scholarly journals Identification of alteration zones using a Landsat 8 image of densely vegetated areas of the Wayang Windu Geothermal field, West Java, Indonesia

2019 ◽  
Vol 254 ◽  
pp. 012004
Author(s):  
Kristian Edwin Salamba ◽  
Arie Naftali Hawu Hede ◽  
Mohamad Nur Heriawan
Keyword(s):  
Geothermal Field ◽  
Landsat 8 ◽  
West Java ◽  
Alteration Zones

Chemical and physical characteristic of patuha geothermal field manifestations, West Java, Indonesia

2021 ◽  
Author(s):  
Zahra Nuraini Hadna ◽  
Agung Harijoko ◽  
Khasani ◽  
Randy Wijaya Atmaja
Keyword(s):  
Physical Characteristic ◽  
Geothermal Field ◽  
West Java

Reservoir management at Awibengkok geothermal field, West Java, Indonesia

Geothermics ◽  
2008 ◽  
Vol 37 (3) ◽  
pp. 332-346 ◽  
Author(s):  
Jorge A. Acuña ◽  
James Stimac ◽  
Lutfhie Sirad-Azwar ◽  
Riza Glorius Pasikki
Keyword(s):  
Reservoir Management ◽  
Geothermal Field ◽  
West Java

scholarly journals Geological mapping and mineral prospectivity using remote sensing and GIS in parts of Hamissana, Northeast Sudan

2021 ◽  
Vol 11 (3) ◽  
pp. 1123-1138
Author(s):  
Mohamed Taha AlMakki Mohamed ◽  
Latifa Shaheen Al-Naimi ◽  
Tochukwu Innocent Mgbeojedo ◽  
Chidiebere Charles Agoha
Keyword(s):  
Remote Sensing ◽  
Gold Mineralization ◽  
Principal Component ◽  
Original Data ◽  
Wall Rock ◽  
Geological Mapping ◽  
Landsat 8 ◽  
Alteration Zones ◽  
Wall Rock Alteration ◽  
Rock Alteration

AbstractIn recent years, various geological activities and different mineral prospecting and exploration programs have been intensified along the Red Sea hills in order to elucidate the geological maps and to evaluate the mineral potentials. This study is therefore aimed at testing the viability of using remote sensing and geographic information system (GIS) techniques for geological mapping and prospecting for gold mineralization in the area. The study area is located in northeast Sudan and covers an area of about 1379 km2. Different digital image processing techniques were applied to Landsat 8 Operational Land Imager image in order to increase the discrimination between various lithological units and to delineate wall rock alteration which represents target zones for gold mineralization. Image sharpening was performed to enhance the spatial resolution of the images for more detailed information. Contrast stretching was applied after the various digital processing procedures to produce more interpretable images. The principal component analysis transformations yielded saturated images and resulted in more interpretable images than the original data. Several ratio images were prepared, combined together and displayed in RGB color composite ratio images. This process revealed the existence of alteration zones in the study area. These zones extend from the northeast to the southwest in the acid meta-volcanic and silica barite rocks. The enhanced satellite images were implemented in the GIS environment to facilitate the final production of the geological map at scale 1:400,000. X-ray fluorescence analyses prove that selected samples taken from the wall rock alteration zones are gold-bearing.

scholarly journals HYDROTHERMAL ALTERATION ZONES DETECTION IN LIMNOS ISLAND, THROUGH THE APPLICATION OF REMOTE SENSING

2017 ◽  
Vol 50 (3) ◽  
pp. 1596 ◽  
Author(s):  
A. Anifadi ◽  
Is. Parcharidis ◽  
O. Sykioti
Keyword(s):  
Hydrothermal Alteration ◽  
Field Work ◽  
High Spectral Resolution ◽  
General Distribution ◽  
Spectral Signature ◽  
Landsat 8 ◽  
Alteration Zones ◽  
Multispectral Data ◽  
Band Ratios ◽  
Hydrothermal Alteration Zones

In this study we use Landsat 8 OLI satellite imagery in order to identify and map alteration zones in Limnos island (N. Aegean, Greece). Pre-processing included sea and vegetation masking. In order to enhance spatial resolution, data fusion to 15m is performed. A lineament map is extracted from the panchromatic image that gives the general tectonic view of the island. The detection and mapping of alteration minerals is performed using specific band ratios and consequent composite images. The colour composite using bands 10, 11, 7 (RGB) show the spectral signature and general distribution of silica. Band ratios 6/7, 4/2, 6/5, reveal alteration zones containing iron oxides, clay alteration and ferrous minerals correspondingly. The aforementioned analysis has shown that hydrothermally alteration areas in Limnos are located in the west part of the island and at the Fakos Peninsula, Sardes, Roussopouli and Paradeisi hill. These areas are compared and validated with the reported field work. We conclude that hydrothermal alteration zones can indeed be detected and mapped using medium resolution satellite multispectral data. However, for the identification and mapping of specific types of rocks and minerals, a sensor with high spectral resolution is required. 

