PEMODELAN DATA MT 2-D DAN PERBANDINGAN MODUS TE & TM STUDI KASUS: LAPANGAN PANASBUMI MARANA, KABUPATEN DONGGALA, SULAWESI TENGAH; 2D MAGNETOTELURIC DATA PROCESSING AND COMPARISON BETWEEN TE & TM MODE CASE STUDY: MARANA GEOTHERMAL FIELD, DONGGALA REGENCY, CENTRAL SULAWESI

Kirana, Kadya, Eddy Hartantyo

2016 | Skripsi | FMIPA

Marana Geothermal Field is located in Donggala Regency, Central Sulawesi. The data was acquired in 2011. The total measured points are 37 and divided into 8 lines, with southwest – northeast trending and space between points about 1500 – 2000 meters. Geologically, this area is located around northwest – southeast Palu – Koro fault. Magnetotelluric data processing was done by using TE Mode (Transverse Electric), TM Mode (Transverse Magnetic), and TE-TM Mode. The results of all three modes show various responses. From the result of inversion with TE mode, response to the geological structure is absent, while the inversion with TM mode indicates a fault dividing the high resistivity distribution. Inversion with TE-TM mode shows better subsurface response. The result of combined TE-TM inversion shows the most comprehensive result. The result of magnetotelluric data processing indicates a low resistivity distribution from near the surface until the depth of 1000 meter, which is interpreted as the cap rock. Reservoir zone is indicated by the intermediate resistivity distribution beneath the cap rock (between the depth of 750 – 2000 meter), while the area with high resistivity distribution is divided into two parts; the southwest area and northeast area of the line. The southwest area and northeast area are separated by a lower resistivity, which is interpreted as a fault. The result of Magnetotelluric inversion shows the same response with the result of Geomagnet and Gravity interpretationdata processing, which shows linearity with northwest – southeast trending. This linearity indicates a fault that controlled geothermal system in the area.

Kata Kunci : Magnetotelluric; Geothermal; TE and TM mode; Marana; Donggala