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Abstrak :
Eksplorasi panas bumi merupakan tahapan yang sangat penting pada kegiatan pengusahaan panas bumi karena memiliki tingkat resiko kegagalan pemboran yang sangat tinggi serta biaya yang dikeluarkan cukup besar. Oleh karena itu, diperlukan interpretasi terpadu berdasarkan data geosains untuk mendelineasi prospek sistem geothermal Gn. Lawu sehingga penentuan lokasi pemboran mempunyai tingkat kepastian yang lebih tinggi. Dalam mendelineasi sistem geothermal sangat ditentukan dengan sebaran batuan resistivitas rendah yang mengindikasikan adanya lapisan penudung (caprock) yang didominasi oleh material lempung. Selain itu, target utama dari eksplorasi panas bumi adalah temperatur dan permeabilitas batuan yang tinggi. Distribusi sebaran temperatur bawah permukaan dapat diperkirakan melalui data manifestasi pada lokasi penelitian. Sedangkan permeabilitas tinggi berasosiasi dengan zona patahan dimana fluida dapat mengalir ke permukaan. Magnetotelluric (MT) merupakan metode geofisika pasif yang melibatkan pengukuran fluktuasi medan listrik dan magnet alam sebagai sarana untuk menentukan resistivitas batuan di bawah permukaan bumi dimana pemodelan data MT dapat dilakukan menggunakan inversi 3D. Untuk memahami lebih lanjut mengenai pemodelan MT tersebut, maka penelitian ini difokuskan pada inversi 3D dengan MT3Dinv-X yang kemudian diintegrasikan dengan data dukung gravitasi, geologi dan geokimia untuk mendelineasi sistem geothermal Gn. Lawu. Hasil akhir penelitian ini adalah memberikan rekomendasi pola sebaran resistivitas batuan serta membuat model konseptual untuk menentukan area target pemboran pada daerah penelitian. ...... Geothermal exploration is crucial step in geothermal business because it has uncertainty drilling result and high cost. Therefore, an integrated interpretation based on geosciences data is needed to delineate the prospect of Gn. Lawu geothermal system so the location of drilling could be more convince. The distribution of low resistivity rocks that indicating the presence of a caprock which is dominated by the material of clay. Moreover, the main target of geothermal exploration is the high temperature and permeability of rocks. The distribution of subsurface temperature can be estimated through the manifestation data on site. High permeability is associated with a fault zone where fluid can flow to the surface. Magnetotelluric (MT) is a passive geophysical method that involves measuring the fluctuations of electric and natural magnetic fields as a means of determining the resistivity of rocks beneath the Earth's surface where MT data modeling can be performed using 3D inversion. To understand more about the MT modeling, this research is focused on 3D inversion with MT3Dinv-X which is then integrated with gravity, geological and geochemical support data to delineate Gn. Lawu geothermal system. The final result of this research is to recommend the pattern of distribution of rock resistivity as well as to create conceptual model to determine drilling target area in research area.

