the Electrical Resistivity Tomography Untuk Identifikasi Akuifer di Daerah Vulkanik (Studi Kasus: Kaliangkrik-Magelang):

Winarti Winarti; Misdiyanta Partama

Winarti Winarti Institut Teknologi Nasional Yogyakarta
Misdiyanta Partama Teknik Pertambangan ITNY

Abstract

The availability of ground water is one of the pillars of life, and must be preserved. The first step in conserving groundwater is identifying its presence. The area on the volcano's upper slopes functions as a water catchment, resulting in abundant and high-quality groundwater. The Kaliangrik area, which is located on the slopes of Mount Sumbing, is comprised of volcanic rock. The study's goal was to identify aquifers on volcanic slopes using the Electrical Resistivity Tomography (ERT) method. ERT measurements were taken over a distance of 500 meters, with electrode spacing of 30 meters, and a total n of 6. The Res2DInv software generates a 2D resistivity cross-section that describes the resistivity value laterally and vertically. Aquifers identified through ERT can serve as a basis for groundwater conservation efforts in water catchment areas. The resistivity cross section results show that the topography of the southeast is lower than that of the northwest. The resistivity range is classified into three categories: low (600 ohm meters), high (600-12,000 ohm meters), and very high (> 12,000 ohm meters). Andesite breccia has a low resistivity value as an aquifer, whereas lava has a high resistivity value. The aquifer is 20-25 meters deep (shallow) and includes a porous aquifer system. The southwest (higher topography) is the source of groundwater, so it must be conserved.

References

[1] Ashari A, Widodo E. Hidrogeomorfologi Dan Potensi Mataair Lereng Baratdaya Gunung Merbabu. Maj. Geogr. Indones. 2019; Vol. 33(1): 48-56.

[2] Manga M. On the Time Scale Characterizing Groundwater Discharge at Springs. Journal of Hydrology. 1999; 219: 56-69.

[3] Winarti, Sukiyah E, Syafri I, Nur AA. Springs Phenomena as Contacts Between Nanggulan and Old Andesite Formations at Eastern West Progo Dome, Indonesia. Int. J. GEOMATE. 2020; Vol. 19(74): 167â€“175.

[4] Asdak C. DAS sebagai Satuan Monitoring dan Evaluasi Lingkungan: Air sebagai Indikator Sentral. Seminar Sehari PERSAKI DAS.Jakarta. 1999.

[5] Irawan DE, Puradimaja DJ, Notosiswoyo S, Soemintadiredja P. Hydrogeochemistry of Volcanic Hydrogeology Based on Cluster Analysis of Mount Ciremai, West Java, Indonesia. J. Hydrol. 2009: Vol. 376(1-2): 221â€“234.

[6] Puradimaja DJ, Irawan DE, Hutasoit LM. The Influence of Hydrogeological Factors on Variation of Volcanic Spring Distribution, Spring Discharge, and Grounwater Flow Pattern. Bulletin of Geology. 2003; Vol. 35(1): 15-23.

[7] Bharti AK, Prakash A, Verma A, Singh KKK. Assessment of Hydrological Condition in Strata Associated with Old Mine Working During and Post-Monsoon Using Electrical Resistivity Tomography: a Case Study. Bull. Eng. Geol. Environ. 2021; Vol. 80(6): 5159â€“5166.

[8] Supandi S. Geotechnical Profiling of a Surface Mine Waste Dump Using 2D Wenner-Schlumberger Configuration. Open Geosci. 2021; Vol. 13(1): 335â€“344.

[9] Olayanju GM, Ayodele OS, Oni AV. Electrical Tomographic and Geotechnical Investigation of Landslide Occurrence at Agbona Hill in Okemesi, Southwestern Nigeria. Nat. Hazards. 2021; Vol. 107(2): 1965â€“1980.

[10] Suntoko H, Wicaksono AB. Identifikasi Patahan pada Batuan Sedimen Menggunakan Metode Geolistrik Konfigurasi Dipole-Dipole di Tapak RDE Serpong, Banten. J. Pengemb. Energi Nukl. 2017; Vol. 19(2): 81â€“88.

[11] Winarti, Hartono HG. 2015. Identification of Volcanic Rocks in Imogiri Yogyakarta Based on Subsurface Geologic Data. International Conference on Engineering of Tarumanegara. Jakarta. 2015; ISBN: 00-00-00-00-00: 22-23,2015

[12] Lowrie, W. Fundamentals of Geophysics. Second Edition. Cambridge: Cambridge University Press: 2007.

[13] Karunianto AJ. Analisis Kedalaman Potensi Akuifer Air Tanah Dengan Pemodelan Distribusi Tahanan Jenis Secara Inversi 2-D Desa Kompas Raya, Nanga Pinoh, Melawi, Kalimantan Barat. Eksplorium. 2013; Vol. 34(1): 11â€“22.

[14] Thanden RE, Sumadirdja HS, Richards PW. Peta Geologi Lembar magelang dan Semarang, Jawa 1: 100.000. Bandung: Direktorat Geologi, Departemen Pertambangan Republik Indonesia: 1975.