PENDUGAAN KEBERADAAN ALIRAN SUNGAI BAWAH TANAH MENGGUNAKAN METODE GRADIO VERY LOW FREQUENCY (VLF) DI DAERAH GIRIJATI, PURWOSARI, GUNUNGKIDUL, YOGYAKARTA
DOI:
https://doi.org/10.12928/bfi-jifpa.v7i2.3441Abstract
Telah dilakukan penelitian pendugaan aliran sungai bawah tanah di daerah Girijati, Kecamatan Purwosari, Kabupaten Gunungkidul, Yogyakarta dengan menggunakan metode geofisika Gradio Very Low Frequency (VLF) Elektromagnetik (Gradient VLF-EM) untuk mengetahui respon VLF mode sudut tilt dan eliptisitas. Interpretasi dilakukan dari data VLF sudut tilt dan elliptisitas untuk mengestimasi aliran sungai bawah tanah yang diinterpretasi secara kualitatif dan kuantitatif. Akuisisi data dilakukan pada tanggal 9 – 15 Juli 2014. Pengolahan data menggunakan bahasa pemrograman Matlab. Interpretasi kualitatif dilakukan dengan pengolahan data yang difilter dengan moving average melalui filter Karous-Hajelt dan filter Fraser sehingga memperlihatkan anomali benda konduktif bawah tanah. Nilai kerapatan arus ekivalen dari lintasan 1 hingga lintasan 5 berkisar dari 0-1200%. Zona konduktif mempunyai kerapatan arus ekivalen ? 600%. Dari peta penampang rapat arus ekivalen lintasan 1 sampai dengan 5 diduga sungai bawah tanah di daerah Girijati, Kecamatan Purwosari Kabupaten Gunungkidul Yogyakarta mengalir dari Timur Laut ke Barat Daya, terdiri atas dua aliran sungai bawah tanah dan tidak saling berhubungan dengan kedalaman 10-70 meter.
Kata kunci: Gradient VLF-EM, respon VLF, zona konduktif.
References
Bosh, F.P., dan Müller, I., 2001,â€Continuous gradient VLF measurements: a new possibility for high resolution mapping of karst structuresâ€, Technical Articles, 19, 345–350.
Fraser, D.C., 1969, â€Contouring of VLF-EM dataâ€, Geophysics, 34, 958–967.
Grant, F. S dan West, G. F., 1965, “Interpretation theory in applied geophysicsâ€, New York: McGaw-Hill.
Hiskiawan, P., 2011, “Akuisisi data VLF-EM menggunakan teknik konvensional dan teknik gradio,“ Jurnal Fisika Himpunan Fisika Indonesia, 11 (1), 18-22.
Karous, M., dan Hjelt, S.E., 1983, â€Linear filtering of VLF dip-angle measurements,†Geophysical Prospecting, 31, 782–794.
Kusumayudha S.B. 2005, “Hidrogeologi karst dan geometri fraktal di daerah Gunungsewu,†Yogyakarta: Adicita.
Oskooi, B., dan Pedersen, L.B., 2005, â€Comparison between VLF and RMT methods. A combined tool for mapping conductivity changes in the sedimentary cover“, Journal of Applied Geophysics, 57, 227–241.
Pedersen, L.B., Bastani, M., dan Dynesius, L., 2005, “Ground water exploration using combined controlled source and RadioMagnetoTelluric techniquesâ€, Geophysics, 70, G8–G15.
Sasaki, Y., 2001, â€Full 3-D inversion of electromagnetic data on PCâ€, Journal of Applied Geophysics, 46, 45–54.
Santos, F.A.M., Mateus, A., Figueiras, J., dan Goncalves, M.A, 2006, “Mapping groundwater contamination around a landfill facility using the VLF-EM method — a case study,†Journal of Applied Geophysics, 60, 115–125.
Sismanto, Eddy, H., Sudarmadji, M., Nukman, dan Suryanto, W., 2003, “Tanggapan gelombang elektromagnetik frekuensi rendah (vlf) dari sungai bawah tanah: sebuah uji coba metoda VLF di sekitar Goa Bribin, Gunungkidul, Yogyakarta,†Jurnal Fisika Indonesia, VII(2), 31-42.
Sharma, P.V., 1997, “Environmental and enggineering geophysics,†Cambridge University Press.
Sharma, S.P., dan Kaikkonen, P., 1998, “Two-dimensional non-linear inversion of VLF-R data using simulated annealing,†Geophysical Journal International, 133, 649–668.
Stiefelhagen, W., dan Müller, I., 1997, â€Radio Frequency Electromagnetics (RF-EM) - extended VLF applied to hydrogeologyâ€, 59th EAGE Conference & Technical Exhibition, Geneva, Switzerland, May 26–30, p. F- 46.
Tabbagh, A., Benderitter, Y., Andrieux, P., Decriaud, J.P., dan Guerin, R., 1991â€VLF resistivity mapping and verticalisation of the electric field,†Geophysical Prospecting, 39, 1083–1097.
Turberg, P., Müller, I., dan Flury, F., 1994, â€Hydrological investigation of porous environments by RadioMagnetoTelluric-resistivity, “ Journal of Applied Geophysics, 31, 133–143.
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