Abstrak :
Area prospek panasbumi Lili, Sulawesi Barat, Indonesia merupakan salah satu daerah prospek yang berasosiasi dengan aktivitas vulkanik yang terjadi sejak zaman Tersier. Aktivitas vulkanik ini diperkirakan merupakan aktivitas gunungapi bawah laut yang berkembang menjadi gunungapi darat berumur Kuarter bawah. Area prospek panasbumi ini memiliki mata air panas tipe klorida, dan tipe bikarbonat yang tersebar di sekitar area prospek. Dari hasil perhitungan geotermometer area prospek panasbumi Lili memiliki temperatur 189-201 °C, yang dikategorikan sebagai moderate to high temperature geothermal system. Untuk mengetahui batas, kedalaman, dan geometri dari reservoir yang ada, dilakukan pengukuran dengan metode Magnetotelluric (MT) serta metode geofisika lainnya sebagai pendukung seperti metode gravitasi, geomagnet, dan geolistrik. Pengukuran dilakukan dengan desain gridding agar dapat diketahui penyebaran resistivitas dari arah Utara-Selatan maupun Barat-Timur. Data MT tersebut dikoreksi terlebih dahulu terhadap efek statik dan noise dengan menggunakan Mat-Lab dan Site to Site Reference sebelum nantinya siap diinterpretasi. Pemodelan sistem panasbumi dari data magnetotellurik dengan menggunakan analisa 2-dimensi dan 3-dimensi. Hasil area prospek berada dari arah barat daya hingga ke tengah lokasi pengukuran menerus ke utara. Rekomendasi pengeboran di sekitar daerah outflow dengan kedalaman sekitar 1.8 km dekat dengan zona patahan yang mempunyai permeabilitas yang lebih besar untuk mendapatkan fluida panasnya. ......Geothermal prospect area in Lili, West Celebes, Indonesia is one of the prospect area in Indonesia associated by volcanic activity which happened since tertiary. This volcanic activity is predicted as undersea volcano which grown become to volcano quartenary. This geothermal prospect area has chloride and bicarbonate hot springs. Based on geothermometry calculation the geothermal prospect area of Lili has temperature 189-201 °C which is categorized as a moderate to high temperature geothermal system. To estimate the boundary, depth, and geometry of the reservoir, Magnetotelluric (MT) and other geophysics methods were used such as gravity, geomagnetic, and geoelectric method as supporting data. Data acquisition was designed gridding method to delineated resistivity distribution in North-South or West-East orientation. MT data was then corrected for static effect and possible noise using Mat-lab and Site to site reference before comprehensive interpretation. Modeling of the geothermal system was carried out by using 2-dimensional MT resistivity and 3-dimensional visualization. As a result, the prospect area is exist in south west until center of measurement area. Pattern of this zone still continue to the north of measurement area. In addition, drilling recommendation is proposed around the outflow in Lili with depth at 1.8 km near the fault zone to get the hot fluid.

Abstrak :
[ABSTRAK
Sistem panas bumi vulkanik, bertemperatur tinggi dan liquid dominated Dieng memiliki potensi sebesar 355 MWe meliputi area Sileri, Sikidang-Merdada dan Pakuwaja. Hingga saat ini telah beroperasi pembangkit listrik berkapasitas 1x60 MW disuplai oleh uap dari sumur di area Sileri.

Re-evaluasi strategi pengembangan lapangan panas bumi Dieng secara terpadu dilakukan dengan mengkaji data geologi, data geokimia manifestasi dan sumur dan data geofisika. Kajian geokimia meliputi air, gas, isotop untuk mengetahui karakteristik kimia reservoir, didukung oleh model 2D Magnetotellurik (MT) yang menggambarkan distribusi resistivitas bawah permukaan, model 2D gravitasi yang menggambarkan struktur bawah permukaan, serta didukung oleh struktur geologi, vulkanostratigrafi dan alterasi hidrothermal.

Hasil penelitian menunjukkan bahwa terdapat dua zona upflow utama di Sileri dan Sikidang. Zona asam di Sikidang ditunjukkan oleh keberadaan fluida magmatik, isotop 18O yang enrich dan mendekati zona andesitic water di sekitar sumur DNG-2 dan DNG-8. Zona aman silica scaling di area Sileri berada di sekitar sumur HCE-31 dan DNG-10.

Pengembangan lapangan Dieng selanjutnya masih mungkin dilakukan di area bagian timur laut yang ditunjukkan oleh keberadaan claycap dan heat source pada zona upflow Sileri.

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ABSTRACT
Volcanic geothermal systems, high temperature and liquid dominated Dieng has a potential of 355 MWe covers an area Sileri, Sikidang-Merdada and Pakuwaja. Until currently operates power plants with a capacity of 1x60 MW supplied by steam from wells in Sileri area.

Re-evaluation of Dieng development strategy in integrated to seek the extension of field development by assessing the geochemical data of manifestations and wells, geophysical data and geological data. Geochemical studies include water, gas and isotope to describe reservoir chemical characteristic, supported by a 2D model of Magnetotelluric (MT) which describes the distribution of subsurface resistivity, 2D model of Gravity depicting subsurface structures, and supported by geological structure, vulkanostratigrafy and hydrothermal alteration.

