Identifikasi Struktur Bawah Permukaan Lapangan Panas Bumi Danau Ranau Berbasis Metode Gaya Berat

Dwiska, Calvin Ashari (2025) Identifikasi Struktur Bawah Permukaan Lapangan Panas Bumi Danau Ranau Berbasis Metode Gaya Berat. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Danau Ranau merupakan salah satu lapangan panas bumi yang menjadi target dalam Rencana Usaha Penyediaan Tenaga Listrik (RUPTL) PLN periode 2021 – 2023. Sehingga dibutuhkan identifikasi terkait struktur bawah permukaan yang mengontrol manifestasi permukaan di lapangan Danau Ranau. Metode yang baik digunakan untuk identifikasi struktur bawah permukaan adalah metode gaya berat. Selain menggunakan data gaya berat, juga digunakan data hidrokimia untuk menganalisis karakteristik fluida manifestasi. Area penelitian berada di perbatasan Sumatera Selatan dan Lampung, dengan potensi panas bumi yang terkait aktivitas Gunung Seminung. Data gaya berat diambil dari 113 titik pengukuran menggunakan gravimeter Lacoste & Romberg, dengan spasi 1 – 2 kilometer. Data hidrokimia diperoleh dari sampel mata air panas tahun 2004. Pengolahan data gaya berat meliputi koreksi lintang, koreksi free air, koreksi bouguer, dan koreksi terrain. Kemudian dilakukan pemisahan anomali regional dan residual, dan filtering First Horizontal Derivative (FHD). Hasil menunjukkan densitas rata-rata 2,59 g/cc, dengan anomali Bouguer total berkisar antara 19.8 hingga 40.2 mGal. Struktur geologi berorientasi NE-SW diperkirakan mengontrol manifestasi pada bagian barat area penelitian.Analisis hidrokimia menunjukkan fluida tipe campuran (mixed water), didominasi oleh ion Na⁺ dan HCO₃⁻, yang mengindikasikan pencampuran fluida reservoir dalam dengan air meteorik kaya HCO₃⁻ akibat pelarutan CO₂. Manifestasi pada bagian barat diidentifikasi sebagai zona upflow dari reservoir. Penelitian lebih lanjut disarankan untuk melakukan pengambilan data hidrokimia terbaru dan pemodelan densitas 2D/3D untuk memperjelas struktur geologi serta mendukung eksplorasi lebih lanjut di wilayah tersebut.
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Danau Ranau is one of the geothermal fields targeted in the PLN’s Electricity Supply Business Plan (RUPTL) for the period 2021–2023. Therefore, identifying the subsurface structures controlling surface manifestations in the Danau Ranau field is essential. The gravity method is an effective approach for identifying subsurface structures. In addition to gravity data, hydrochemical data were also used to analyze the characteristics of manifestation fluids. The research area is located at the border of South Sumatra and Lampung, with geothermal potential associated with the activity of Mount Seminung. Gravity data were collected from 113 measurement points using a Lacoste & Romberg gravimeter, with a spacing of 1–2 kilometers. Hydrochemical data were obtained from hot spring samples collected in 2004. Gravity data processing included latitude correction, free-air correction, Bouguer correction, and terrain correction. Subsequently, regional and residual anomaly separation and First Horizontal Derivative (FHD) filtering were performed. The results revealed an average density of 2.59 g/cm³, with total Bouguer anomalies ranging from 19.8 to 40.2 mGal. Geological structures oriented in a NE-SW direction are estimated to control manifestations in the western part of the research area. Hydrochemical analysis indicates a mixed water fluid type, dominated by Na⁺ and HCO₃⁻ ions, suggesting the mixing of deep reservoir fluids with meteoric water rich in HCO₃⁻ due to CO₂ dissolution. Manifestations in the western part are identified as an upflow zone from the reservoir. Further research is recommended to collect updated hydrochemical data and conduct 2D/3D density modeling to refine the understanding of geological structures and support further exploration in the region.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Danau Ranau, First Horizontal Derivative, Gaya Berat, Hidrokimia, Struktur, Danau Ranau, First Horizontal Derivative, Gravity, Hydrochemical, Structure.
Subjects:	Q Science > QE Geology > QE601 Geology, Structural
Divisions:	Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Geophysics Engineering > 33201-(S1) Undergraduate Thesis
Depositing User:	Calvin Ashari Dwiska
Date Deposited:	05 Aug 2025 01:40
Last Modified:	05 Aug 2025 01:40
URI:	http://repository.its.ac.id/id/eprint/124382

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