Pemodelan Inversi 1D dan 2D Data Magnetotelurik dengan Mode Polarisasi TE, TM, TETM di Wilayah Prospek Panasbumi Bonjol, Pasaman, Sumatera Barat

Bagaskara, Franciscus Xaverius Gagah Wiku (2024) Pemodelan Inversi 1D dan 2D Data Magnetotelurik dengan Mode Polarisasi TE, TM, TETM di Wilayah Prospek Panasbumi Bonjol, Pasaman, Sumatera Barat. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Metode magnetotellurik (MT) adalah salah satu metode geofisika, dan tergolong metode elektromagnetik pasif (EM) yang mengukur medan listrik (E) dan medan magnet (B) dalam arah ortogonal di permukaan bumi. Metode ini bertujuan untuk mengetahui persebaran nilai resistivitas batuan di bawah permukaan, dengan penetrasi kedalaman dari puluhan hingga ribuan meter. Parameter yang diukur dari metode ini adalah gelombang elektromagnetik alami, yaitu medan listrik bumi (komponen Ex dan Ey) serta medan magnet bumi (komponen Hx, Hy, dan Hz. Dilakukan pemodelan inversi 1-dimensi serta pemodelan inversi 2-dimensi untuk mendapatkan hasil pemodelan bawah permukaan melalui persebaran nilai resistivitas. Dalam proses pengolahan data magnetotelurik, terdapat pemisahan mode polarisasi yaitu mode TE (Tranverse Electric), mode TM (Transverse Magnetic) dan mode TE-TM. Mode polarisasi tersebut digunakan untuk meningkatkan kualitas data MT dalam mencitrakan bawah permukaan. Penelitian ini bertujuan untuk menentukan hasil pemodelan inversi 1D dan 2D magnetotelurik pada wilayah prospek panasbumi Bonjol, serta mendapatkan hasil analisis perbedaan mode polarisasi TE, TM, dan TETM pada pemodelan inversi data magnetotelurik 2D. Dalam hasil inversi 1D, didapatkan hasil inversi Occam lebih baik daripada hasil inversi Bostick. Sedangkan dalam hasil inversi 2D, hasil dengan mode TETM merupakan mode polarisasi yang paling sesuai dengan kondisi geologi dibandingkan dengan mode polarisasi TE dan TM. Terdapat 3 unsur penting dalam sistem panas bumi, yaitu caprock dengan rentang nilai resistivitas rendah di bawah 60 ohm.m, zona reservoir dengan rentang nilai resistivitas sedang 60-600 ohm.m, dan heat source dengan rentang nilai resistivitas tinggi di atas 600 ohm.m Adapun struktur geologi yang berperan penting dalam sistem panasbumi Bonjol, yaitu sesar Alahanmati, sesar Bonjol, sesar Padangbaru, dan sesar Malintang.
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The magnetotelluric (MT) method is a geophysical method, and is classified as a passive electromagnetic (EM) method which measures the electric field (E) and magnetic field (B) in orthogonal directions on the earth's surface. This method aims to determine the distribution of rock resistivity values below the surface, with penetration depths from tens to thousands of meters. The parameters measured by this method are natural electromagnetic waves, namely the earth's electric field (Ex and Ey components) and the earth's magnetic field (Hx, Hy and Hz components. 1-dimensional inversion modeling and 2-dimensional inversion modeling are carried out to obtain modeling results subsurface through the distribution of resistivity values. In the magnetotelluric data processing process, there is a separation of polarization modes, namely TE (Tranverse Electric) mode, TM (Transverse Magnetic) mode and TE-TM mode. This polarization mode is used to improve the quality of MT data in imaging the subsurface This research aims to determine the results of 1D and 2D magnetotelluric inversion modeling in the Bonjol geothermal prospect area, as well as to obtain analysis results of differences in TE, TM and TETM polarization modes in 2D magnetotelluric data inversion modeling. In the 1D inversion results, the Occam inversion results were better. than the Bostick inversion results. Meanwhile, in the 2D inversion results, the results with the TETM mode are the polarization mode that best suits the geological conditions compared to the TE and TM polarization modes. There are 3 important elements in a geothermal system, namely caprock with a low resistivity value range below 60 ohm.m, reservoir zone with a medium resistivity value range of 60-600 ohm.m, and heat source with a high resistivity value range above 600 ohm. m The geological structures that play an important role in the Bonjol geothermal system are the Alahanmati fault, Bonjol fault, Padangbaru fault and Malintang fault.

Item Type:	Thesis (Other)
Additional Information:	RSGf 538.3 FRA p 2023
Uncontrolled Keywords:	Magnetotelurik, Tranverse Electric, Transverse Magnetic, Inversi 1D, Inversi 2D, Magnetotelluric, 1D Inversion, 2D Inversion
Subjects:	G Geography. Anthropology. Recreation > GB Physical geography > GB1199.5 Geothermal resources
Divisions:	Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Geophysics Engineering > 33201-(S1) Undergraduate Thesis
Depositing User:	Franciscus Xaverius Gagah Wiku Bagaskara
Date Deposited:	06 Feb 2024 04:12
Last Modified:	04 Nov 2024 07:10
URI:	http://repository.its.ac.id/id/eprint/106171

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