There are two main upflow zone in Sileri and Sikidang. Acid zone shown at magmatic fluid existence, enrich of 18O and approximate the andesitic water zone in around DNG-2 and DNG-8. Safe Zone of Silica Scaling be in around of HCE-31 and DNG-10.

Furthermore, Dieng development is possible in north-east area which show in clay cap and heat source existence in Sileri Upflow Zone.;Volcanic geothermal systems, high temperature and liquid dominated Dieng has a potential of 355 MWe covers an area Sileri, Sikidang-Merdada and Pakuwaja. Until currently operates power plants with a capacity of 1x60 MW supplied by steam from wells in Sileri area. Re-evaluation of Dieng development strategy in integrated to seek the extension of field development by assessing the geochemical data of manifestations and wells, geophysical data and geological data. Geochemical studies include water, gas and isotope to describe reservoir chemical characteristic, supported by a 2D model of Magnetotelluric (MT) which describes the distribution of subsurface resistivity, 2D model of Gravity depicting subsurface structures, and supported by geological structure, vulkanostratigrafy and hydrothermal alteration. There are two main upflow zone in Sileri and Sikidang. Acid zone shown at magmatic fluid existence, enrich of 18O and approximate the andesitic water zone in around DNG-2 and DNG-8. Safe Zone of Silica Scaling be in around of HCE-31 and DNG-10. Furthermore, Dieng development is possible in north-east area which show in clay cap and heat source existence in Sileri Upflow Zone.;Volcanic geothermal systems, high temperature and liquid dominated Dieng has a potential of 355 MWe covers an area Sileri, Sikidang-Merdada and Pakuwaja. Until currently operates power plants with a capacity of 1x60 MW supplied by steam from wells in Sileri area. Re-evaluation of Dieng development strategy in integrated to seek the extension of field development by assessing the geochemical data of manifestations and wells, geophysical data and geological data. Geochemical studies include water, gas and isotope to describe reservoir chemical characteristic, supported by a 2D model of Magnetotelluric (MT) which describes the distribution of subsurface resistivity, 2D model of Gravity depicting subsurface structures, and supported by geological structure, vulkanostratigrafy and hydrothermal alteration. There are two main upflow zone in Sileri and Sikidang. Acid zone shown at magmatic fluid existence, enrich of 18O and approximate the andesitic water zone in around DNG-2 and DNG-8. Safe Zone of Silica Scaling be in around of HCE-31 and DNG-10. Furthermore, Dieng development is possible in north-east area which show in clay cap and heat source existence in Sileri Upflow Zone., Volcanic geothermal systems, high temperature and liquid dominated Dieng has a potential of 355 MWe covers an area Sileri, Sikidang-Merdada and Pakuwaja. Until currently operates power plants with a capacity of 1x60 MW supplied by steam from wells in Sileri area. Re-evaluation of Dieng development strategy in integrated to seek the extension of field development by assessing the geochemical data of manifestations and wells, geophysical data and geological data. Geochemical studies include water, gas and isotope to describe reservoir chemical characteristic, supported by a 2D model of Magnetotelluric (MT) which describes the distribution of subsurface resistivity, 2D model of Gravity depicting subsurface structures, and supported by geological structure, vulkanostratigrafy and hydrothermal alteration. There are two main upflow zone in Sileri and Sikidang. Acid zone shown at magmatic fluid existence, enrich of 18O and approximate the andesitic water zone in around DNG-2 and DNG-8. Safe Zone of Silica Scaling be in around of HCE-31 and DNG-10. Furthermore, Dieng development is possible in north-east area which show in clay cap and heat source existence in Sileri Upflow Zone.]