scholarly journals Comparison of Different Multispectral Images to Map Hydrothermal Alteration Zones in Kokap, Kulon Progo

2021 ◽  
Vol 6 (2) ◽  
pp. 86
Author(s):  
Bayu Raharja ◽  
Agung Setianto ◽  
Anastasia Dewi Titisari
Keyword(s):  
Remote Sensing ◽  
Hydrothermal Alteration ◽  
Remote Sensing Data ◽  
Component Analysis ◽  
Landsat 8 ◽  
Accuracy Evaluation ◽  
Multispectral Images ◽  
Band Ratio ◽  
Alteration Zones ◽  
Sentinel 2

Using remote sensing data for hydrothermal alteration mapping beside saving time and reducing  cost leads to increased accuracy. In this study, the result of multispectral remote sensing tehcniques has been compare for manifesting hydrothermal alteration in Kokap, Kulon Progo. Three multispectral images, including ASTER, Landsat 8, and Sentinel-2, were compared in order to find the highest overall accuracy using principle component analysis (PCA) and directed component analysis (DPC). Several subsets band combinations were used as PCA and DPC input to targeting the key mineral of alteration. Multispectral classification with the maximum likelihood algorithm was performed to map the alteration types based on training and testing data and followed by accuracy evaluation. Two alteration zones were succeeded to be mapped: argillic zone and propylitic zone. Results of these image classification techniques were compared with known alteration zones from previous study. DPC combination of band ratio images of 5:2 and 6:7 of Landsat 8 imagery yielded a classification accuracy of 56.4%, which was 5.05% and 10.13% higher than those of the ASTER and Sentinel-2 imagery. The used of DEM together with multispectral images was increase the accuracy of hydrothermal alteration mapping in the study area.

scholarly journals The Hydrothermal Alteration of the Cordón de Inacaliri Volcanic Complex in the Framework of the Hidden Geothermal Systems within the Pabelloncito Graben (Northern Chile)

Minerals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1279
Author(s):  
Santiago Nicolás Maza ◽  
Gilda Collo ◽  
Diego Morata ◽  
Carolina Cuña-Rodriguez ◽  
Marco Taussi ◽  
...  
Keyword(s):  
Hydrothermal Alteration ◽  
Geothermal Field ◽  
Geothermal System ◽  
Volcanic Complex ◽  
Geothermal Systems ◽  
Acid Sulfate ◽  
Alteration Zones ◽  
Geological Processes ◽  
Freshwater Bodies ◽  
Hydrothermal Alteration Zones

Detailed mineralogical analyses in areas with surface hydrothermal alteration zones associated with recent volcanism (<1 Ma) in the Central Andean Volcanic Zone could provide key information to unravel the presence of hidden geothermal systems. In the Cordón de Inacaliri Volcanic Complex, a geothermal field with an estimated potential of ~1.08 MWe·km−2 has been recently discovered. In this work, we focus on the hydrothermal alteration zones and discharge products of this area, with the aim to reconstruct the geological processes responsible for the space-time evolution leading to the geothermal records. We identified (1) discharge products associated with acid fluids that could be related to: (i) acid-sulfate alteration with alunite + kaolinite + opal CT + anatase, indicating the presence of a steam-heated blanket with massive fine-grained silica (opal-CT), likely accumulated in mud pots where the intersection of the paleowater table with the surface occurred; (ii) argillic alteration with kaolinite + hematite + halloysite + smectite + I/S + illite in the surrounding of the acid-sulfate alteration; and (2) discharge products associated with neutral-alkaline fluids such as: (i) discontinuous pinnacle-like silica and silica deposits with laterally developed coarse stratification which, together with remaining microorganisms, emphasize a sinter deposit associated with alkaline/freshwater/brackish alkaline-chlorine water bodies and laterally associated with (ii) calcite + aragonite deriving from bicarbonate waters. The scarce presence of relics of sinter deposits, with high degree crystallinity phases and diatom remnants, in addition to alunite + kaolinite + opal CT + anatase assemblages, is consistent with a superimposition of a steam-heated environment to a previous sinter deposit. These characters are also a distinguishing feature of paleosurface deposits associated with the geothermal system of the Cordón de Inacaliri Volcanic Complex. The presence of diatoms in heated freshwater bodies at 5100 m a.s.l. in the Atacama Desert environment could be related with the last documented deglaciation in the area (~20–10 ka), an important factor in the recharge of the hidden geothermal systems of the Pabelloncito graben.

