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Analisa Lapisan Sedimen Bawah Permukaan Pada Pembangunan Jalan Elevated Danau Dendam Tak Sudah Kota Bengkulu Menggunakan Metode HVInv Setyowati, Yuni; Farid, Muchammad; Ismul Hadi, Arif; Helinnes, Putri; Hardiansyah, Debi; Refrizon, Refrizon; Gumanty, Usman; Raihana, Hana; Rahmat Al-Ansory, Andre; Taufiqurrahman Syah, Muhammad
Jurnal Ilmu Fisika Vol 16 No 2 (2024): September 2024
Publisher : Jurusan Fisika FMIPA Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jif.16.2.187-197.2024

Bengkulu City is situated within a subduction zone where the Indo-Australian and Eurasian tectonic plates converge, rendering the area highly susceptible to seismic activity. This study employs the microseismic method to assess seismic vulnerability and the subsurface rock structure at the Dendam Tak Sudah Lake Flyover Construction Site in Bengkulu City, which encompasses a swampy region. The microseismic method used was an inversion of the horizontal to vertical (H/V) spectral ratio (HV-Inv) for determining the dominant frequency (f0), amplification factor (A0), seismic sensitivity index (Kg), and shear wave velocity (Vs). The findings reveal that f0 in the study area range from 2.16 to 7.53 Hz, A0 vary from 0.40 to 3.79, and Kg values span from 0.03 to 6.04. The sedimentary layers exhibit an average thickness of 5-10 meters, with some locations showing significantly thicker sedimentary deposits. Notably, the highest seismic susceptibility is recorded at point T8. The Vs values range from 185.19 to 539.49 m/s, which are inversely proportional to the Kg values and indicate soil classifications varying from soft to medium. The overall seismic risk in the study area is moderate. These results offer key insights into geophysical and geological conditions in Bengkulu City, crucial for earthquake mitigation.

DELINEATING RESISTIVITY VALUES OF POTENTIAL GEOTHERMAL AREAS ALONG THE BOGOR FAULT USING 2D MAGNETOTELLURIC INVERSION Hardiansa, Debi; Farid, M; Hadi, Arif Ismul; Al-Ansory, Andre Rahmat; Raihana, Hana; Rahmawati, Nurul 'Ilmi
Indonesian Physical Review Vol. 8 No. 2 (2025)
Publisher : Universitas Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/ipr.v8i2.431

Kepahiang Regency, located in an active fault zone, has great geothermal potential with an estimated capacity of up to 154 MW(e), making it a strategic renewable energy source to be developed. This research discusses the geothermal potential in the Kabawetan area, Kepahiang, Bengkulu. The main objective of this research is to evaluate the potential of geothermal resources around the Bogor segment by analyzing the subsurface structure using the Magnetotelluric inversion method and 2D resistivity modeling, in order to identify prospective geothermal reservoir zones. It can evaluate the potential of geothermal reservoirs in Kepahiang. The method used is the Magnetotelluric method, which utilizes the Earth's natural electromagnetic field to determine the distribution of resistivity in the subsurface. The results of 2D modeling with the MT method show potential zones associated with variations in subsurface thermal conditions and the presence of conductive clay minerals with resistivity values between 0.14-1 Î©m. These minerals are thought to be associated with the overburden (reservoir) of the geothermal system that has a depth of 2-4 km. The subsurface layer containing hot water and steam originating from heat emitted from the earth's core with a resistivity value of 2.5-45 Î©m at a depth of 1-4 km is thought to be caprock in the geothermal system, a resistivity value of 120-800 Î©m is thought to be hot rock with a depth between 1.5-10 km. It is estimated that there is a type of andesite rock that has been fractured as a reservoir of geothermal fluid. The findings of this research are expected to contribute to renewable energy as an alternative energy in the future, not only for energy needs but also for regional economic development through tourism and to support sustainable governance.