Abstrak :
Pengembangan panasbumi memiliki resiko kegagalan yang tinggi bagi para investor. Oleh karena itu, tahap eksplorasi mempunyai peran penting dalam pengembangan panasbumi. Dalam tahap eksplorasi diperlukan pemahaman yang baik mengenai kondisi bawah-permukaan dengan mengintegrasikan data geosains. Daerah panas bumi Cisolok-Cisukarame berada di lingkungan batuan sedimen berumur Miosen-Pliosen, batuan intrusi asam Miosen-Pliosen dan batuan andesit Plistosen. Batuan berumur Plistosen ini merupakan produk vulkanik termuda di daerah ini. Berdasarkan pemunculan manifestasi panas dipermukaan, didentifikasikan tiga zona prospek panas bumi yaitu prospek panas bumi Cisolok, Cisukarame dan Sangiang. Di daerah ini terdapat 3 kelompok mata air panas yaitu kelompok Cisolok, Cisukarame, dan Cimagit. Manifestasi panas yang muncul di Cisolok Cisukarame terdiri dari mata air panas, endapan sinter dan batuan teralterasi. Kemunculan batuan teralterasi diperkirakan dikontrol oleh struktur berarah timur laut-barat daya dan barat laut-tenggara. Analisis Prospek Panasbumi Cisolok Cisukarame Menggunakan Data Magnetotelluric dan Gravitasi dilakukan untuk mengkaji data geokimia dan data geologi sebagai data pendukung serta data geofisika yaitu data Magnetotelluric dan Gravitasi sebagai data utama. Dari kajian geokimia dapat diketahui bahwa area geothermal Cisolok Cisukarame merupakan sistem dengan dominasi air dengan temperatur reservoir pada area prospek Cisolok berada pada kisaran 140 - 150 oC sedangkan pada area prospek Cisukarame berada pada kisaran 170 - 190 oC. Dari pemodelan 2D Magnetotellurik (MT) yang menggambarkan distribusi resistivitas bawah permukaan diketahui bahwa zona prospek panasbumi yang layak untuk dikembangkan adalah di area Cisukarame. Hal tersebut juga didukung model 2D gravitasi yang menggambarkan struktur bawah permukaan. Dari data geosains didapatkan model konseptual serta rekomendasi target pemboran yaitu Sumur A1 diarahkan memotong struktur yang berarah timur laut - barat daya dengan kedalaman sumur ±1200 m. Sedangkan sumur A2 diarahkan memotong struktur yang berarah tenggara - barat laut dengan kedalaman sumur ±1200 m. Sumur B di tempatkan mengarah pada struktur yang mengontrol pemunculan manifestasi mata air panas yaitu memotong struktur yang berarah timur laut ? barat daya dan struktur yang berarah utara - selatan, dengan kedalaman sumur sekitar ±1200 meter. Estimasi total potensi energi panas bumi untuk area prospek Cisukarame dengan menggunakan binary cycle power plant adalah sebesar 18 MWe hingga 39,6 MWe.

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Geothermal development has a high risk of failure for investors. Therefore, the exploration phase has an important role in the development of geothermal. The exploration phase required a good understanding of subsurface conditions by integrating the data geosciences. Geothermal area Cisolok - Cisukarame located within sedimentary rocks Miocene - Pliocene , Miocene - acid intrusive rocks of Pliocene and Pleistocene andesite. Rock Pleistocene age is the youngest volcanic products in this area. Based on the appearance of the surface manifestations, is identified three zones geothermal prospects Cisolok , Cisukarame and Sangiang. In this area there are 3 groups of hot springs that group Cisolok, Cisukarame, and Cimagit. Heat manifestations that appear in Cisolok Cisukarame consists of hot springs, sediment and rock alteration sinter. The emergence of rock alteration estimated controlled by trending structures northeast - southwest and northwest - southeast. Geothermal Prospects Analysis Cisolok Cisukarame Using Data Magnetotelluric and Gravity conducted to assess the geochemical data and geological data as supporting data and geophysical data is data Magnetotelluric and Gravity as the main data. From the geochemical studies it is known that the geothermal area Cisolok Cisukarame is a system of domination by the temperature of water in the reservoir area Cisolok prospects in the range of 140-150 ° C while the Cisukarame prospect area in the range of 170-190 ° C. From modeling 2D magnetotelluric (MT) which describes the subsurface resistivity distribution is known that the possible zone geothermal prospects for development is in the Cisukarame area. This is also supported by 2D gravity models which describe the subsurface structure. From the data geoscience obtained conceptual model and well drilling targets recommendations are well A1 directed to northeast - southwest trending structures with a well depth of 1200 m ± . While wells A2 directed to southeast - northwest trending structures at a depth of 1200 m ± wells . Wells B in place leads to structures that control the appearance of the manifestation of the hot springs are cut structures trending northeast - southwest and structures trending north - south, with a well depth of about ± 1200 meters . Estimates of the total potential of geothermal energy for Cisukarame prospect area by using binary cycle power plant is 18 MWe to 39.6 MWe.

