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Abstract. It has been conducted a geo-electrical resistivity survey at geothermal area of Ie Jue, Aceh Besar. The survey aims to measure resistivity value in the area. It is expected that the values of resistivity will image the subsurface structure in the area. In addition geological features in the area are shown after we process it. The data acquisition in this study was acquired using a SuperSting R8/IP resistivitymeter and its data processing using EarthImager 2D software to get the image of resistivity pseudosection. The two lines of measurement crossed the surface geothermal manifestation. Each line has 330 m in length, and 56 electrodes with electrode space of 6 m. The result of resistivity pseudosection model interpreted based on geological condition and observation in the area. Resistivity pseudosection model shows the study is water-saturated (<64.0 Ωm) to a depth of ±65 m and a highly conductive zone (0.6-3.5 Ωm) with a thickness of 30-50 m. This conductive layers below the embodied surface at a distance of 158-160 m on the IJ-Y1 line and at a range of 130-185 m on the IJ-Y2 line. This conductive zone is indicated as a weak zone where geothermal fluids are transported to the surface.

Groundwater availability is the main concern in a developing region such as Weh Island, Aceh. To locate groundwater resources, vertical electrical sounding (VES) was used to identify subsurface profiles. The study area is located on a volcanic island. The lithology consists of volcanic rocks as andesite lava and pyroclastic rocks as lapily-tuff until breccia. VES method was carried out in 4 measurement points using the Schlumberger array. The resistivity value used to identify subsurface lithology. The top layer of alluvium and weathered lava have resistivity ranges from 14.3 Ωm to 17.7 Ωm with thickness varies from 0 m – 17.4 m. It is followed by andesite resistivity ranges from 17.3 Ωm to 18.2 Ωm with averages thickness is 17.4 m – 35.2 m. Finally, the bottom layer is filled by breccia-tuff with resistivity value from 5.5 Ωm to 7.3 Ωm. The physical properties of some related rocks allow water accumulation to their bodies. The current polarization indicates water content in the pore space of breecia at the study area which polarization point is identified as the water table.