Luckytasari, Nadia Putri (2019) Perbandingan Mode TE, TM dan TE-TM Terhadap Pemodelan Inversi 2-D Data Magnetotelurik Pada Lapangan Panas Bumi Arjuno Welirang. Other thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Metode Magnetotelurik adalah metode geofisika yang dapat digunakan untuk mengetahui distribusi nilai resistivitas batuan di bawah permukaan bumi. Data tersebut kemudian diolah menggunakan prinsip fourier transform, robust processing dan seleksi crosspower hingga diperoleh vaiasi impedansi. Penelitian ini menggunakan data sekunder metode magnetotelurik sebanyak 30 titik pengukuran di daerah manifestasi panas bumi Arjuno Welirang dengan tipe sistem panas bumi vulkanik. Hasil pengolahan dan analisis data magnetotelurik kemudian diinversi untuk mengetahui pemodelan distribusi resistivitas bawah permukaan. Pada penelitian ini membahas sensitivitas dari mode TE (transverse electric), mode TM (transverse magnetic) dan mode TE-TM serta identifikasi sistem panas bumi daerah penelitian. Hasil pengolahan data dengan menggunakan mode TE memiliki sensitivitas yang baik dalam memetakan resistivitas rendah (konduktif) secara lateral, mode TM memiliki sensitivitas yang baik dalam memetakan resistivitas tinggi secara vertikal dan mode TE-TM memiliki sensitivitas yang baik dalam memetakan kontras nilai resistivitas secara lateral mapupun secara vertikal. Hasil inversi dengan mode TE tidak menunjukkan adanya struktur pada daerah penelitian, sedangkan hasil inversi dengan mode TM dan dengan mode TE-TM menunjukkan adanya struktur yang diperkirakan berupa sesar. Sistem panas bumi yang teridentifikasi berada pada Formasi Gunung Api Arjuno – Welirang (Qvaw). Lapisan batuan penudung (cap rock) dengan nilai resistivitas 7 – 12 Ωm setebal 2000 m yang diperkirakan berasal dari Lava Muda Produk Welirang (Qlw) dan Lava Arjuno (Qlar). Lapisan reservoir dengan nilai resistivitas 13 – 65 Ωm setebal 500 m yang diperkirakan sebagai Aliran Piroklastik Arjuno Welirang (Qapaw). Lapisan heat source dengan nilai resistivitas 70 – 300 Ωm setebal 3000 m yang diperkirakan berasal dari Lava Pra Arjuno Welirang (Qlaw). Kontras resistivitas pada resistivitas rendah yang diduga sebagai Sesar Welirang dan Sesar Padusan.
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Magnetotelluric method is a geophysical method that can be used to determine the distribution of resistivity values of rocks beneath the earth's surface. The data is then processed using the fourier transform, robust processing and crosspower selection principles to obtain impedance measurements. This study uses secondary data on magnetotelluric method as many as 30 measurement points in the Arjuno Welirang geothermal manifestation area with a type of volcanic geothermal system. The results of processing and analysis of magnetotelluric data were then inversed to determine the modeling of subsurface resistivity distributions. This study discusses the sensitivity of TE (transverse electric), TM (transverse magnetic) and TE-TM modes as well as identification of geothermal systems in the study area. The results of data processing using TE mode have good sensitivity in mapping low resistivity (conductive) laterally, TM mode has good sensitivity in mapping vertically high resistivity and TE-TM mode has good sensitivity in mapping resistivity values laterally or even vertically. The inversion result with TE mode does not indicate the presence of structures in the study area, while the inversion results with TM mode and TE-TM mode indicate the presence of a structure that is estimated to be a fault. The identified geothermal system is in the Arjuno - Welirang Volcano Formation (Qvaw). Cap rock with a resistivity value of 7 - 12 Ωm and thick as 2000 m which is estimated to come from Young Lava Welirang Products (Qlw) and Lava Arjuno (Qlar). Reservoir with a resistivity value of 13 - 65 Ωm and thick as 500 m which is estimated as Arjuno Welirang Pyroclastic Flow (Qapaw). Heat source with resistivity values of 70 - 300 Ωm and thick as 3000 m which is estimated to come from Lava Pra Arjuno Welirang (Qlaw). Contrast resistivity at low resistivity is suspected as Welirang Fault and Padusan Fault.
| Item Type: | Thesis (Other) |
|---|---|
| Additional Information: | RSGf 538.3 Luc p-1 2019 |
| Uncontrolled Keywords: | inversi 1-D, inversi 2-D, mode TE, mode TE-TM, mode TM |
| Subjects: | Q Science > QC Physics > QC20.7.F67 Fourier transformations Q Science > QC Physics > QC271.8.C3 Calibration Q Science > QC Physics > QC610.3 Electric conductivity Q Science > QE Geology > QE601 Geology, Structural |
| Divisions: | Faculty of Civil, Environmental, and Geo Engineering > Geophysics Engineering > 33201-(S1) Undergraduate Theses |
| Depositing User: | Nadia Putri Luckytasari |
| Date Deposited: | 02 May 2024 03:23 |
| Last Modified: | 02 May 2024 03:23 |
| URI: | http://repository.its.ac.id/id/eprint/64433 |
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