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Coastal Hydrogeological Model in the Iron Ore Prospect Area of Widarapayung Coastal, Cilacap Regency Based on 2D-Resistivity Data Sehah Sehah; Sukmaji Anom Raharjo; Abdullah Nur Aziz
Jurnal Penelitian Fisika dan Aplikasinya (JPFA) Vol. 8 No. 2 (2018)
Publisher : Universitas Negeri Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26740/jpfa.v8n2.p71-83

Abstract

The coastal hydrogeological model of iron ore prospect area in Widarapayung coastal, Cilacap Regency, has been designed and performed based on the 2D-resistivity data. The background of this research is potentiality of iron sand in this area and its prospect to be mined. Mining activities in large-scale may lead into surface decreasing, triggering damage to the aquifer, abrasion, and saltwater intrusion in the coastal area. The acquisition of 2D-resistivity data has been performed on five trajectories including of WP-01 up to WP-05. Based on the modeling results, it can be concluded that the sub-surface rocks resistivity profile consists of WP-01 with the values of 1.93-114.00 Ωm; WP-02 with the values of 3.67-121.00 Ωm; WP-03 with the values of 3.86-78.40 Ωm; WP-04 with the values of 1.79-100.00 Ωm; and WP-05 with the values of 2.61-86.20 Ωm. After interpretation, it is found that the hydrogeological profile of sub-surface rocks consists of sand inserted with gravels (topsoil); sand containing iron ore granules inserted with silt (topsoil and shallow aquifer); clayey sand (semi-aquifer layer); sandy clay (semi-impermeable layer); and sand (deep aquifer which is intruded by salt water). Based on the analysis, the sand containing iron ore is part of the shallow aquifer, so the mining activities of iron sand is potential to damage and reduce aquifer function in storing and flowing the groundwater in the research area.
Identifikasi Lapisan Pembawa Mineral Emas dengan Metode Resistivitas dan Induksi Polarisasi di Desa Paningkaban Kecamatan Gumelar Kabupaten Banyumas Jawa Tengah Nandi Maulani Nasruddin; Aditya Verry Saputra; Mia Durrotun Nafisah; Sehah Sehah
Jurnal Fisika FLUX Vol 17, No 1 (2020): Jurnal Fisika Flux: Jurnal Ilmiah Fisika FMIPA Universitas Lambung Mangkurat
Publisher : Lambung Mangkurat University Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (3503.186 KB) | DOI: 10.20527/flux.v17i1.6602

Abstract

The research has been done in the Paningkaban village, Gumelar District, Banyumas Regency, Central Java Province. This research aims to identify technically the presence of gold mineral distribution using the method of geoelectricity-resistivity and induced polarization (IP), to interpret the obtained resistivity and chargeability data from the research area, to determine the subsurface structure model in the reasearch area, and find out the potential of gold in the research area i.e Paningkaban. The method in this research includes field data acquisition, data processing, and data interpretation. The acquisition uses a syscal resistivitymeter tools by stretching 200 meters of cable on each track that has been connected to the electrode and porous pot. The results obtained from the acquisition are primary data which are still in the form of voltages, currents, and apparent chargeability values. Based on this data, the processing is carried out to obtain the resistivity and chargeability profiles so that can be interpreted and correlated. The correlation between the  resistivity and chargeability data was carried out to identify the gold mineralization zone in two dimensions. The presence of gold mineralization is characterized by the emergence of rocks with a low resistivity value and high chargeability because mineralization in the geological area is seen in quartz veins. Quartz veins are common features of many deposits and are indicative of the presence of mineralization, especially gold. Based on the results of the interpretation, the subsurface rock which contain gold minerals are found on each line, with resistivity values ranging from 4,25 – 17,3 Ωm and the chargeability value ranges from 26,4 – 226 msec. These rocks which are estimated to contain gold minerals are the sandy clay.
Investigasi Intrusi Air Asin di Kawasan Prospek Bijih Besi Pesisir Nusawungu Kabupaten Cilacap Jawa Tengah Berdasarkan Profil Resistivitas-2D Sehah Sehah; Zaroh Irayani; Sukma Sewiji
Jurnal Fisika FLUX Vol 15, No 2 (2018): Jurnal Fisika Flux: Jurnal Ilmiah Fisika FMIPA Universitas Lambung Mangkurat
Publisher : Lambung Mangkurat University Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (159.232 KB) | DOI: 10.20527/flux.v15i2.5530

