Analisis Metode Smoothing Dan Mode Polarisasi Dalam Pemodelan Inversi 2D Data Magnetotelurik Untuk Identifikasi Struktur Geologi Zona Rembang

Ilmawan, Roby Zidni (2021) Analisis Metode Smoothing Dan Mode Polarisasi Dalam Pemodelan Inversi 2D Data Magnetotelurik Untuk Identifikasi Struktur Geologi Zona Rembang. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Berdasarkan fisiografi lokasi penelitian terletak pada Zona Rembang, di daerah tersebut terdapat beberapa struktur geologi seperti sesar dan lipatan. Pusat Studi Gempa Bumi Nasional (PuSGeN) (2017) menyatakan bahwa di daerah Jawa Timur dilalui oleh sesar-sesar aktif yang salah satunya adalah Sesar Kendeng. Penelitian ini menggunakan metode magnetotelurik (MT) karena memiliki penetrasi yang cukup dalam untuk mengidentifikasi struktur-struktur geologi tersebut. Pada penelitian ini digunakan tiga metode smoothing kurva yaitu metode numeric, metode D+, dan metode sutarno. Pada hasil analisis smoothing didapatkan bahwa metode numeric baik digunakan pada data yang fluktuatif. Metode D+ baik digunakan pada data observasi yang memiliki trend halus, dan metode sutarno dapat digunakan untuk menguji keselarasan pola antara kurva resistivitas semu dan kurva fase. Selain itu pada pengolahan metode MT terdapat tiga mode polarisasi yaitu mode TE (Tranverse Electric), mode TM (Transverse Magnetic), dan mode TE-TM. Tiap mode tersebut menghasilkan kualitas model yang berbeda dalam menggambarkan struktur geologi. Hasil interpretasi pada penelitian ini menunjukan bahwa ketiga mode tersebut dapat mengidentifikasi struktur geologi dengan cukup baik. Pada hasil tersebut didapatkan kedalaman sesar segmen Kendeng diperkirakan <7000 m dengan range resistivitas 4-100 ohm.m. Terdapat juga struktur lipatan di kedalaman dangkal (<3000 m) dan dugaan lipatan yang lebih dalam pada kedalaman >8000 m. Hasil pengolahan data menggunakan mode TE memiliki sensitivitas yang baik dalam memetakan resisitivitas secara lateral, mode TM baik dalam memetakan resistivitas secara vertikal, adapun mode TE-TM mampu memetakan kontras nilai resistivitas baik secara lateral maupun vertikal.
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Based on the physiography, the research location is located in the Rembang Zone, in that area there are several geological structures such as faults and folds. The National Earthquake Study Center (PuSGeN) (2017) states that the East Java area is traversed by active faults, one of which is the Kendeng Fault. This study uses the magnetotelluric (MT) method because it has a deep enough penetration to identify these geological structures. In this study, three methods of smoothing curves were used, namely the numerical method, the D+ method, and the Sutarno method. The results of the smoothing analysis show that the numerical method is good for use on fluctuating data. The D+ method is good for observation data that has a smooth trend, and the Sutarno method can be used to test the alignment of the pattern between the apparent resistivity curve and the phase curve. In addition to the processing of the MT method, there are three polarization modes, namely TE (Tranverse Electric) mode, TM (Transverse Magnetic) mode, and TE-TM mode. Each of these modes produces a different quality model in describing the geological structure. The interpretation results in this study indicate that the three modes can identify geological structures quite well. In these results, the fault depth of the Kendeng segment is estimated to be <7000 m with a resistivity range of 4-100 ohm.m. There are also fold structures at shallow depths (<3000 m) and presumed deeper folds at depths >8000 m. The results of data processing using TE mode have good sensitivity in mapping resistivity laterally, TM mode is good in mapping resistivity vertically, while TE-TM mode is able to map contrast resistivity values both laterally and vertically.

Item Type:	Thesis (Undergraduate)
Uncontrolled Keywords:	Magnetotelurik, Mode Polarisasi, Resistivitas, Smoothing, Magnetotelluric, polarization Mode, Resistivity, Smoothing
Subjects:	G Geography. Anthropology. Recreation > G Geography (General) > G70.217 Geospatial data
Divisions:	Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Geophysics Engineering > 33201-(S1) Undergraduate Thesis
Depositing User:	Roby zidni ilmawan
Date Deposited:	27 Aug 2021 03:57
Last Modified:	27 Aug 2021 03:57
URI:	http://repository.its.ac.id/id/eprint/89913

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