Abstrak :
[ABSTRAK
Telah diakukan penelitian guna mendelineasi zona prospek sistem panasbumi Daerah „P‟ menggunakan pemodelan multi dimensi data magnetotelurik terintegrasi data geologi dan geokimia. Daerah panasbumi „P‟ secara fisiografi termasuk pada Busur Banda Dalam tak bergunungapi disusun oleh komplek batuan malihan sekis berumur Perm-Trias. Gejala adanya sistem panasbumi pada daerah penelitian ditandai dengan kemunculan manifestasi permukaan berupa enam mata air panas bersuhu (37-67oC), pH (6-7) dan bertipe klorida-bikarbonat. Pembentukan sistem panasbumi diduga berkaitan dengan aktivitas tektonik kuat akibat tumbukan lempeng Pulau Seram dengan Lempeng Benua Australia (Plate Collision) yang memicu pembentukan batuan intrusi di kedalaman sebagai sumber panas. Guna mengetahui informasi subsurface daerah penelitian, dilakukan survei magnetotelurik. Selanjutnya hasil dari data MT akan diintegrasikan data geologi dan geokimia. Pengolahan data MT dimulai dari time-series data hingga mendapatkan kurva resistivitas-frekuensi dan fase, lalu dilakukan filtering noise, rotasi arah strike dan koreksi static shift untuk mendapatkan kualitas kurva MT baik. Selanjutnya dilakukan pemodelan inversi 1D, 2D dan 3D. Temperatur reservoir diduga sekitar 160-180oC termasuk temperatur sedang. Hasil penelitian ini memperlihatkan lapisan konduktif (<15 Ωm) dengan ketebalan ± 500-1000 m diindikasikan sebagai Clay Cap dari sistem panasbumi. Zona resistivitas tinggi (>300 Ωm) dan berbentuk updome, berada di bawah area kemunculan manifestasi (MAP1, MAP2, MAP3, MAP4, dan MAP5) mengindikasikan heat source berada di utara kemudian menerus ke arah tenggara membentuk updome. Model konseptual terpadu sistem panasbumi dibentuk dari integrasi data geologi, geokimia, dan geofisika. Sistem panasbumi daerah penelitian merupakan hidrotermal heat sweep plate collision dengan temperatur sedang, luas area prospek dan rekomendasi titik pemboran diperkirakan ± 3 km2 di sekitar zona Upflow, potensi sumber daya hipotetik dengan metode volume lump parameter menggunakan binary cycle ± 34 MWe.