Abstract

ABSTRACT−Investigation of saltwater intrusion in Nusawungu Coastal area of Cilacap Regency based on the 2D-resistivity data has been done in April – Juni 2018. The resistivity data acquisition has been carried out using Wenner's configuration on four locations covering of the NWT-01, NWT-02, NWT-03, and NWT-04 with a length as 200 meters. The obtained result is the 2D-resistivity profile of subsurface rocks for each trajectory with a depth of about 30 meters. The rock resistivity values which obtained for each trajectory consists of the NWT-01 is 2.30 – 103.00 Ωm; the NWT-02 is 3.65 – 54.30 Ωm; the NWT-03 is 0.96 – 43.20 Ωm; and the NWT-04 is 2.33 – 70.80 Ωm. Based on the interpretation results, the deep aquifer in each trajectory with a resistivity value of 0.96 - 6.81 Ωm are estimated to be intruded by saltwater, while the shallow aquifers have not been significantly intruded by saltwater. Based on the testing results of the electrical conductivity (DHL) of several water samples taken from some wells around the NWT-01 to NWT-04 trajectory, it is known that all of the water is freshwater. Some well water samples have a rather high electrical conductivity value, such as the well A on the NWT-01 with a value of 740.0 μSi/cm and the well C on the NWT-03 with a value of 894.67 μSi/cm. This is thought to be due to the relatively high salt mineral content in the aquifer rocks.
Inovasi pemanfaatan peta anomali pseudogravitasi untuk interpretasi pola sebaran batuan andesit masif di desa Candiwulan kecamatan Kutasari kabupaten Purbalingga dan sekitarnya Sehah Sehah; Sukmaji Anom Raharjo; Urip Nurwijayanto Prabowo
Jurnal Teras Fisika: Teori, Modeling, dan Aplikasi Fisika Vol 3 No 1 (2020): Jurnal Teras Fisika: Teori, Modeling, dan Aplikasi Fisika
Publisher : Universitas Jenderal Soedirman

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20884/1.jtf.2020.3.1.2348

Abstract

Pemanfaatan peta anomali pseudogravitasi untuk menginterpretasi sebaran batuan andesit di Desa Candiwulan Kecamatan Kutasari Kabupaten Purbalingga dan sekitarnya telah dilakukan. Penelitian dilakukan pada bulan April hingga September 2019. Bahan dan peralatan yang diperlukan terdiri atas data anomali magnetik total, personal computer (PC), dan beberapa perangkat lunak seperti Fortran 77, Surfer 10, dan Arc-GIS 3.0. Jumlah data anomali magnetik total yang diperoleh adalah 142 data yang membentang pada posisi geografis 109,2788° – 109,3072° BT dan 7,3032° – 7,3319° LS dengan nilai berkisar -1,376.79 – 2,037.26 nT. Data anomali magnetik total selanjutnya diolah melalui beberapa tahap sehingga diperoleh data anomali magnetik lokal dengan nilai berkisar -1.238,13 – 1.892,4 nT. Pemfilteran terhadap data anomali magnetik lokal dilakukan untuk mereduksi efek-efek magnetik di permukaan sehingga diperoleh data anomali magnetik lokal baru dengan nilai berkisar -309.321 – 770.88 nT. Untuk melokalisir sumber anomali bawah permukaan, data anomali magnetik lokal baik sebelum maupun setelah difilter ditransformasi menjadi data anomali pseudogravitasi. Untuk data anomali magnetik sebelum difilter, diperoleh data anomali pseudogravitasi berkisar-75,992 – 119,498 mGal. Sedangkan untuk data anomali magnetik setelah difilter, diperoleh data anomali pseudogravitasi berkisar -27,815 – 41,087 mGal. Hasil interpretasi terhadap kedua peta anomali pseudogravitasi mengindikasikan adanya sumber anomali dangkal yang tersebar di bagian barat hingga barat laut daerah penelitian, dimana sumber anomali tersebut mengarah relatif ke bawah di bagian barat. Sumber anomali tersebut diinterpretasi sebagai batuan beku andesit yang masif
ANALISIS ZONA LEMAH (AMBLESAN) DI KAWASAN JALAN RAYA GUNUNG TUGEL KABUPATEN BANYUMAS BERDASARKAN SURVEI GEOLISTRIK KONFIGURASI WENNER Syukron makmur; Sehah Sehah; Sugito Sugito
Techno (Jurnal Fakultas Teknik, Universitas Muhammadiyah Purwokerto) Vol 17, No 2 (2016): Techno Volume 17 No 2, Oktober 2016
Publisher : Universitas Muhammadiyah Purwokerto

