Siombone, Salman Hamja (2019) Identifikasi Reservoar Panas Bumi Di Desa Tiris Kompleks Gunungapi Lamongan Kabupaten Probolinggo, Jawa Timur Dengan Menggunakan Metode Gravitasi Dan Penginderaan Jauh. Magister thesis, Universitas Brawijaya.
Abstract
Desa Tiris, kompleks Gunungapi Lamongan merupakan daerah yang memiliki potensi panas bumi. Keberadaan potensi panas bumi tersebut dalam penelitian ini diidentifikasikan dengan menggunakan metode gravitasi yang dikombinasikan dengan metode penginderaan jauh. Metode penginderaan jauh digunakan untuk memperoleh peta pola sebaran suhu permukaan tanah dan peta bentuk kemenerusan struktur kelurusan dan patahan. Data yang digunakan dalam metode penginderaan jauh adalah data sekunder berupa data citra Landsat-8 dan DEM SRTM 1arc. Pengolahan peta suhu permukaan tanah diperoleh dengan menggunakan citra thermal infrared dengan bantuan metode semi empiris berdasarkan data hasil pengolahan NDVI. Bentuk kemenerusan struktur kelurusan atau patahan diperoleh dengan mengolah data citra multispektral Landsat-8 berupa komposit band 567 dan data DEM SRTM berupa pemodelan topografi 3D. Data hasil komposit band 567 tersebut dikaji ulang secara visual menggukan model topografi 3D. Metode gravitasi merupakan metode utama dalam penelitian ini karena digunakan untuk mendapatkan sebaran anomali Bouguer residual. Data anomali Bouguer residual diperoleh dengan menggunakan metode moving average melalui analisis spektrum. Sebaran anomali Bouguer residual dapat digunakan untuk interpretasi kualitatif terhadap sebaran percepatan gravitasi bumi di lokasi pengukuran. Interpretasi kuantitatif data gravitasi didasarkan pada grafik estimasi densitas permukaan menggunakan metode Parasnis dan pemodelan inversi 3D, menggunakan data anomali Bouguer residual. Berdasarkan metode Parasnis, diperoleh densitas rata-rata batuan di lokasi pengukuran adalah 2,72 g/cm3, yang menunjukkan bahwa batuan penyusun bawah permukaan pada lokasi pengukuran tersusun atas batuan beku vulkanik. Hasil pemodelan inversi 3D memberikan empat jenis lapisan batuan penyusun bawah permukaan berdasarkan nilai sebaran densitas, yaitu lapisan batuan pertama = 2,52 – 2,67 g/cm3, lapisan batuan kedua = 2,72 – 2,77 g/cm3, lapisan batuan ketiga = 2,80 – 2,83 g/cm3, dan lapisan batuan keempat = 2,84 – 2,86 g/cm3. Lapisan batuan ketiga diduga sebagai batuan reservoar dan diperkirakan berada pada kedalaman 500 – 800 meter di bawah titik pengukuran. Lapisan batuan keempat diduga sebagai batuan beku intrusi, yang menerobos dominan pada tengah-tengah lokasi pengukuran, yang berorientasi baratdaya, selatan menuju utara, yang ditunjukkan oleh kemenerusan anomali tinggi pada peta anomali Bouguer regional. Berdasarkan hasil pemodelan inversi 3D dan analisis spektrum terhadap kedalaman rata-rata anomali Bouguer regional, diperoleh bahwa lapisan batuan intrusi diduga berada pada kedalaman 350 meter di bawah titik pengukuran.
English Abstract
Village of Tiris, Lamongan Volcano Complex, is an area that has geothermal potential. In this research, the existence of geothermal potential was identified by using the gravity method combined with the remote sensing method. The later method was applied to map land surface temperature distribution, lineaments, and faults. Data used were secondary ones in forms of Landsat-8 images and DEM SRTM 1arc. Map of land surface temperature was obtained by processing thermal infrared images with the help of the semi-empirical method according to the data of NDVI processing output. Lineament and fault structures were obtained by processing the multispectral Landsat-8 images data, i.e. 567 band composites and DEM SRTM data in forms of topographic 3D modeling. The data were visually re-studied by employing the topographic 3D model. Meanwhile, the gravity method was the main method used in this research to obtain Bouguer residual anomaly distribution. Data for the distribution were obtained by applying the moving average method through the spectrum analysis. The distribution was usable to qualitatively interpret the distribution of Earth gravitation acceleration at the measurement locations. Quantitative interpretation for gravitation data was based on the graphic of surface density estimation using Parasnis method, and 3D inversion modeling using Bouguer residual anomaly data. In accordance with Parasnis method, the mean rock density value at the measurement location was 2.72 g/cm3, clarifying that the subsurface composing rocks at the measurement location are a volcanic igneous rock. Moreover, according to the 3D inversion modeling results, there were four types of subsurface rock constituent layers based on the density distribution values, namely the first rock layer = 2.52 – 2.67 g/cm3, second rock layer = 2.72 – 2.77 g/cm3, third rock layer = 2.80 – 2.83 g/cm3, and fourth rock layer = 2.84 – 2.86 g/cm3. The third rock layer was considered as reservoir rocks and predicted to exist in the depth of 500-800 meters under the measurement location. Meanwhile, the fourth rock layer was considered to be intrusion igneous rock, that passed through the center of measurement location oriented to the southwest, the south to the north, which is indicated by the high anomaly continuity on the regional Bouguer anomaly map. Based on the results of 3D inversion modeling and spectrum analysis on the average depth of regional Bouguer anomalies, it was obtained that the intrusion igneous rock layer was considered to be at a depth of ± 350 meters below the measurement point.
Other obstract
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| Item Type: | Thesis (Magister) |
|---|---|
| Identification Number: | TES/621.44/SIO/i/2019/041903793 |
| Uncontrolled Keywords: | GEOTHERMAL RESOURCES |
| Subjects: | 600 Technology (Applied sciences) > 621 Applied physics > 621.4 Prime movers and heat engineering > 621.44 Geothermal engineering |
| Divisions: | S2/S3 > Magister Fisika, Fakultas MIPA |
| Depositing User: | Endang Susworini |
| Date Deposited: | 12 Mar 2020 04:17 |
| Last Modified: | 12 Mar 2020 04:17 |
| URI: | http://repository.ub.ac.id/id/eprint/180333 |
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