Estimation of Geothermal Potential Area in Kabawetan Sub-District, Using 2D Magnetotelluric Inversion Method Gumanty, Usman; Farid*, Muchammad; Refrizon, Refrizon; Azzahra, Gusti Ayu Zahwa; Nurhayati, Ratna Dewi; Al Ansory, Andre Rahmat; Raihana, Hana
Aceh International Journal of Science and Technology Vol 14, No 1 (2025): April 2025
Publisher : Graduate School of Universitas Syiah Kuala

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13170/aijst.14.1.44628

Kabawetan is located in the subduction zone of the magmatic arc in the Indonesian tectonic system. The geothermal energy potential in this region is closely tied to volcanic activity, which is prevalent along the Ring of Fire on the island of Sumatra. This study aims to identify the distribution of subsurface resistivity values related to geothermal potential in the Kabawetan Region. To achieve this, the magnetotelluric (MT) method is used, utilizing electrical and magnetic sensors. Data were collected using two horizontal electrical sensors (Ex, Ey) and three magnetic sensors, including two horizontal sensors (Hx, Hy) and one vertical sensor (Hz). Measurements using the magnetotelluric method can be used to determine the subsurface rock layers based on resistivity values. The results of data processing yield a 2D cross-section of the resistivity value, which characterizes the potential for geothermal energy. This study used four measurement points to analyze resistivity variations and determine geothermal potential. Field measurement data were processed using MAPROS software, and a 2D cross-section model was created using ZONDMT2D. The results showed that resistivity values of 20-60 m, thought to be impermeable overburden, were at depths of 0-1.5 km and 2.5-4 km, resistivity values of 0.54-1 m indicated permeable reservoirs at depths of 1.5-2.5 km, and resistivity values of 290-550 m indicated geothermal rocks at depths of 4-10 km. The findings of this research are expected to enhance the understanding of geothermal energy as a renewable resource, thereby supporting the Sustainable Development program.

HVSR Microtremor Analysis to Assess Subsurface Fault Characteristics and Geothermal Potential in Kepahiang Rabbani, Muhammad Rifqi; Hadi, Arif Ismul; Harlianto, Budi; Farid, Muchammad; Raihana, Hana; Anggi, Arya Putra
JURNAL GEOCELEBES Vol. 9 No. 2: October 2025
Publisher : Departemen Geofisika, FMIPA - Universitas Hasanuddin, Makassar

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.70561/geocelebes.v9i2.43347

Kepahiang, Bengkulu, is an area with considerable geothermal potential, especially in the Air Sempiang and Babakan Bogor areas. This study aims to analyze subsurface fault characteristics and assess geothermal potential using the Horizontal-to-Vertical Spectral Ratio (HVSR) microtremor method. This passive seismic method is used to determine key geophysical parameters, including dominant frequency (f0), amplification factor (A0), shear wave velocity (vs), and primary wave velocity (vp), which are essential for characterizing subsurface geological structures and identifying geothermal reservoir zones. The results show that dominant frequency values in Kepahiang range from 1.24 Hz to 20.45 Hz, while the amplification factor varies between 1.29 and 7.22. vs values range from 121.61 m/s to 3251.79 m/s, and vp values range from 214.91 m/s to 6469.79 m/s. These findings suggest that the surface layer consists mainly of alluvium and hard sandy gravel, with thicknesses varying between 10 and 50 meters. The 3D subsurface model constructed from the data indicates the presence of fault-controlled geothermal manifestations, mainly influenced by the Babakan Bogor Fault and Bogor Fault. These faults facilitate the upward migration of geothermal fluids, forming surface manifestations such as hot springs, fumaroles, and altered rocks. The geothermal system in the study area is classified as a low-temperature geothermal system, mainly caused by residual magmatic heat from Kaba Mountain and Bukit Hitam Crater. This research provides important insights for geothermal energy exploration and geotourism development in Kepahiang. These findings serve as a scientific basis for future geothermal resource assessment, land use planning, and sustainable energy utilization.