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30595/techno.v17i2.1404

Abstract

The geo-electrical survey with wenner configuration has been done in the Gunung Tugel street area, Village of Kedungrandu, District of Patikraja, Regency of Banyumas. The purposes of the research is to interpret the subsurface rocks lithology based on the resistivity values, analyze the existence of the weak zone that spread beneath of the subsidence zone surface on the highway, explore the existence of others weak zones that located outside of the existing subsidence zone, and explain the causes of the subsidence happened in this area. Modeling and interpretation of the subsurface rock resistivity values is done using the Res2dinv 3.54 and Surfer 10 software. The results of the modeling and interpretation on the resistivity values at line GT-L01 and GT-L02 shows subsurface rocks structure model in the form of the finely sand with a resistivity values of 0.90 to 3.00 Ωm, marl rock with a resistivity values of 3.00 - 10.00 Ωm, and calcareous sandstones with a resistivity values of 10.00 to 26.00 Ωm. Beside the results of the research also show a weak zone beneath of the subsidence zone surface and found some others weak zones outside of the subsidence zone. The weak zone in this area is interpreted as fine sandstone that softly and not compactly. While the others weak zones that located outside of the subsidence zone are indicated potentially to be the cause of a new subsidence on the highway. The subsidence that happened on the highway is estimated because the rocks blocks in the weak zone are unable to support changes in the layer structure above it, in the form of marl, as a result of weight force and pressure resulted by most heavy-weighed vehicle which always going through on this highway.
Interpretation of 1D-Resistivity Data to Describe the Aquifer Model in the Serayu Watershed Area of Somagede Village, Somagede District, Banyumas Regency Sehah Sehah; Hartono Hartono; Zaroh Irayani; Urip Nurwijayanto Prabowo; Fajar Apriyanto; Desty Maharani Sagita; Dwi Purnamasari
Jurnal Geologi dan Sumberdaya Mineral Vol. 22 No. 2 (2021): JURNAL GEOLOGI DAN SUMBERDAYA MINERAL
Publisher : Pusat Survei Geologi

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33332/jgsm.geologi.v22i2.567

Abstract

Acquisition of resistivity data using the Schlumberger configuration has been carried out in the Serayu watershed area of Somagede Village, Somagede District, Banyumas Regency. The purpose of this research was to describe a groundwater aquifer model based on the interpretation of 1D-resistivity data. The research results are resistivity logs of subsurface rock distributed over seven sounding points with resistivity values ranging from 2.24-192.78 m. The sounding points are located at positions of 7°31′28.55″ and 109°19′8.65″ (Sch-1) to 7°31′18.79″ and 109°19′21.45″ (Sch-7). The interpretation of the resistivity logs has resulted in a lithology log at each sounding point. Based on the interpretation, the lithology of the research area is composed of topsoil (42.85-85.13 m), sandy clay which partly slightly wet (7.08-17.18m), sandy clay inserted with gravel (22.44-31.70 m), sand, gravel, and pebble, with various consolidated (22.16-192.78m), sand inserted by gravel (6.77m), alternating sandstone and claystone, some of which are alternated with marl and tuff (8.71-21.99m), and sandstones with various porosity (3.25-8.76m). Shallow aquifers are interpreted to exist in sand inserted by gravel layer (13.23-27.67 m) at the sounding point of Sch-2 where the potential is quite good. While deep aquifers are estimated to be present in the sandstone layer with various porosity (> 46.67 m) at all sounding points with very good potential.Keywords: 1D-resistivity, Serayu watershed, resistivity log, aquifer, Somagede Village.