Joint Inversion Data Gayaberat Dan Magnetik Untuk Pemodelan Struktur Bawah Permukaan Sistem Panas Bumi Di Dieng, Jawa Tengah

Muhammad, Raffa Rasqy (2026) Joint Inversion Data Gayaberat Dan Magnetik Untuk Pemodelan Struktur Bawah Permukaan Sistem Panas Bumi Di Dieng, Jawa Tengah. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Lapangan Panas Bumi Dieng merupakan sistem panas bumi vulkanik yang berkembang pada lingkungan geologi kompleks akibat aktivitas vulkanisme dan struktur geologi. Penelitian ini bertujuan untuk menganalisis karakteristik struktur bawah permukaan berdasarkan hasil joint inversion data gayaberat dan magnetik, serta membandingkan hasil inversi tunggal dengan joint inversion berbasis cross-gradient constraint untuk menunjukkan konsistensi struktur geometri dan penurunan ambiguitas interpretasi (non-uniqueness). Data gayaberat diperoleh dari model gravitasi global GGMPlus, sedangkan data magnetik berupa data lapangan. Proses inversi dilakukan menggunakan perangkat lunak SimPEG dengan pendekatan cross-gradient constraint. Hasil joint inversion menunjukkan adanya zona kontras suseptibilitas magnetik rendah hingga negatif yang dominan di bagian timur–tenggara daerah penelitian di sekitar Kawah Sikidang, diinterpretasikan sebagai zona alterasi hidrotermal intensif dan jalur migrasi fluida panas bumi. Zona kontras suseptibilitas tinggi teridentifikasi di bagian barat–utara di sekitar Kawah Sileri dan Kawah Siglagah, diinterpretasikan sebagai batuan vulkanik kompak yang belum mengalami alterasi signifikan. Variasi kontras densitas yang signifikan hanya terjadi pada kedalaman dangkal hingga sekitar 1.000 m. Pola distribusi anomali menunjukkan keterkaitan dengan struktur dominan berarah baratlaut–tenggara (NW–SE). Secara kuantitatif, inversi tunggal menghasilkan rata-rata RMS error sebesar 6,54% dibandingkan 8,05% pada joint inversion, namun secara kualitatif joint inversion menghasilkan model yang lebih stabil, bebas artefak inversi, dan memiliki batas struktur yang lebih jelas sehingga lebih mampu mengurangi ambiguitas interpretasi dibandingkan inversi tunggal.
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The Dieng Geothermal Field is a volcanic geothermal system developed within a complex geological setting influenced by volcanic activity and geological structures. This study aims to analyze the subsurface structural characteristics based on the joint inversion of gravity and magnetic data, and to compare the results of single inversion with cross-gradient constrained joint inversion in order to demonstrate structural geometry consistency and reduced interpretation ambiguity (non-uniqueness). Gravity data were obtained from the GGMPlus global gravity model, while magnetic data were acquired from field measurements. The inversion process was conducted using the SimPEG framework with a cross-gradient constraint approach. The joint inversion results indicate the presence of low to negative magnetic susceptibility contrast zones dominant in the eastern–southeastern part of the study area around Kawah Sikidang, interpreted as intensive hydrothermal alteration zones and geothermal fluid migration pathways. High susceptibility contrast zones are identified in the western–northern part around Kawah Sileri and Kawah Siglagah, interpreted as compact volcanic rocks that have not undergone significant alteration. Significant density contrast variations only occur at shallow depths of up to approximately 1,000 m. The anomaly distribution pattern is associated with the dominant northwest–southeast (NW–SE) structural trend. Quantitatively, single inversion produces a lower average RMS error of 6.54% compared to 8.05% for joint inversion; however, qualitatively, joint inversion produces a more stable model, free from inversion artifacts, with clearer structural boundaries, thus better reducing interpretation ambiguity compared to single inversion.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	joint inversion, gayaberat, magnetik, cross-gradient, panas bumi Dieng, SimPEG,joint inversion, gravity, magnetic, Dieng geothermal field, cross-gradient, SimPEG
Subjects:	T Technology > TN Mining engineering. Metallurgy > TN269 Prospecting--Geophysical methods
Divisions:	Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Geophysics Engineering > 33201-(S1) Undergraduate Thesis
Depositing User:	Raffa Rasqy Muhammad
Date Deposited:	22 Jul 2026 04:15
Last Modified:	22 Jul 2026 04:15
URI:	http://repository.its.ac.id/id/eprint/136194

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