Analysis of Earthquake Risk Estimation for Sustainable Development Using Microtremor Data Based on Vs30 Distribution: Comparative Study of DFA and Geopsy in Central Bengkulu, Indonesia Arya Putra Anggi; Refrizon, Refrizon; Harlianto, Budi; Apriyanti, Nurul; Saputri, Winda; Febriansyah, Gian Ori; Al-Ansory, Andre Rahmat; Raihana, Hana; Daniel, Adrian; Gumanty, Usman
Jurnal Ilmu Fisika Vol 17 No 2 (2025): September 2025
Publisher : Jurusan Fisika FMIPA Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jif.17.2.214-228.2025

This research was conducted in Pondok Kelapa Subdistrict, Central Bengkulu Regency, to analyze subsurface characteristics using microtremor data and the Horizontal-to-Vertical Spectral Ratio (HVSR) method. The research compared DFA (Diffuse Field Assumption) and Geopsy approach. In this study, 40 points were measured with a distance between points ranging from 200 to 300 meters. The data were processed using Terraware-HV and Geopsy software with a Monte Carlo approach to model the 3D subsurface structure. Results show that the dominant frequencies range from 0.64 to 8.19 Hz, with high amplification zones between 1.92 and 7.72 concentrated in areas of loose soil, indicating their high seismic susceptibility. Vs30 values range from 55 to 465 m/s, reflecting the dominance of soft to medium materials, such as clay, gravel, sand, and soft rock at specific depths. 3D modeling revealed a heterogeneous distribution of subsurface materials, with high amplification zones requiring special mitigation. This study provides important insights for seismic risk zoning, disaster mitigation, and earthquake-resistant structure design, and supports sustainable development planning in earthquake-prone areas. The results are expected to serve as a reference in spatial management based on earthquake risk mitigation.

Utilization of Satellite Imagery and Integration of the HVSR Inversion Method for Coastline Changes in the Nangai Beach Tourism Area, North Bengkulu Regency Helinnes, Putri; Hadi, Arif Ismul; Farid, Muchammad; Setyowati, Yuni; Hardiansa, Debi; Gumanty, Usman; Raihana, Hana; Al-Ansory, Andre Rahmat; Muammar, Zaky
Buletin Oseanografi Marina Vol 14, No 3 (2025): Buletin Oseanografi Marina
Publisher : Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/buloma.v14i3.68258

This research analyzes shoreline changes in the Nangai Beach area; North Bengkulu Regency using Satellite Image data and analyzes subsurface structures using the Horizontal to Vertical Spectral Ratio (HVSR) method. The main objective of this research is to identify shoreline changes along the Nangai Beach area that occur due to abrasion. Data were collected from 30 points, with a distance of ±100 meters between each point. The research shows that the condition of the area is quite stable to vulnerable to the occurrence of abrasion disasters. Coastline changes were obtained using Satellite Image data from 2011 to 2023. Changes can be observed between points 17 and 35.63 meters, and at point 2, 33.87 meters. The Horizontal-to-Vertical Spectral Ratio (HVSR) method determines dominant frequency values and processes them through amplification to calculate the seismic vulnerability index, sediment layer thickness, and shear wave speed. These values are used to identify areas vulnerable to coastal abrasion. Based on the interpretation, hard rock is shown with a dominant frequency value () in the range 2.35-5.08 Hz, while soft rock is shown in the range 5.71-9.05 Hz. The earthquake vulnerability value () in the range 0.49-2.68 is soft rock, while the value range 3.42-5.61 is hard rock. The lower the vulnerability value (), the more susceptible the area is to abrasion. The shear wave velocity () value is low with a range of 186.83-350.85 while the high value is with a range of 350.85-596.87. A layer of rock with a 3D cross-section can be viewed using 3D modeling software by entering the value of Vs. This research makes a significant contribution to abrasion disaster mitigation through a geophysical approach.

