Preliminary Apparent Resistivity Mapping Using 1D Vertical Electrical Sounding in an Office Area
Ria Agustiana Putri (a*), Dr. Sri Cahyo Wahyono (a), Dr. Totok Wianto (a)

(a) Program Studi Magister Fisika, Universitas Lambung Mangkurat
Jl. Ahmad Yani KM. 36, Kota Banjarbaru 70714, Indonesia
*2421037320002[at]mhs.ulm.ac.id

Abstract

Identification of lateral variations in subsurface electrical properties can be done with an initial approach in the form of apparent resistivity mapping. This study presents an initial map of apparent resistivity in an office area in South Kalimantan. Field data were obtained from 30 1D Vertical Electrical Sounding (VES) measurement points with a Wenner configuration and electrode spacing of 5-60 m. Apparent resistivity values were then displayed on a contour map based on three selected apparent depths (z), namely z = 7.5 m, z = 17.5 m, and z = 30 m. The mapping results show variations in apparent resistivity values with apparent depth. At z = 7.5 m, it is dominated by a high apparent resistivity zone (200-500 ohm m) and a very high apparent resistivity zone (>500 ohm m). At z = 17.5 m, the zone is dominated by a medium apparent resistivity zone (100-200 ohm m) followed by a low apparent resistivity zone (50-100 ohm m) and a high resistivity zone (200-500 ohm m) that appears locally. At z = 30 m, a low apparent resistivity zone (50-100 ohm m) is widespread followed by a very low apparent resistivity zone (20-50 ohm m) as well as a medium apparent resistivity zone (100-200 ohm m) and several high apparent resistivity zones (200-500 ohm m) and very high apparent resistivity zones (>500 ohm m). These results provide an initial overview for further subsurface interpretation and hydrogeological zone analysis.

Keywords: apparent resistivity, 1D VES, Wenner configuration, apparent depth, contour mapping

Topic: Earth Physics and Space Science