areas, and near the coast. The detected paleochannels are generally purple to dark in the color composite of the ALOS 2 PALSAR 2 image. These detected rivers are in pink to purplish-green zones and have a random appearance.","PeriodicalId":41045,"journal":{"name":"Riset Geologi dan Pertambangan","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2022-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78317408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-30DOI: 10.14203/risetgeotam2022.v32.1213
Muhammad Razzaaq Al Ghiffari, L. Widodo
The Cisangkuy sub-watershed is part of the Citarum watershed with ±300 km of river length. The total area is in line with the potential of water resources which is quite good, but over time the hydrological condition of the site has decreased. Decreasing the hydrological state is due to changes in land use and land cover from year to year and is indicated by high discharge and flooding in the rainy season. This study aims to find the optimal location of artificial recharge to maintain water balance in the Cisangkuy sub-watershed. Fuzzy logic is used for determining the location of artificial recharge by considering the input variable DRASTIC in the form of depth to groundwater level, net recharge, aquifer media, soil type, slope, vadose zone, and hydraulic conductivity. In addition, subtractive clustering is performed to obtain the class of each DRASTIC parameter. Furthermore, a genetic algorithm is carried out to get the optimal location of the artificial recharge zone. The priority zone is indicated by the high class of each DRASTIC parameter input. Combined fuzzy logic and genetic algorithm show that the optimal location for artificial recharge is in the northern part of the Cisangkuy sub-watershed, precisely in the Banjaran area.
{"title":"Site selection for artificial recharge in Cisangkuy sub-watershed, West Java, using combined fuzzy logic and genetic algorithm","authors":"Muhammad Razzaaq Al Ghiffari, L. Widodo","doi":"10.14203/risetgeotam2022.v32.1213","DOIUrl":"https://doi.org/10.14203/risetgeotam2022.v32.1213","url":null,"abstract":"The Cisangkuy sub-watershed is part of the Citarum watershed with ±300 km of river length. The total area is in line with the potential of water resources which is quite good, but over time the hydrological condition of the site has decreased. Decreasing the hydrological state is due to changes in land use and land cover from year to year and is indicated by high discharge and flooding in the rainy season. This study aims to find the optimal location of artificial recharge to maintain water balance in the Cisangkuy sub-watershed. Fuzzy logic is used for determining the location of artificial recharge by considering the input variable DRASTIC in the form of depth to groundwater level, net recharge, aquifer media, soil type, slope, vadose zone, and hydraulic conductivity. In addition, subtractive clustering is performed to obtain the class of each DRASTIC parameter. Furthermore, a genetic algorithm is carried out to get the optimal location of the artificial recharge zone. The priority zone is indicated by the high class of each DRASTIC parameter input. Combined fuzzy logic and genetic algorithm show that the optimal location for artificial recharge is in the northern part of the Cisangkuy sub-watershed, precisely in the Banjaran area.","PeriodicalId":41045,"journal":{"name":"Riset Geologi dan Pertambangan","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2022-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79246296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-30DOI: 10.14203/risetgeotam2022.v32.1218
A. Farisan, M. G. Rachman
Bayat, Klaten, Central Java, is one of three locations in Java with complete types of rocks exposed at the earth’s surface. All those rocks are scattered over a short distance in Bayat, revealing past processes of rock deformation (folding, fracturing, and faulting) and present-day processes of rock weathering and erosion. In this study, we present how clastic carbonate rock of the Oyo Formation at northern Jiwo Hills could be separated about ±15 km northern from its platforms as an indication of thrust fault growth. This study uses aerial photography for photogrammetry (drones) combined with structural geology and microfossil analyses (to know the exact formation) from the outcrop observation. Recent studies have certified that drones are one reliable observation tool in various aspects with better resolution, especially in structural geology studies. Aerial photogrammetry is very well done to see the exact condition of a wide area combined with high resolution on an outcrop scale. The result shows that the carbonate rocks are from Oyo Formation (N9–N11) with the Middle Neritic bathymetric zone. The structural geology phenomenon kinematically indicates the impact of the transpressional movement called flower structure. Based on subsurface interpretation, the authors hypothesize this area was the product of an imbrication thrust stack uplifted basement as the result of the thrust fault rather than horst or paleo-basement high.
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