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INVESTIGATION OF SUBSURFACE GROUNDWATER USING THE VES METHOD AROUND DENDAM LAKE, BENGKULU CITY, INDONESIA Maghribi, Faritz Bagda; Refrizon, Refrizon; Suhendra, Suhendra; Fadli, Darmawan Ikhlas; Halauddin; Idris, Beni Syakban; Johan, Henny; Putriani, Eli
Spektra: Jurnal Fisika dan Aplikasinya Vol. 8 No. 2 (2023): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 8 Issue 2, August 2023
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.082.04

Abstract

Concerns have been raised over the availability of water in the Dendam Lake neighborhood of Bengkulu City and the areas surrounding it. The location is characterized by a number of unsuccessful water wells. These issues are the direct and indirect results of the geological formations that are present in the region, specifically Aluvium (which consists of boulders, clasts, sand, silt, mud, and clay). A MAE X-612 EM resistivity meter was utilized in order to get a total of twenty Vertical Electric Sounding (VES) measurement points. Using the software programs Progress and Surfer, the data that was gathered was plotted on a two-log graph. The geoelectric layer and layer parameter maps that were made were prepared with the use of quantitative and qualitative interpretations. It was determined that there were between three and five geoelectric layers. It has been demonstrated that the resistivity of the subsurface shallow groundwater zone ranges from 10 to 20 Ωm at a depth of 4 to 15 meters. According to the findings of this research project, employing the VES geo-electrical exploration approach is likely capable of effectively outlining the subsurface and shallow groundwater. In addition, there is no information available regarding the precise depth of the groundwater table in the region. On the other hand, the underground groundwater at this location has a depth that is shallower than the norm.
Mapping Landslide Vulnerability using Machine Learning Approach along the Taba Penanjung-Kepahiang Road, Bengkulu Province Abrar, Camelia Batun; Lubis, Ashar Muda; Fadli, Darmawan Ikhlas; Akbar, Arya J; Samdara, Rida
Geoplanning: Journal of Geomatics and Planning Vol 11, No 1 (2024)
Publisher : Department of Urban and Regional Planning, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/geoplanning.11.1.43-56

Abstract

Landslides occur when masses of rock, debris or soil move due to various factors and processes that cause land movement. The Taba Penanjung-Kepahiang route is one of the areas in Bengkulu Province that is highly prone to landslides. This causeway is the only fastest land route connecting the Bengkulu-Kepahiang area. In recent years, the road area has often been cut off due to landslides and fallen trees, which have caused road access to be cut off and obstructed and claimed lives. This study uses a Machine Learning (ML) and GIS approach with Variable Frequency Ratio using 16 independent factors obtained from the spatial database and DEM, which correlate with landslide events. This research aims to gain an in-depth understanding of the factors that cause landslides. In addition, the research focus is the development of a Disaster Mitigation Model to design and implement effective strategies to reduce the risk and impact of landslide disasters through in-depth analysis The dependent factor is the location of the landslide from the historical landslide area for the last five years, with a distribution of 70/30%. Furthermore, frequency ratio is used to analyze the correlation between conditioning factors and historical landslides. Then, the independent and dependent factors were normalized to create a landslide susceptibility map. Frequency Ratio (FR) indicates the likelihood of an event occurring, with drainage density (FR= 0.69), shear wave velocity (Vs30) (FR= 0.66), slope (FR= 0.60), and rainfall (FR= 0.55).  The output of the processed data is in the table below.
Studi Mikrozonasi Kerentanan Seismik dan Bangunan Bertingkat Menggunakan Metode HVSR (Horizontal to Vertical Spectral Ratio) di Kabupaten Bengkulu Selatan Novtrisa, Indri; Mase, Lindung Zalbuin; Refrizon, Refrizon; Misliniyati, Rena; Amri, Khairul; Hadi, Arif Ismul; Fadli, Darmawan Ikhlas
Jurnal Fisika Flux: Jurnal Ilmiah Fisika FMIPA Universitas Lambung Mangkurat Vol 21, No 3 (2024): 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 | DOI: 10.20527/flux.v21i3.19616

