Analisis Dimensionalitas dan Geoelectrical Strike menggunakan Data Phase tensor Magnetotelurik

Pinandita, Aussie Anindya Nari (2023) Analisis Dimensionalitas dan Geoelectrical Strike menggunakan Data Phase tensor Magnetotelurik. Other thesis, Institut Teknologi Sepuluh Nopember.

Text 03411940000018-Undergraduate_Thesis.pdf - Accepted Version Restricted to Repository staff only until 1 September 2025. Download (12MB) | Request a copy

Abstract

Distorsi akibat heterogenitas di dekat permukaan, kontak batas, dan efek topografi pada data Magnetotelurik (MT) ditandai dengan pergeseran statis pada kurva resistivitas. Adanya efek distorsi juga menyebabkan dimensionalitas bawah permukaan bukanlah dimensionalitas sebenarnya. Selain itu, arah struktur utama yang tidak diketahui saat pengukuran menyebabkan sumbu pengukuran yang tidak tegak lurus dan memotong arah struktur utama. Permasalahan tersebut dapat menyebabkan kesalahan interpretasi. Oleh karena itu, diperlukan suatu properti yang tidak terpengaruh oleh distorsi untuk menentukan dimensionalitas dan geoelectrical strike, yakni phase tensor. Hasil penelitian menunjukkan bahwa data MT didominasi oleh struktur dimensi 1D dan 2D pada periode rendah yang diestimasi sebagai keberadaan lapisan zona konduktif yang memanjang dalam satu arah dan didapatkan perselingan dimensionalitas 3D di periode rendah yang diestimasi sebagai adanya struktur geologi kompleks seperti patahan sebagai jalur manifestasi. Pada periode tinggi didominasi oleh struktur 3D yang diestimasi sebagai zona transisi menuju variasi konduktivitas yang lebih komprehensif dari berbagai arah seperti keberadaan heat source. Selain itu, didapatkan informasi geoelectrical strike berdasarkan phase tensor dan tipper strike sebesar 10o dan 55o yang terkonfirmasi oleh adanya struktur geologi di lokasi penelitian dengan orientasi arah yang sama. Nilai RMS error menggunakan rotasi tipper strike menunjukkan hasil yang lebih kecil dan representatif. Hasil pemodelan 2D menunjukkan distribusi nilai resistivitas rendah (1-10 ohmm) diduga batuan alterasi argilik sebagai lapisan clay cap, distribusi nilai resistivitas sedang (11 – 200 ohmm) diduga batugamping (Tmtl) sebagai zona reservoir di bawah Cisolok dan batu andesit di bawah Cisukarame, dan distribusi nilai resistivitas tinggi (201 – 1024 ohmm) diduga intrusi andesit (Qvl) dan dasit (Tmda) sebagai sumber panas.
===========================================================================================================================
Distortion due to near-surface heterogeneity in Magnetotelluric (MT) data is characterized by static shifts in the resistivity curve. Also, the direction of the main structure that is not known during survey causes the measurement axis to be not perpendicular and intersects the direction of the main structure. These problems can lead to misinterpretation. Therefore, this study uses property that iss not affected by distortion to determine dimensionality and geoelectrical strike, namely the phase tensor. The results show that the MT data in geothermal area is dominated by 1D and 2D dimensional structures at low periods which are estimated as the presence of conductive layer that extends in one direction. 3D dimensionality that occurs at low periods is estimated as the presence of complex geological structures. The high period is dominated by the 3D dimensionality which is estimated as the presence of heat source. In addition, geoelectrical strike information was also obtained based on the phase tensor and tipper strike that are 10o and 55o which are confirmed by the presence of geological structures with the same orientation in North East – South West. The RMS error value using tipper strike rotation is smaller and give more representative results. The results of 2D modeling show the distribution of low resistivity values (1-10 ohmm) is estimated to be argillic alteration rocks as clay cap layers, medium resistivity values (11–200 ohmm) is estimated to be limestone (Tmtl) as the reservoir zone below Cisolok and andesite rock below Cisukarame, and the high resistivity zone (201–1024 ohmm) is estimated to be andesite (Qvl) and dacite (Tmda) intrusions as the heat sources.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Dimensionalitas, Geoelectrical Strike, Magnetotelurik, Panas bumi, Phase tensor Static shift; Dimensionality, Geoelectrical Strike, Magnetotelluric, Geothermal, Phase Tensor Static shift.
Subjects:	Q Science Q Science > QC Physics > QC610.3 Electric conductivity Q Science > QE Geology
Divisions:	Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Geophysics Engineering > 33201-(S1) Undergraduate Thesis
Depositing User:	Aussie Anindya Nari Pinandita
Date Deposited:	04 Oct 2023 10:11
Last Modified:	04 Oct 2023 10:11
URI:	http://repository.its.ac.id/id/eprint/103569

Actions (login required)

View Item