scholarly journals Identification and analysis of shoreline changes over fishermen settlement along the coast of sungaibuntu and cemarajaya village, Karawang Regency, West Java

2021 ◽  
Vol 72 (1) ◽  
pp. 95-106
Author(s):  
Ikhsani A. ◽  
Sudjono P. ◽  
Firdayati M. ◽  
Marselina M.
Keyword(s):  
Environmental Sustainability ◽  
Mean Value ◽  
Tidal Range ◽  
Significant Feature ◽  
Landsat 8 ◽  
Economic Activities ◽  
Negative Effects ◽  
West Java ◽  
Shoreline Changes ◽  
Landsat 7

Shoreline changes, that occur along the coast, gives negative effects to the environment and also social-economic activities on the fishermen’s livelihood. Study about shoreline changes, its trends, and its causes are important for the development of economic and sanitation vulnerability assessment on fishermen community caused by shoreline changes. Thus, environmental sustainability criteria within the local scale and specific to fishermen community takes into account and the implementation of the instrument become more appropriate to reduce the undesirable effects. This research aims to identifying and analysing shoreline changes trend and its factors over the fishermen settlement area along the coast of Sungaibuntu and Cemarajaya village, Karawang Regency, West Java. Data used in this study are Landsat-7 1999, 2002, 2007, and 2012 as well as Landsat-8 2017. To enhance Landsat-7 images, band 2-4-5 are used, meanwhile Landsat-8 employs band 3-5-6. Later, the shoreline was extracted by applying band rationing techniques, Band2/Band5 for Landsat-7 and Band3/Band6 for Landsat-8. The rate of shoreline changes along the coast of Sungaibuntu is -0.15 m/yr and -2.89 m/yr along Cemarajaya. The periodic phenomena that affect shoreline changes consist of tidal range with a mean value of 0.796 m, significant wave height (Hs) of 0 - 2.9 m with the dominant direction heading to the southeast, and also sea level rise (SLR). Besides, there is an anthropogenic factor of land use and land cover changes as the significant feature shown by the managed system of ponds, cropland, farmland, paddy field, along with the settlement. As for the instrument development of economic and sanitation vulnerability on fishermen community, it is important to take shoreline changes rate and its causes into account and consider it as vulnerability criteria.

scholarly journals Monitoring of Surface Temperature on Parco delle Biancane (Italian Geothermal Area) Using Optical Satellite Data, UAV and Field Campaigns

2020 ◽  
Vol 12 (12) ◽  
pp. 2018
Author(s):  
Malvina Silvestri ◽  
Enrica Marotta ◽  
Maria Fabrizia Buongiorno ◽  
Gala Avvisati ◽  
Pasquale Belviso ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Spatial Resolution ◽  
Satellite Data ◽  
Field Measurements ◽  
Geothermal Field ◽  
Landsat 8 ◽  
Ground Field ◽  
Thermal Images ◽  
Field Campaigns ◽  
Temperature Maps

The purpose of this study is to analyze the surface temperature and the distribution of thermal signatures on Tuscany’s geothermal districts using data obtained through three separate surveys via satellite and an unmanned aerial vehicle (UAV). The analysis considers the highest available spatial resolution ranging from hundreds of meters per pixel of the satellite thermal images and the tenths/hundreds of centimeters per pixel of the thermal images acquired by the UAV. The surface temperature maps obtained by satellite data acquired at suitable spatial resolution and the thermal measurements obtained by the thermal camera installed on the UAV were orthorectified and geocoded. This allowed, for example, following the evolution of thermal anomalies, which may represent a modification of the current state of the geothermal field and a possible hazard for both the population and industrial assets. Here, we show the results obtained in three field campaigns during which the simultaneous acquisition of Landsat 8 satellite and UAV (FlyBit octocopter, IDS, Rome, Italy) thermal data were analyzed. By removing the atmosphere contribution from Landsat 8 data, we have produced three surface temperature maps that are compared with the ground field measurements and the surface temperature maps elaborated by FLIR VUE PRO-R on the UAV.

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