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ABSTRACT
A study for delineating geothermal system of prospect area “P” has been done by using multi-dimensional modeling of magnetotelluric data. Physiographycally, geothermal prospect of “P” area is located at non-volcanic Banda inner arc hosted by Malihan Sekis rock complex with Perm-Trias age. The existance of geothermal system in this area is indicated by the presence of thermal manifestations in form of 6 chloride-bicarbonate hot springs with temperature in the the range of 37 – 67oC, and pH of 6-7. The development of geothermal system is most probably associated with strong tectonic activity caused by the collision between Seram island plate and Australian plate that ignite the occurence of intrussive body as heat source. In order to know the subsurface information of prospect area, magnetotelluric (MT) survey has been done. The processing of MT data was started from time-series data, continued by noise filtering, rotation of strike orientation and static shift correction to obtain better MT curve. The data were then being inversed by means of 1-Dimensional, 2-Dimensional and 3-Dimensional inversion methods. Reservoir temperature is estimated to be around 160-180 oC and classified as moderate temperature. The result of MT data inversions shows the presence of conductive layer (<15 Ωm) with 500 – 1000 m thickness that is interpreted as clay cap og geothermal system. High resistivity zone (>300 Ωm) with updome shape appears underneath the manifestations occurence (MAP1, MAP2, MAP4, and MAP5), indicating that the heat source is located in northern part and elongate to souteast direction. The conceptual model of geothermal system was built based on integrated interpretation of geological, geochemical and geophysical data. The prospect area and recommendation of drilling location is estimated to be ± 5 km2 around upflow zone. Potential hypothetical resource with volume lump parameters method using binary cycle ± 34 MWe., A study for delineating geothermal system of prospect area “P” has been done by using multi-dimensional modeling of magnetotelluric data. Physiographycally, geothermal prospect of “P” area is located at non-volcanic Banda inner arc hosted by Malihan Sekis rock complex with Perm-Trias age. The existance of geothermal system in this area is indicated by the presence of thermal manifestations in form of 6 chloride-bicarbonate hot springs with temperature in the the range of 37 – 67oC, and pH of 6-7. The development of geothermal system is most probably associated with strong tectonic activity caused by the collision between Seram island plate and Australian plate that ignite the occurence of intrussive body as heat source. In order to know the subsurface information of prospect area, magnetotelluric (MT) survey has been done. The processing of MT data was started from time-series data, continued by noise filtering, rotation of strike orientation and static shift correction to obtain better MT curve. The data were then being inversed by means of 1-Dimensional, 2-Dimensional and 3-Dimensional inversion methods. Reservoir temperature is estimated to be around 160-180 oC and classified as moderate temperature. The result of MT data inversions shows the presence of conductive layer (<15 Ωm) with 500 – 1000 m thickness that is interpreted as clay cap og geothermal system. High resistivity zone (>300 Ωm) with updome shape appears underneath the manifestations occurence (MAP1, MAP2, MAP4, and MAP5), indicating that the heat source is located in northern part and elongate to souteast direction. The conceptual model of geothermal system was built based on integrated interpretation of geological, geochemical and geophysical data. The prospect area and recommendation of drilling location is estimated to be ± 5 km2 around upflow zone. Potential hypothetical resource with volume lump parameters method using binary cycle ± 34 MWe.]

Abstrak :
Daerah penelitian berada pada area dengan setting geologi vulkanik (gunungapi) yang berkembang pada tepi suatu sistem sesar besar (major) dimana panas bumi yang berkembang di daerah ini dipengaruhi oleh aktivitas vulkanime dan struktur geologi yang dominan berupa sistem struktur-struktur besar berarah barat laut-tenggara yang membentuk depresi graben di bagian tengahnya. Batuan tertua yang merupakan batuan dasar di daerah ini adalah batuan metamorf berumur tersier dan di atasnya terendapkan beberapa satuan batuan produk vulkanik yang terbentuk dari aktivitas vulkanik kuarter. Manifestasi panas bumi yang ditemui berupa fumarol (temperatur 70-95oC) dan mata air panas sulfat yang berada pada topografi tinggi (sekitar puncak gunung X) dan beberapa mata air panas bikarbonat (temperatur 34 - 56oC) yang memiliki sebaran searah dengan pola struktur. Struktur geologi diidentifikasi kemenerusannya di bawah permukaan dengan metode geofisika yang terdiri dari gravity (First Horizontal Derivative, Second Vertical Derivative, forward model 2-D) dan MT (splitting curve dan inversi 3-D) sehingga dapat dianalisis zona permeabel yang berasosiasi dengan fracture dan patahan sebagai permeabilitas sekunder yang terisi oleh fluida panas bumi. Zona permeabel diduga berada pada area graben yang dibatasi/dikontrol oleh sesar utama di bagian barat dan timurnya dan diperkirakan menerus ke selatan pada area sekitar puncak Gunung Tg yaitu pada kompleks manifestasi fumarol. Hal ini didukung oleh data hasil inversi MT yang menunjukkan korelasi sebaran lapisan konduktif dengan zona yang diduga sebagai zona permeabel tersebut. Berdasarkan konseptual model, area prospek panas bumi yang direkomendasikan sebagai zona pemboran diperkirakan berada pada zona upflow yang berada di sekitar area puncak Gunung Tg yaitu di area kompleks manifestasi fumarol.

