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Identifikasi Batuan Penudung dan Reservoar Panas Bumi Berdasarkan Pemodelan Inversi 2D Magnetotellurik Studi Kasus: Guci, Jawa Tengah

ZUKHRUF DELVA JANNET, Dr. Eddy Hartantyo, M.Si.

2019 | Skripsi | S1 GEOFISIKA

Guci merupakan daerah prospek panas bumi yang terletak di sisi barat laut Gunung Slamet. Secara geologi, Guci terletak di daerah depresi (graben) yang terbentuk akibat deformasi dan alterasi hidrotermal. Adanya manifestasi panas bumi di permukaan mengindikasi keterdapatan sistem panas bumi di bawah permukaan Guci. Penelitian dengan metode magnetotellurik (MT) dilakukan untuk mengidentifikasi sistem panas bumi (batuan penudung dan reservoar) daerah penelitian berdasarkan sebaran nilai resistivitas. Survei geofisika menggunakan metode MT yang terdiri dari dua lintasan berorientasi barat laut-tenggara dan timur laut-barat daya dilakukan untuk dapat memodelkan sistem panas bumi di bawah permukaan Guci berdasarkan nilai resistivitas batuan. Pemodelan bawah permukaan Guci dilakukan dengan menggunakan metode inversi 2D. Selain itu, analisis dengan metode tensor fase, swift strike, dan komponen riil induction vector juga dilakukan untuk menentukan arah geoelectrical strike dominan daerah penelitian. Berdasarkan hasil analisis metode tensor fase, swift strike dan komponen riil induction vector, diketahui bahwa arah geoelectrical strike dominan daerah penelitian adalah N97,5E. Sedangkan berdasarkan model hasil inversi 2D magnetotellurik diinterpretasikan bahwa zona konduktif dengan nilai resistivitas di bawah 12 Ohm.m berasosiasi dengan lempung konduktif (smectite) yang bertindak sebagai batuan penudung pada sistem panas bumi daerah penelitian, dan zona dengan nilai resistivitas 12-120 Ohm.m diinterpretasikan sebagai reservoar panas bumi daerah penelitian.

Guci is one of geothermal prospect area that is located on the northwest side of Mount Slamet. Geologically, Guci is a graben area due to deformation and hydrothermal alteration. The indication of the geothermal system below Guci area is proved by geothermal manifestation on the surface, that is hot springs. The research using magnetotelluric method was conducted to determine the direction of dominant geoelectrical strike and identify geothermal system (clay cap and reservoir) in the research area based on the distribution of resistivity values. The geophysical survey using the magnetotelluric (MT) method which consists of two line in the direction of northwest-southeast and northeast-southwest is done to map the geothermal system in the subsurface of Guci based on rock resistivity values. Guci subsurface modelling is done by using 2D inversion method. In addition, the analysis of phase tensor, swift strike and real induction vector component method was also performed to determine the direction of dominant geoelectrical strike in the research area. According to the result of the phase tensor, swift strike and real component of induction vector analysis, the direction of dominant geoelectrical strike in the research area is N97,5E. While based on 2D inversion of magnetotelluric method, it can be interpreted that the conductive zone with a resistivity value of less than 12 Ohm.m is related to a conductive clay (smectite) which acts as clay cap in the research area, whereas zone which has resistivity value of 12-120 Ohm.m is interpreted as a geothermal reservoir of research area.

Kata Kunci : guci, magnetotellurik, geoelctrical strike, inversi 2D

  1. S1-2019-366023-abstract.pdf  
  2. S1-2019-366023-bibliography.pdf  
  3. S1-2019-366023-tableofcontent.pdf  
  4. S1-2019-366023-title.pdf