Abstract

Mikrozonasi seismik merupakan proses pemetaan untuk memprediksi respon tanah terhadap guncangan seismik yang dapat digunakan sebagai acuan mitigasi bencana dan pembangunan yang akan dilakukan di Kabupaten Bengkulu Selatan. Penelitian ini menggunakan data shapefile peta administrasi dan data mikrotremor sebanyak 69 titik. Data mikrotremor kemudian diolah menggunakan metode HVSR (Horizontal to Vertical Spectral Ratio) untuk mendapatkan kurva HVSR. Pengolahan data ini menghasilkan nilai faktor amplifikasi ( ) pada rentang 1,17 – 4,07, nilai frekuensi natural ( ) antara 0,25 Hz – 14,40 Hz, indeks kerentanan seismik (Kg) antara 0,26 – 11,78,  dan nilai periode dominan ( ) antara 0,07 s – 3,86 s. Parameter ini selanjutnya digunakan untuk membuat peta sebaran yang akan memberikan gambaran mengenai distribusi spasialnya. Selain itu, potensi bangunan yang rentan terhadap bencana seismik dengan ketinggian 1 hingga 2 lantai teridentifikasi di Kecamatan Pino Raya dan Kecamatan Kota Manna, sedangkan bangunan dengan ketinggian 1 hingga 4 lantai berada di Kecamatan Pasar Manna.. Berdasarkan nilai-nilai parameter tersebut, dapat disimpulkan bahwa lokasi penelitian masuk ke dalam kategori zona rendah terhadap getaran gempa bumi. Hasil penelitian ini dapat digunakan dalam perencanaan mitigasi bencana, khususnya dalam upaya peningkatan ketahanan bangunan di wilayah yang diteliti.
MICROZONATION ANALYSIS IN MANNA CITY & PASAR MANNA SUBDISTRICTS UTILIZING MICROTREMOR DATA, SOUTH BENGKULU REGENCY Refrizon, Refrizon; Fadli, Darmawan Ikhlas; Triutami, Olga; Putri, Aisyah Cindy Phylia; Rahmawati, Nurul Ilmi
Indonesian Physical Review Vol. 7 No. 1 (2024)
Publisher : Universitas Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/ipr.v7i1.252

Abstract

South Bengkulu is prone to earthquakes because it is located on the Great Sumatran Fault. Apart from that, it is also influenced by the activity of the Musi and Manna segments, so that besides being influenced by the two active tectonic plates it is also influenced by the local segment. This research is located in Manna City and Manna Market, which is mostly inhabited by people and is the capital of South Bengkulu. In connection with infrastructure development, it is necessary to know the condition of the soil layers to minimize the risk of building damage due to earthquakes. This research aims to analyze earthquake-prone areas based on dominant frequency parameters, soil amplification, seismic vulnerability index and sediment layer thickness (h). Research data comes from microtremor measurements at 60 measuring station points in Manna City and Manna Market. The tool used is a Short Period Portable Seismometer Model Gemini 2 SN-1405. This microtremor data is processed using the Horizontal to Vertical Spectral Ratio (HVSR) method. The results of data processing show that the research area has the lowest dominant frequency of 3.95 Hz and the highest of 49.71 Hz. The ground vibration amplification value is classified as small to medium, the lowest is 1.3 and the highest is 5.19. The lowest earthquake vulnerability index was 0.18 cm2/s and the highest was 2.24 cm2/s. The smallest sediment thickness was 3.77 meters and the thickest was 47.48 meters. From the results of the calculation of the seismic vulnerability index in Kota Manna and Pasar Manna Districts, the seismic vulnerability index value is relatively small, in accordance with the amplification factor and the thickness of the sediment layer. Based on this research, although Manna City and Manna Market are often shaken by earthquakes, the earthquake vibrations experience small amplification.
Coastal vulnerability assessment using electrical resistivity tomography in Padang Betuah, Central Bengkulu Suhendra, Suhendra; Halauddin, Halauddin; Lizalidiawati, Lizalidiawati; Sinaga, Jesika Erni Elfrita; Fadli, Darmawan Ikhlas; Idris, Beni Syakban
International Journal of Advances in Applied Sciences Vol 12, No 4: December 2023
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijaas.v12.i4.pp301-308

