Contribution of Resistivity Properties in Estimating Hydraulic Conductivity in Ciremai Volcanic Deposits

The hydraulic parameters of porous media, such as porosity (φ) and hydraulic conductivity (K), are the most important factors for planning and managing water exploitation from aquifers. This study aims to estimate the hydraulic conductivity parameters using the geoelectric method on volcanic deposits on the northern slope of Mount Ciremai. For this purpose, four data types were used to estimate K and φ, including lithological profiles, water table, groundwater quality, pumping test data, and vertical electrical sounding (VES). Based on Archie's law and Kozeny's equation, we get the alpha (α) values and cementation factor (m) from which the median values of α = 1.01 and m = 1.36 represent the studied aquifer.  The porosity (φ) of the aquifer varies from 0.097 to 0.187 with an average of 0.141 and is spatially related to the hydraulic conductivity (kgm), which varies from 4.97 × 10-6 to 6.75 × 10-5 m/s after the application of Kozeny's equation. The hydraulic conductivity (Kp) calculated from the pumping tests varies from 9.07 × 10-6 to 1.06 × 10-4 m/s and is strongly correlated (r = 0.87). Furthermore, a relation between resistivity and hydraulic conductivity was established for the studied aquifer to estimate these parameters in sites lacking data

Resistivity Data Modeling for Subsurface Volcanostratigraphy Construction of Cibadak Sub-Watershed, Bogor, West Java, Indonesia.

In Mt. Salak, there are six volcanic facies divided by eruption time seen from geomorphology data analysis and to identified the subsurface layer DC Resistivity method is applied. Beside resistivity, geostatistical parameters also influence the result model interpretation, so for obtain best model correlation parameters such as tilting, surfacing, variogram, grid method, and logarithmic distribution is applied. Using 18 points of acquisition data subsurface model is produce and then section model made to describe vertical resistivity distribution then correlated with facies lithology model. Based on that, produce three facies resistivity type namely: 0 – 100 Ohm.m (Low Resistivity Value) Interpreted as pyroclastic material composed as tuff and breccia that lies under lava. 100 – 300 Ohm.m (Medium Resistivity Value) Interpreted as breccia lithology type. Harder that pyroclastic material due to by this product is avalanches of lava. And >300 Ohm.m (High Resistivity Value) Interpreted as lava lithology that lies at high elevation and the hardest lithology in this area. From the model, pyroclastic layer that is modeled found at low elevation and based on the direction it described as oldest facies layer, but at the bottom of this layer lies high resistivity value that unknown product. It can be Mt. Pangrango product due to at low elevation predicted as combine area product from product of Mt. Salak and Pangrango. High resistivity value show lava lithology and lava facies located in high elevation and medium resistivity describe breccia lithology as avalanche product of lava (youngest pyroclastic facies) and found at 500 – 100 meters msl

Karakteristik Sistem Akuifer pada Formasi Endapan Permukaan di Daerah Sei Mati Kota Medan Berdasarkan Metode Geolistrik 2D

Daerah Sei mati memiliki potensi sumber daya air yang baik, dikarenakan daerah yang termasuk Cekungan Air tanah Medan. Penelitian ini bertujuan untuk mengetahui potensi airtanah dengan menggunakan metode geolistrik 2D dengan konfigurasi wenner-schulumberger. Hasil penelitian menunjukan terdapat 2 lapisan akuifer yaitu akuifer dangkal dan dalam. Lapisan akifer dangkal berada pada kedalaman berkisar antara 0 – 50 meter, membentuk pola channel-channel yang menunjukan endapan fluvial dengan nilai tahanan jenis antara 5 Ω.m - 10 Ω.m, dengan litologi pasir lempungan, namun dibeberapa tempat dijumpai channel lempung yang bersifat akuiklud (tidak dapat menyimpan air). Lapisan akuifer dalam muncul pada kedalaman 50 meter hingga 100 meter dengan litologi pasir

Pendugaan Akifer Airtanah dengan Metode Geolistrik Konfigurasi Schlumberger di Lereng Utara Gunungapi Tangkubanparahu

Airtanah sangat diperlukan dan meningkatnya jumlah penduduk akan menyebabkan pengurangan cadangan airtanah yang tersedia. Gunung Tangkubanparahu merupakan daerah endapan vulkanik yang memiliki potensi sistem akuifer airtanah yang baik. Tujuan penelitian ini adalah untuk mengetahui potensi airtanah dari sistem akuifer vulkanik berdasarkan pengamatan geologi dan pengukuran geolistrik 1D sebanyak 100 titik. Hasil penelitian menunjukkan empat kelompok nilai resistivitas yang merepresentasikan kondisi geologi bawah permukaan. Kelompok pertama mempunyai nilai 0-100 ohm.m, berupa kelompok batuan piroklastik yang tercampur tanah. Kelompok kedua mempunyai nilai resitivitas 101-250 ohm.m, berupa kelompok batuan perselingan antara pasir tufan dan tuf kasar. Kelompok ketiga mempunyai nilai 251-600 ohm.m, berupa kelompok batuan breksi. Kelompok keempat  mempunyai nilai resistivitas >600 ohm.m, berupa kelompok batuan aliran lava. Sistem airtanah yang dapat diasumsikan sebagai akifer tersebar merata pada kedalaman 50 m, 75 m, dan 100 m berupa kelompok batuan tuf.Groundwater is the primary source of water and the increase in population will cause an decrease in groundwater reserves. Mt.Tangkubanparahu is a volcanic deposition area that has high potential groundwater aquifer systems. The purpose of this study was to determine the groundwater potential of the volcanic aquifer system based on geology mapping and 1D geoelectric measurements at 100 stations. The results indicated four groups of resistivity values, which represent subsurface geological conditions. The first group has a resistivity value of 0-100 ohms.m in the form of pyroclastic rocks. The second group has a resistivity value of 101-250 ohms.m in the form sand tuff and coarse tuff. The third group has a value of 251-600 ohm.m in the form of breccia rocks. And the fourth group has resistivity values> 600 ohms in the form of lava flow rock groups. In the groundwater system, the layer that can be assumed as aquifer is evenly distributed at depths of 50 m, 75 m, and 100 m in the form of tuff groups. 

Sistem Akuifer Air Tanah Daerah Sukamoro Kabupaten Banyuasin - Sumatera Selatan

Studi sistem akuifer hidrogeologi sangat penting untuk dilakukan dalam rangka mengidentifikasi kondisi geologi dan hidrogeologi. Lokasi daerah penelitian termasuk ke dalam daerah bukan cekungan air tanah, tetapi kondisi visual di lapangan menunjukkan penduduk sekitar banyak memanfaatkan air tanah cukup besar. Metode yang digunakan berupa penyelidikan geologi, geolistrik 2-D konfigurasi Wenner – Schlumberger dan hidrogeologi. Tujuan dari penelitian ini yaitu mengetahui sistem akuifer  daerah Sukamoro.  Di daerah Sukamoro terdapat dua sistem akuifer, yaitu pada endapan rawa (satuan lanau) berupa sistem dengan aliran antar butir; merupakan sistem airtanah tidak tertekan, dengan nilai TDS yang acak dengan nilai resistivitas di bawah 40 Ohm meter, berada pada bagian Selatan daerah penyelidikan. Pada satuan perselingan batupasir dengan batulempung yang memiliki sistem akuifer dengan aliran melalui ruang antar butir dan rekahan, merupakan sistem airtanah tidak tertekan dan tertekan,  dengan nilai TDS  antara 80-240 mg/L dan di bawah 80 mg/L, dengan nilai resistivitas 41-450 Ohm mete