Aplikasi Metode Spectral Decomposition pada Data Gaya Berat: Studi Kasus Pemodelan Zona Subduksi Bagian Timur Pulau Jawa

Pradana, Farid Hendra (2017) Aplikasi Metode Spectral Decomposition pada Data Gaya Berat: Studi Kasus Pemodelan Zona Subduksi Bagian Timur Pulau Jawa. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Pemodelan data gaya berat adalah proses pembuatan model geometri dan perhitungan persebaran nilai masa jenis bawah permukaan. Pemodelan data gaya berat biasanya menggunakan metode inversi dimana subjektivitas interpreter sangat memengaruhi model yang dihasilkan meskipun telah dikontrol oleh data sekunder lainnya, misalnya data geologi. Spectral decomposition merupakan salah satu metode yang diharapkan dapat menjadi alternatif dalam melakukan pemodelan geometri data gaya berat dimana model geometri didekati langsung dari bentukan gelombang hasil filter tiap kandungan frekuensi yang diposisikan pada suatu kedalaman dengan parameter tertentu sehingga didapatkan model yang lebih objektif. Penelitian ini bertujuan mencari nilai parameter dan jenis filter yang sesuai untuk digunakan dalam penggunaan metode spectral decomposition data gaya berat dengan studi kasus pemodelan zona subduksi bagian Timur Pulau Jawa. Parameter-parameter tersebut antara lain adalah, hubungan antara nilai cut off frekuensi spasial dan kedalaman, nilai skala model, dan jenis filter. Hasil penelitian menunjukkan bahwa hubungan cut off panjang gelombang (λ) dan kedalaman (d) yang sesuai adalah d=1/10 λ, skala model yang sesuai adalah normalisasi sebesar d, dan jenis filter yang sesuai adalah kombinasi antara Band-Pass dan Low-Pass Filter. Model hasil metode spectral decomposition terbukti cukup baik digunakan sebagai model awal proses inversi gaya berat. ========================================================================== Gravity modelling is a procces that is conducted to know about the geometry and distribution of density value in subsurface. Gravity modelling usually done by doing inversion process where the subjectivity of intrepreter greatly affect the result model eventhogh it could be controlled by secondary data, such as, geological data. In this research, it had been conducted a validation and application process of using spectral decomposition method as an alternative method to model the gravity data with the study case of eastern java subduction zone modelling which the geometry model was directly approached by waveform of the filter and resulted in each frequency content positioned at a depth of a certain parameter. These parameters were the correlation between the cutoff value of the spatial frequency and depth, the model scale value, and the type of filter used. From the research results, it was known that the best correlation between wavelength (λ) and depth (d) to create a model is d = 1/10 λ, the model scale of each corresponding depth was normalized with interval of d, and the corresponding filter type that fit the model well was the combination between Band-Pass and Low-Pass Filter. The resulting model of the spectral decomposition method was very well used as the initial model of gravity inversion process.

Item Type: Thesis (Undergraduate)
Uncontrolled Keywords: Gaya Berat, Filter Frekuensi, Parameter Spectral Decomposition, Pemodelan Geometri, Zona Subduksi Jawa, Gravity method, Frequency Filter, Spectral Decomposition Parameter, Geometry Modeling, Java Subduction Zone
Subjects: Q Science > QA Mathematics > QA404 Fourier series
Q Science > QC Physics
Divisions: Faculty of Civil Engineering and Planning > Geophysics Engineering > 33201-(S1) Undergraduate Thesis
Depositing User: Farid Hendra Pradana
Date Deposited: 16 Aug 2017 01:14
Last Modified: 16 Aug 2017 01:14
URI: http://repository.its.ac.id/id/eprint/42224

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