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The research area is located in a volcanic geological setting that arise on the edge of a major fault system. Geothermal system is influenced by volcanic activity and northwest-southeast trending major structures that form the depression/graben. The oldest rock as basement in this area is tertiary metamorphic rocks and overlying of it, deposited several units of rock as products of quarternary volcanic activity. Geothermal manifestations found as fumaroles (temperature 70-95oC) and sulfate hot springs located at high topography, and several bicarbonate hot springs (temperature 34 - 56oC) that scattered at same direction with trend of structures. The geological structures are identified below the surface by gravity (First Horizontal Derivative, Second Vertical Derivative, 2-D forward model) and MT (splitting curve and 3-D inversion), then the permeable zone that associated with fracture and fault can be analyzed. The permeable zone thought to be in the graben area and estimated to be extend southward to the area around the peak of Mount Tg. This is supported by MT inversion data which shows correlation of conductive layer distribution with permeable zone. Based on the conceptual model, the geothermal prospect area that recommended as the drilling zone is estimated to be in the upflow zone around the peak of Mount Tg in the area of the fumarole manifestation.

Abstrak :
ABSTRAK Energi panas bumi merupakan energi terbarukan yang sedang berkembang di dunia modern. Untuk memanfaatkan energi panas bumi, butuh dilakukan eksplorasi terlebih dahulu untuk menentukan daerah dengan prospek system geothermal. Setelah dilakukan perkiraan dasar wilayah prospek melalui data geologi dan geokimia di permukaan bumi, dilakukan survey geofisika untuk melihat keadaan dibawah permukaan. Salah satu metode yang dapat digunakan adalah metode Micro Earthquake (MEQ). Metode Micro Earthquake dapat digunakan untuk memperkirakan arah patahan dan rekahan yang ada dibawah permukaan. Celah pada patahan yang kadang saling bergesekan menyebabkan gempa-gempa mikro di sepanjang patahan. Dengan mengikuti persebaran hiposenter gempa mikro yang didapat, struktur patahan pada daerah penelitian dapat diperkirakan. Persebaran hiposenter akan dicari dengan menggunakan software Hypo71 dan kemudian direlokasi dengan software HypoDD agar hiposenter yang didapat lebih akurat. Hasil dari relokasi akan divisualisasikan agar data lebih mudah dinterpretasikan. Dari hasil struktur patahan yang didapat, daerah prospek geothermal yang merupakan daerah perkiraan reservoir dari system geothermal.

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ABSTRACT Energi panas bumi merupakan energi terbarukan yang sedang berkembang di dunia modern. Untuk memanfaatkan energi panas bumi, butuh dilakukan eksplorasi terlebih dahulu untuk menentukan daerah dengan prospek system geothermal. Setelah dilakukan perkiraan dasar wilayah prospek melalui data geologi dan geokimia di permukaan bumi, dilakukan survey geofisika untuk melihat keadaan dibawah permukaan. Salah satu metode yang dapat digunakan adalah metode Micro Earthquake (MEQ). Metode Micro Earthquake dapat digunakan untuk memperkirakan arah patahan dan rekahan yang ada dibawah permukaan. Celah pada patahan yang kadang saling bergesekan menyebabkan gempa-gempa mikro di sepanjang patahan. Dengan mengikuti persebaran hiposenter gempa mikro yang didapat, struktur patahan pada daerah penelitian dapat diperkirakan. Persebaran hiposenter akan dicari dengan menggunakan software Hypo71 dan kemudian direlokasi dengan software HypoDD agar hiposenter yang didapat lebih akurat. Hasil dari relokasi akan divisualisasikan agar data lebih mudah dinterpretasikan. Dari hasil struktur patahan yang didapat, daerah prospek geothermal yang merupakan daerah perkiraan reservoir dari system geothermal.

Abstrak :
A study at several geothermal systems in West Java,Indonesia shows that thermal waters could naturally contain up to 2.6 ppm As and 6.5 ppb Hg,and the survace hydrothermal alteration could contribute up to 50 ppm As and 800 ppb Hg....

Abstrak :
Thermal waters at Ciarrinem and Cilayu,Pameungpeuk, West Java, Indonesia have different characteristics: Cairinem water is a steam heated sulfate type and accurs as hot springs,whereas Cilayu water discharges as hot pools and is a chloride water type......