Pemodelan Inversi 3D Data GGMPlus Untuk Identifikasi Area Rawan Likuefaksi di Indonesia

Rodhiyah, Umu Dwi (2025) Pemodelan Inversi 3D Data GGMPlus Untuk Identifikasi Area Rawan Likuefaksi di Indonesia. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Likuefaksi merupakan fenomena hilangnya kekuatan geser tanah akibat peningkatan tekanan pori saat terjadi guncangan gempa, sehingga tanah berperilaku seperti cairan. Penelitian ini bertujuan mengidentifikasi zona densitas rendah sebagai indikator awal potensi likuefaksi menggunakan pemodelan inversi 3D berdasarkan data gayaberat GGMPlus di wilayah Indonesia. Proses inversi dilakukan dengan perangkat lunak Grablox yang mengimplementasikan metode Singular Value Decomposition (SVD) dan Occam inversion. Hasil pemodelan menunjukkan nilai rata-rata densitas keseluruhan di masing-masing lokasi adalah sekitar 2,518 g/cm³ di Yogyakarta, 2,348 g/cm³ di Lombok, 2,584 g/cm³ di Kalimantan, 2,472 g/cm³ di Sulawesi, 2,515 g/cm³ di Pulau Obi, 2,509 g/cm³ di Pulau Yapen, dan 2,457 g/cm³ di Sumatera. Area berdensitas rendah yang berwarna biru di wilayah Sumatera, Yogyakarta, Lombok, Sulawesi, dan Pulau Yapen, umumnya berada pada kedalaman 0,2–1 km dan dikelilingi oleh material berdensitas tinggi. Zona tersebut diinterpretasikan sebagai lapisan jenuh air atau batuan lepas yang berpotensi menjadi titik lemah saat terjadi guncangan seismik. Sementara itu, wilayah Pulau Tarakan dan Pulau Obi menunjukkan distribusi densitas yang lebih homogen dan stabil, dengan potensi likuefaksi yang rendah.
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Liquefaction is a phenomenon where the shear strength of soil is lost due to increased
pore pressure during seismic shaking, causing the soil to behave like a liquid. This study aims
to identify low-density zones as preliminary indicators of liquefaction potential using 3D
inversion modeling based on GGMPlus gravity data across various regions in Indonesia. The
inversion process was carried out using the Grablox software, which implements the Singular
Value Decomposition (SVD) and Occam inversion methods. The modeling results show that
the average bulk density values for each study area are approximately 2.518 g/cm³ in
Yogyakarta, 2.348 g/cm³ in Lombok, 2.584 g/cm³ in Kalimantan, 2.472 g/cm³ in Sulawesi,
2.515 g/cm³ in Obi Island, 2.509 g/cm³ in Yapen Island, and 2.457 g/cm³ in Sumatra. Low�density zones indicated in blue appear in Sumatra, Yogyakarta, Lombok, Sulawesi, and Yapen
Island, typically occurring at depths of 0.2–1 km and are surrounded by high-density material.
These zones are interpreted as water-saturated layers or unconsolidated sediments that could
act as weak points during seismic events. In contrast, the Kalimantan and Obi Island region
shows a more homogeneous and stable density distribution, indicating a lower potential for
liquefaction.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Densitas, Gayaberat, GGMPlus, Likuefaksi.
Subjects:	G Geography. Anthropology. Recreation > GB Physical geography
Divisions:	Faculty of Civil Engineering and Planning > Geomatics Engineering > 29202-(S1) Undergraduate Thesis
Depositing User:	Umu Dwi Rodhiyah
Date Deposited:	24 Jul 2025 08:51
Last Modified:	24 Jul 2025 08:51
URI:	http://repository.its.ac.id/id/eprint/121521

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