Identifikasi Struktur Geologi dan Kontras Densitas Lereng Timur Gunung Api Lamongan, Probolinggo, Jawa Timur Menggunakan Metode Gayaberat

Sijabat, Jhon Christ Rivand (2025) Identifikasi Struktur Geologi dan Kontras Densitas Lereng Timur Gunung Api Lamongan, Probolinggo, Jawa Timur Menggunakan Metode Gayaberat. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Lereng timur Gunung Lamongan adalah salah satu area yang memiliki potensi panas bumi, dimana dijumpai adanya manifestasi fumarole dan mata air panas dengan suhu antara 35°C hingga 45°C .Sistem panas bumi umumnya memiliki hubungan erat dengan pengaturan tektonik dan aktivitas vulkanik. Struktur geologi di sekitar sistem mata air panas dapat berfungsi sebagai jalur aliran fluida panas dari bawah permukaan. Namun, penelitian terkait identifikasi struktur pada di area ini masih sedikit. Penelitian menggunakan metode gayaberat satelit di area ini dilakukan dengan tujuan mengetahui struktur geologi serta kontras densitas bawah permukaan melalui pemodelan 3 dimensi. Data yang dipakai dalam hal ini meliputi data satelit (data GGMPlus). Pengambilan data difokuskan pada area timur lereng Gunung Lamongan, menggunakan gayaberat satelit GGMPlus dengan spasi grid 200 meter. Dari hasil pengukuran satelit, kemudian dikoreksi meliputi koreksi lintang, koreksi udara bebas, koreksi bouguer, dan koreksi medan untuk mendapatkan nilai anomali bouguer lengkap. Penggunaan filter kontinuasi dilakukan untuk mendapatkan anomali residual area penelitian. Anomali residual kemudian digunakan untuk analisa secara kualitatif menggunakan filter deteksi turunan horizontal
(Horizontal Derivative) dan turunan vertikal kedua (Second Vertical Derivative). Proses inversi data gayaberat diperlukan untuk mendapatkan nilai sebaran densitas bawah permukaan serta untuk memvalidasi keberadaan struktur area timur lereng Gunung Lamongan. Analisis gayaberat satelit di timur Gunung Lamongan mengungkap dua struktur sesar bawah permukaan berupa sesar normal di barat laut dan sesar naik di timur area studi, dengan orientasi dominan barat laut–tenggara. Konfirmasi diperoleh dari peta residual, analisis turunan, dan kelurusan. Pemodelan 3D menunjukkan pola anomali konsisten yang mengindikasikan keberadaan tiga jenis batuan bawah permukaan: tuff lapilli, tuffaceous breccia, dan intrusi basalt.
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The eastern slope of Mount Lamongan is one of the areas with geothermal potential, where fumarole manifestations and hot springs with temperatures ranging from 35°C to 45°C are found. Geothermal systems are generally closely related to tectonic settings and volcanic activity. Geological structures around hot spring systems can act as pathways for the flow of hot fluids from below the surface. However, studies related to the identification of structures in this area are still limited.This research utilizes satellite gravity methods in this area to identify geological structures and subsurface density contrasts through three-dimensional modeling. The data used includes satellite data (GGMPlus data). Data acquisition was focused on the eastern slope of Mount Lamongan, using GGMPlus satellite gravity data with a 200-meter grid spacing.The satellite measurements were corrected by applying latitude correction, free-air correction, Bouguer correction, and terrain correction to obtain complete Bouguer anomaly values. Continuation filtering was applied to extract the residual anomaly in the study area. The
residual anomalies were then analyzed qualitatively using horizontal derivative and second vertical derivative filters.Gravity data inversion was conducted to obtain the subsurface density distribution and to validate the existence of geological structures in the eastern slope area of Mount Lamongan. The satellite gravity analysis in the eastern part of Mount Lamongan revealed two subsurface fault structures, including a normal fault in the northwest and a thrust fault in the eastern part of the study area, with a dominant northwest–southeast orientation. These findings were confirmed through residual maps, derivative analyses, and lineament analysis.The 3D modeling shows consistent anomaly patterns that indicate the presence of three types of subsurface rocks: lapilli tuff, tuffaceous breccia, and basaltic intrusion.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Density, Gravity method, Geological structure, Densitas, Metode gayaberat, Struktur geologi
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) > TA169.6 Fault location (Engineering)
Divisions:	Faculty of Civil Engineering and Planning > Geophysics Engineering > 33201-(S1) Undergraduate Thesis
Depositing User:	Jhon Christ Rivand Sijabat
Date Deposited:	28 Jul 2025 10:00
Last Modified:	28 Jul 2025 10:00
URI:	http://repository.its.ac.id/id/eprint/122336

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