Integrasi Metode Self-Potential Dan Electrical Resistivity Tomography Untuk Memetakan Aliran Hidrotermal Bawah Permukaan (Studi Kasus: Gunung Api Bromo, Jawa Timur)

Suhada, Diman Iakunu (2026) Integrasi Metode Self-Potential Dan Electrical Resistivity Tomography Untuk Memetakan Aliran Hidrotermal Bawah Permukaan (Studi Kasus: Gunung Api Bromo, Jawa Timur). Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Gunung Bromo merupakan gunung berapi aktif yang memiliki sistem hidrotermal aktif dan berperan dalam proses erupsi yang terjadi. Zona hidrogeologi dangkal telah terpetakan dengan baik oleh penelitian sebelumnya, tetapi karakter dari zona hidrotermal belum terpetakan. Hal tersebut dapat diselesaikan dengan pengukuran metode Self Potential dan Electrical Resistivity Tomography yang dapat mengetahui distribusi anomali potensial dan resistivitasnya. Penelitian ini bertujuan untuk memetakan anomali potensial, mengetahui distribusi resistivitas di bawah permukaan, serta memodelkan bentuk geometri dari sumber anomali potensial dari zona hidrotermal Gunung Bromo dengan menggunakan Ensemble Kalman Inversion (EKI). Lintasan ERT yang digunakan sebanyak 4 lintasan di wilayah utara-timur laut Kawah Bromo dengan panjang lintasan mencakup 800 meter, 440 meter, 600 meter, dan 1000 meter dengan 6 Loop lintasan SP yang saling bersinggungan dengan lintasan ERT. Hasil penelitian ERT lintasan 1, lintasan 2, lintasan 3, dan lintasan 4 menunjukkan adanya zona konduktif yang diindikasi sebagai zona hidrotermal dengan nilai resistivitas berturut-turut sebesar < 203 Ωm di kedalaman > 69.1 meter, < 211 Ωm di kedalaman > 80 meter, < 134 Ωm di kedalaman < 69.1 meter, dan < 157 Ωm di kedalaman > 69.1 meter. Anomali SP menunjukkan nilai positif > 10 mV pada area barat (dekat kaldera Gunung Bromo) dan memanjang ke arah timur laut. Berdasarkan analisis ERT dan SP dengan menggunakan Inversi EKI, area aliran zona hidrotermal positif berada pada lintasan 3 ERT dengan nilai anomali SP 98.4 mV pada kedalaman 60.1 meter dengan bentuk geometri vertikal silinder. Terdapat kemungkinan zona patahan atau perbedaan litologi ditemukan pada lintasan yang sama pada kedalaman 51.3 meter dengan bentuk geometri vertikal silinder. Selain itu pada lintasan ERT 1, area zona hidrotermal didapatkan pada kedalaman 76.03 meter dengan anomali SP positif 64 mV.
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Mount Bromo is an active volcano with an active hydrothermal system that plays a role in the eruption process. The shallow hydrogeological zone has been well mapped by previous research, but the characteristics of the hydrothermal zone have not yet been mapped. This can be addressed through measurements using the Self-Potential and Electrical Resistivity Tomography methods, which can determine the distribution of potential and resistivity anomalies. This study aims to map potential anomalies, determine the distribution of subsurface resistivity, and model the geometric shape of the source of potential anomalies from the hydrothermal zone of Mount Bromo using Ensemble Kalman Inversion (EKI). Four ERT lines were used in the north-northeast region of the Bromo Crater, with line lengths of 800 metres, 440 metres, 600 metres, and 1000 metres, along with 6 SP line loops intersecting the ERT lines. The ERT survey results for lines 1, 2, 3, and 4 indicate the presence of conductive zones, interpreted as hydrothermal zones, with resistivity values of < 203 Ωm at depths > 69.1 metres, < 211 Ωm at a depth of > 80 metres, < 134 Ωm at a depth of < 69.1 metres, and < 157 Ωm at a depth of > 69.1 metres. The SP anomaly shows a positive value of > 10 mV in the western area (near the Mount Bromo caldera) and extends towards the north-east. Based on ERT and SP analysis using EKI inversion, the positive hydrothermal zone flow area is located on ERT line 3 with an SP anomaly value of 98.4 mV at a depth of 60.1 metres, exhibiting a vertical cylindrical geometry. Possibility of fault or lithological differences zone was found on the same profile at a depth of 51.3 metres, with a vertical cylindrical geometry. Furthermore, on ERT Profile 1, a hydrothermal zone was identified at a depth of 76.03 metres with a positive SP anomaly of 64 mV.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Anomali SP, Resistivitas ERT, Zona Hidrotermal, Ensemble Kalman Inversion, Model Geometri, Self-Potential Anomaly, ERT Resistivity, Hydrothermal Zone, Ensemble Kalman Inversion, Geometric Model
Subjects:	G Geography. Anthropology. Recreation > GB Physical geography > GB1199.5 Geothermal resources H Social Sciences > HV Social pathology. Social and public welfare > HV551.5.I4 Hazard mitigation Q Science > QE Geology > QE601 Geology, Structural
Divisions:	Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Geophysics Engineering > 33201-(S1) Undergraduate Thesis
Depositing User:	Diman Iakunu Suhada
Date Deposited:	20 Jul 2026 02:56
Last Modified:	20 Jul 2026 02:56
URI:	http://repository.its.ac.id/id/eprint/135508

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