//subsurface.universitaspertamina.ac.id/index.php/SUBSURFACE <p><strong>SUBSURFACE</strong> is a single-blind peer-reviewed journal focused on publication of research regarding upstream petroleum energy, geothermal energy, and mineral resources for renewable energy supporting devices. Scope of the journal covers fields of geophysics, geology, petroleum engineering, as well as information and technology related to upstream business of energy resources.</p> <p>We publish twice a year in February and September. The publication is free of charge.</p> Fakultas Teknologi Eksplorasi dan Produksi en-US SUBSURFACE <p><strong>Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)</strong></p> <p>This is a human-readable summary of (and not a substitute for) the license.</p> <p><strong>You are free to:</strong></p> <ul> <li><strong>Share</strong> — copy and redistribute the material in any medium or format</li> <li><strong>Adapt</strong> — remix, transform, and build upon the material</li> </ul> <p>The licensor cannot revoke these freedoms as long as you follow the license terms.</p> <p><strong>Under the following terms:</strong></p> <p>Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.</p> <ul> <li><strong>NonCommercia</strong>l — You may not use the material for commercial purposes.</li> <li><strong>ShareAlike</strong> — If you remix, transform, or build upon the material, you must distribute your contributions under the same license as the original.</li> <li><strong>No additional restrictions</strong> — You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.</li> </ul> <p><strong>Notices:</strong></p> <ul> <li>You do not have to comply with the license for elements of the material in the public domain or where your use is permitted by an applicable exception or limitation.</li> <li>No warranties are given. The license may not give you all of the permissions necessary for your intended use. For example, other rights such as publicity, privacy, or moral rights may limit how you use the material.</li> </ul> //subsurface.universitaspertamina.ac.id/index.php/SUBSURFACE/article/view/47 <p>Daerah penelitian berada di Situ Babakan, Bantarkambing, Bogor yang termasuk kedalam area Cekungan Air Tanah (CAT) Jakarta dan berada pada satuan kipas aluvium yang berumur Pleistosen. Daerah penelitian ini memiliki sungai dengan pola aliran dendritik serta kemiringan pada lereng yang cukup landai. Diketahui dari hasil uji bor tangan atau handbor yang telah dilakukan, bahwa pada kedalaman 0-0,6 meter area Situ Babakan merupakan lapisan pasiran berwarna cokelat dengan plastisitas yang tinggi (jenuh air) yang bertindak sebagai akuifer, sedangkan pada kedalaman 0.6-5.2 meter merupakan lapisan tuf halus berwarna cokelat dengan plastisitas yang tinggi bertindak sebagai akuiklud. Muka air tanah disekitar Situ Babakan memiliki kedalaman berkisar 2-4 meter yang berarah aliran menuju arah barat serta kualitas air tanah yang dilihat dari hasil pemeriksaan kimia memiliki kandungan Fe dan Mn cukup tinggi dan apabila hasil dari pemeriksaan mikrobiologi menunjukkan bahwa air terkontaminasi oleh bakteri E.coli dan total coliform. Hasil pemodelan yang dilakukan menunjukkan bahwa Situ Babakan akan mengalami keruntuhan di bagian tanggul hilir dengan kondisi MDE (<em>Maximum Design Earthquake</em>) yaitu FK sebesar 1.211, sedangkan kondisi OBE (<em>Operating Based Earthquake</em>) memiliki nilai FK sebesar 1.470 di mana nilai FK tersebut menunjukkan bahwa lereng bagian hilir cenderung rentan. Banjir yang diakibatkan oleh keruntuhan Situ Babakan mengakibatkan 19.60 Ha kerusakan pada sektor perkebunan, 65.30 Ha sektor persawahan, dan 9.30 Ha permukiman dan sekitar 870 orang perlu dievakuasi dari 3 (tiga) desa antara lain Desa Bantarjaya, Desa Bantarsari, dan Desa Gimulang yang dilewati oleh banjir. Upaya penanganan dini yang dapat dilakukan oleh masyarakat adalah pelatihan mitigasi, mempersiapkan tas darurat serta mengetahui informasi-informasi penting terkait kondisi prabencana, saat banjir terjadi, dan pascabencana. Mitigasi struktural dilakukan untuk dapat dilakukan pemeliharaan dan evaluasi untuk infrastruktur pada tubuh bendungan sehingga dapat meminimalisasi terjadinya keruntuhan.</p> Galih Dhela Pradina Dhela Imam Priyono Ahmad Taufiq Copyright (c) 2024 SUBSURFACE https://creativecommons.org/licenses/by-nc-sa/4.0 2024-02-29 2024-02-29 2 01 1 15 //subsurface.universitaspertamina.ac.id/index.php/SUBSURFACE/article/view/164 <p>The Sulawesi region has a high level of earthquake vulnerability because it is bounded by two major plates, the Eurasian plate and the Indo-Australian plate, which leads to several paths and faults scattered throughout the region, including the volcanoes in North Sulawesi Province, the Gorontalo fault in Gorontalo Province, and the Palu-Koro fault in Central Sulawesi Province. In North Sulawesi, Gorontalo, and Central Sulawesi, soil characteristics were studied utilizing the Horizontal and Vertical Spectral Ratio (HVSR) approach. The dominant frequency (f0), the amplification factor (A0), the seismic vulnerability index (Kg), and the shear wave velocity at a depth of 30 m (Vs30) were all measured in this study. According to the findings of this study, the distribution of dominant frequency values ranged from 0.6 to 17 Hz, the amplification factor ranged from 2.2 to 8.4, the seismic vulnerability index ranged from 0.2 to 41, and the shear wave velocity at the depth of 30 meters (Vs30) ranged from 226 to 519 m/s.</p> Ahmad Naufal Fadhil Iktri Madrinovella Bayu Pranata Elisabet Anggun Pramesthi Copyright (c) 2024 SUBSURFACE https://creativecommons.org/licenses/by-nc-sa/4.0 2024-02-29 2024-02-29 2 01 16 25 //subsurface.universitaspertamina.ac.id/index.php/SUBSURFACE/article/view/110 <p>The gravity method is a geophysical exploration method based on measuring differences in gravity values caused by variations in density laterally under the earth's surface. Mapping using the gravity method can be utilized to obtain a representation of subsurface geological conditions based on density variations. In this research, the inversion process of subsurface models in geothermal areas is carried out, especially in the case of enhanced geothermal system development. Processing of gravity data is <br>done by utilizing Python-based programming language to grid data and interpolation with ordinary kriging and spline interpolation methods. The results of the data interpolation will be compared to obtaining the best model based on the distribution of measurement points that can be used in Utah FORGE data, USA. The 3D gravity inversion process is performed by utilizing the discretize library and SimPEG to provide an overview of the source of subsurface anomalies with gravity data. Modeling was performed using synthetic data as a test of the inversion process and Utah FORGE field CBA data. The inversion results will be interpreted by correlating geological data to validate the interpretation results.</p> TRY ANY SPRYANY PANGGABEAN Dicky Ahmad Zaky Copyright (c) 2024 SUBSURFACE https://creativecommons.org/licenses/by-nc-sa/4.0 2024-11-14 2024-11-14 2 01 26 36