Abstract

Abrasion disaster in the coastal area of Padang Betuah Beach has a high level of abrasion in Central Bengkulu. The local community utilizes abrasion in the coastal area as a tourist attraction and becomes local revenue in the research location. The location that becomes a tourist attraction is decreasing because the coastal area’s land has been abraded. After conducting research using the electrical resistivity tomography (ERT) method in 2D and 3D, it was found that claystone dominated the coastal area at the research location with a resistivity value of 16-200 Ωm at a depth of 15-20 m. The coastal area in Padang Betuah Beach is composed of clay shale rocks (207-220 Ωm), and the depth is 2-14.8 m. Clay shale rocks are not abraded in stones with resistivity values >250 Ωm. This is caused by clay shale, which has low porosity, so it has a compact rock density. Seawater is identified at a depth of 21-63 m with a resistivity value of 2.225-10.2 Ωm. The depth of seawater determined follows the average height of the cliffs in the research location. The abrasion process can be slowed down by making jetties, water breakers, and mangrove cultivation.
Micro-Zonation Mapping of Landslide Potential Using Statistical Weighting Method of Analytical Hierarchy Process (AHP) in South Bengkulu–Lahat Road for Disaster Mitigation Hadi, Arif Ismul; Harlianto, Budi; Hudayat, Nurul; Farid, M.; Virgo, Frinsyah; Fadli, Darmawan Ikhlas; Humairah, Fadillah
Jurnal Penelitian Pendidikan IPA Vol 11 No 2 (2025): February
Publisher : Postgraduate, University of Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/jppipa.v11i2.9915

Abstract

The research objective was to identify areas with high, medium, and low potential for landslides by micro-zonation on the South Bengkulu–Lahat road, map areas with potential for landslides based on the parameters that contribute to causing landslides using the AHP method, and determine the parameters for landslides, the dominant parameter affecting the occurrence of landslides in the study area. To achieve the research objectives, all parameters that cause landslides obtained at measurement points are then overlaid using the AHP statistical weighting method. The results showed that the area along the South Bengkulu–Lahat road had been identified microzoning high, medium, and low landslide potentials based on statistical weighting from parameters were obtained at the measurement points. For areas with high landslide potential, caution should be exercised, especially during the rainy season with high intensity and long duration.
Coastal Abrasion Vulnerability of the Southern Seluma Regency, Bengkulu, Based on Seismic Properties and Parameters Elasticity Natasya, Indah Dwi; Refrizon, Refrizon; Hadi, Arif Ismul; Fadli, Darmawan Ikhlas; Larang, Miranda Puspa; Putri, Elona Gita Gatra; Maghribi, Faritz Bagda; Sumanjaya, Erlan
Indonesian Journal on Geoscience Vol. 12 No. 1 (2025)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17014/ijog.12.1.133-144

Abstract

Geophysical investigations were conducted in the coastal area of Seluma Regency using Multi-Channel Analysis of Surface Waves (MASW) to determine subsurface geology, material stiffness, and potential weak zones to a depth of approximately 30 m. This study aims to identify and map the susceptible areas to abrasion in Seluma Regency coastal region and to analyze the causal factors associated with parameters elasticity of subsurface rocks. Data acquisition, processing, and inversion have been parameterized and selected to produce shear wave velocities representing actual subsurface conditions using Win-MASW 5.0 Professional software. The shear wave velocity analysis shows that the coastal area of Seluma Regency has the potential for high and moderate ground deformation which is vulnerable to abrasion. The area with high deformation potential is the Air Periukan Sub-Regency, Seluma Regency, Indonesia.