Ramadhana, Moch. Dimas (2025) Identifikasi Struktur Geologi Bawah Permukaan Di Daerah Garut Selatan Menggunakan Metode Magnetotellurik. Other thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Wilayah Garut Selatan merupakan zona tektonik aktif dengan potensi besar untuk sumber daya geologi, namun juga memiliki kerentanannya terhadap bencana alam. Metode Magnetotellurik (MT) digunakan untuk mengidentifikasi potensi ini melalui pemodelan resistivitas bawah permukaan. Hasil resistivitas bawah permukaan ini sangat tergantung pada arah geoelectric strike dan analisis dimensionalitasnya. Oleh karena itu, pada penelitian ini rotasi geoelectric strike dan analisis dimensionalitas dilakukan untuk mengatasi ketidakpastian orientasi geoelectric strike dan kompleksitas struktural yang dapat menyebabkan kesalahan interpretasi. Dengan melakukan proses rotasi geoelectric strike dan analisis dimensionalitas, resistivitas bawah permukaan hasil inversi dievaluasi untuk mengidentifikasi struktur geologi bawah permukaan. Analisis geoelectric strike dan dimensionalitas ini diujicobakan pada data MT yang terukur di daerah Garut bagian selatan dengan panjang lintasan 38,05 km. Analisis Z-skew diterapkan untuk pemilihan zona inversi berdasarkan nilai Z-skew < 0,3 yang merpresentasikan karakter data dua dimensi, sedangkan sudut rotasi 67,5° dipilih berdasarkan analisis distribusi arah impedansi dominan serta disesuaikan dengan orientasi sesar terdekat, yaitu Sesar Garsela. Inversi menggunakan metode Non-Linear Conjugate Gradient (NLCG) pada MT menunjukkan penurunan root mean square error (RMSE) dari 2,5206 menjadi 1,9883, serta mengungkapkan tiga lapisan utama yaitu lapisan dangkal yang cukup konduktif, lapisan menengah yang lebih resistif, serta lapisan dalam dengan resistivitas sangat tinggi.
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The South Garut region is an active tectonic zone with significant potential for geological resources, but it is also vulnerable to natural hazards. The Magnetotelluric (MT) method is employed to identify this potential through subsurface resistivity modeling. The resulting subsurface resistivity is highly dependent on the geoelectric strike orientation and dimensionality analysis. Therefore, in this study, geoelectric strike rotation and dimensionality analysis were applied to address uncertainties in strike orientation and structural complexity that may lead to interpretation errors. By performing geoelectric strike rotation and dimensionality analysis, the inverted resistivity model was evaluated to identify subsurface geological structures. This analysis was conducted using MT data measured in the southern part of Garut along a 38.05 km survey line. Z-skew analysis was applied to select inversion zones based on Z-skew values less than 0.3, representing two-dimensional data characteristics, while a rotation angle of 67.5° was selected based on the dominant impedance direction distribution and adjusted to the orientation of the nearest fault, namely the Garsela Fault. The inversion using the Non-Linear Conjugate Gradient (NLCG) method on the MT data resulted in a decrease in root mean square error (RMSE) from 2.5206 to 1.9883 and revealed three major layers: a shallow conductive layer, an intermediate resistive layer, and a deep layer with very high resistivity.
| Item Type: | Thesis (Other) |
|---|---|
| Uncontrolled Keywords: | Geoelectric Strike, Magnetotellurik, Resistivitas, Z-skew, Geoelectric Strike, Magnetotelluric, Resistivity, Z-skew |
| Subjects: | Q Science > QC Physics > QC1 Dielectrics Q Science > QC Physics > QC20.7.F67 Fourier transformations Q Science > QC Physics > QC665.E38 Electric fields. Q Science > QC Physics > QC701 Electric discharges--Measurement. |
| Divisions: | Faculty of Science and Data Analytics (SCIENTICS) > Physics > 45201-(S1) Undergraduate Thesis |
| Depositing User: | Moch. Dimas Ramadhana |
| Date Deposited: | 04 Aug 2025 11:37 |
| Last Modified: | 04 Aug 2025 11:37 |
| URI: | http://repository.its.ac.id/id/eprint/125245 |
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