Pemodelan 3-D Struktur Bawah Permukaan Pulau Flores Dan Zona Sesar Belakang Busur Berdasarkan Analisis Data Gravitasi

Titi, Yopiter Lukas Alexander (2016) Pemodelan 3-D Struktur Bawah Permukaan Pulau Flores Dan Zona Sesar Belakang Busur Berdasarkan Analisis Data Gravitasi. Masters thesis, Institut Teknologi Sepuluh Nopember Surabaya.

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Abstract

Telah dilakukan pemodelan tiga dimensi dan interpretasi struktur bawah permukaan pulau Flores dan zona sesar belakang busur berdasarkan analisis data gravitasi. Penelitian ini bertujuan untuk menganalisis secara kualitatif dan memodelkan struktur bawah permukaan dengan memanfaatkan data sekunder anomali gravitasi Bouguer lengkap. Data diperoleh dari Bureau Gravimetric international (BGI). Data anomali Bouguer lengkap diproyeksi ke bidang datar menggunakan metode Dampney pada ketinggian 26 km dan pemisahan anomali regional dan lokal dengan metode kontinuasi ke atas pada ketinggian 30 km. Interpretasi secara kualitatif menggunakan data anomali regional untuk menentukan gradien horisontal dan gradien tilt. Untuk pemodelan dilakukan terhadap data anomali gravitasi regional dan anomali lokal menggunakan Grablox dan Bloxer. Pembuatan model dilakukan dengan teknik inversi menggunakan metode dekomposisi nilai tunggal dan optimasi Occam. Hasil penelitian menunjukkan bahwa nilai gradien horisontal berkisar antara 0,00 hingga 0,9 mGal/km. Gradien horisontal dan gradien tilt dari anomali gravitasi regional berada di bagian Barat laut, Utara, dan Timur laut dari pulau Flores yang mana daerah tersebut merupakan kontak geologi. Berdasarkan model 3D dari anomali regional dan anomali residual, sesar belakang Flores diperkirakan berada mulai pada kedalaman 30 km, ketebalan kerak bumi di zona sesar belakang Flores diperkirakan hingga 30 km, sedangkan ketebalan kerak bumi dibagian busur pulau diperkirakan lebih dari 60 km. Keberadaan dapur magma di busur gunung api pulau Flores pada umumnya diperkirakan pada kedalaman 6 km
==========================================================================================The subsurface structure three dimensional modeling and interpretation of Flores island and back arc thrust zone has been done based on gravity data analysis. This research is aimed to analyze qualitatively and modeling subsurface structure was utilized a secondary data of complete Bouguer anomaly gravity. Data was obtained from Bureau Gravimetric International (BGI). Complete Bouguer anomaly data was projected to horizontal plane using Dampney method on 26 km heights and separation of the regional and local anomaly with upward continuation method on 30 km heights. Interpretation qualitatively using regional anomaly data to determine the horizontal gradient and tilt gradient. For modeling conducted on the regional gravity anomaly data and local anomaly using Grablox and Bloxer. The modelling construction was performed by inversion technique applying Singular Value Decomposition (SVD) method and Occam optimization. The result shows that horizontal gradient value ranging from 0,00 to 0,9 mGal/km. Horizontal gradient and tilt gradient of regional gravity anomaly located in the Northwest, North and Northeast of Flores island where the area is a geological contact. Based on the three dimensional model of regional and local anomalies, Flores back arc thrust was estimated to be started at depth of 30 km, the thickness of the crust in Flores back arc thust zone was estimated up to 30 km, while the thickness of the crust part of island arc was estimated at more than 60 km. The existence of magma chamber in the volcanic arc of Flores island generally was estimated at depth of 6 km

Item Type: Thesis (Masters)
Additional Information: RTFi 515.35 Tit p
Uncontrolled Keywords: Data gravitasi, Anomali Bouguer lengkap, Pemodelan tiga dimensi, Grablox, Bloxer
Subjects: Q Science > QC Physics > QC111 Density and specific gravity
Q Science > QE Geology > QE601 Geology, Structural
Divisions: Faculty of Mathematics and Science > Physics > 45201-(S1) Undergraduate Thesis
Depositing User: EKO BUDI RAHARJO
Date Deposited: 01 Apr 2020 02:31
Last Modified: 01 Apr 2020 02:31
URI: http://repository.its.ac.id/id/eprint/75629

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