Analisa Lapisan Sedimen Bawah Permukaan Pada Pembangunan Jalan Elevated Danau Dendam Tak Sudah Kota Bengkulu Menggunakan Metode HVInv Setyowati, Yuni; Farid, Muchammad; Ismul Hadi, Arif; Helinnes, Putri; Refrizon, Refrizon; Hardiansyah, Debi; Gumanty, Usman; Raihana, Hana; Rahmat Al-Ansory, Andre; Taufiqurrahman Syah, Muhammad
Jurnal Ilmu Fisika Vol 16 No 2 (2024): September 2024
Publisher : Jurusan Fisika FMIPA Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jif.16.2.187-197.2024

Bengkulu City is situated within a subduction zone where the Indo-Australian and Eurasian tectonic plates converge, rendering the area highly susceptible to seismic activity. This study employs the microseismic method to assess seismic vulnerability and the subsurface rock structure at the Dendam Tak Sudah Lake Flyover Construction Site in Bengkulu City, which encompasses a swampy region. The microseismic method used was an inversion of the horizontal to vertical (H/V) spectral ratio (HV-Inv) for determining the dominant frequency (f0), amplification factor (A0), seismic sensitivity index (Kg), and shear wave velocity (Vs). The findings reveal that f0 in the study area range from 2.16 to 7.53 Hz, A0 vary from 0.40 to 3.79, and Kg values span from 0.03 to 6.04. The sedimentary layers exhibit an average thickness of 5-10 meters, with some locations showing significantly thicker sedimentary deposits. Notably, the highest seismic susceptibility is recorded at point T8. The Vs values range from 185.19 to 539.49 m/s, which are inversely proportional to the Kg values and indicate soil classifications varying from soft to medium. The overall seismic risk in the study area is moderate. These results offer key insights into geophysical and geological conditions in Bengkulu City, crucial for earthquake mitigation.

INVESTIGATION OF THE GEOTHERMAL RESOURCE POTENTIAL USING GEOELECTRICAL METHOD WITH THE WENNER CONFIGURATION: A CASE STUDY IN LEBONG REGENCY, INDONESIA Raihana, Hana; Nazli, Khairun; Suhendra, Suhendra; Refrizon, Refrizon; Halauddin, Halauddin
Indonesian Physical Review Vol. 6 No. 2 (2023)
Publisher : Universitas Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/ipr.v6i2.225

In geothermal reservoirs, hydrothermal distribution is significant. The most widely utilized geothermal reservoirs to date are those of hydrothermal systems, which are geothermal systems where the reservoir contains steam, water, or a mixture of both, depending on the pressure and temperature of the reservoir. One of geophysical method that is enough to map subsurface conditions to determine the hydrothermal distribution is the 2-Dimensional Geoelectric method using the Wenner configuration. This method aims to study the variation of rock resistivity below the earth's surface, resulting in a two-dimensional profile of the subsurface resistivity model used to describe the layered subsurface resistivity structure. The results are in the form of 2-Dimensional modeling of the distribution of hydrothermal manifestations with data processing using pyGIMLI (Python Library for Inversion and Modeling in Geophysics) software. In the study area Â Pungguk Pedaro Village, Bingin Kuning District, Lebong Regency, the Hulusimpang Formation has a high alteration intensity, as evidenced by the weathering in rocks and the micrographic appearance. The types of stones found in this research area include andesite rocks, including sandy gravel, volcanic breccia, tuff, andesite, basalt, basalt-andesite sand, silty sand, and clay. Or rocks derived from acidic magma.

IDENTIFICATION OF HYDROTHERMAL DISTRIBUTIONS USING THE WENNER-SCHLUMBERGER CONFIGURATION GEOELECTRIC METHOD IN LEMEU VILLAGE, LEBONG REGENCY, BENGKULU Kausari, Alfata; Rafly, Tegar Al; Muammar, Zaky; Refrizon, Refrizon; Halauddin, Halauddin; Suhendra, Suhendra; Sahputra, Rio; Raihana, Hana; Rahmat, Andre
Indonesian Physical Review Vol. 7 No. 3 (2024)
Publisher : Universitas Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/ipr.v7i3.332

The hot spring pool, Lemeu Village, Lebong Regency, is one of the geothermal fields. This research aims to identify the study area's geothermal potential and lithology. This is illustrated by the correlation method of resistivity and electrical conductivity values of rocks based on geoelectric measurements. This research uses the Wenner-Schlumberger configuration geoelectric method, as many as four tracks spread around the hot spring hill with a length of 480 meters, which are used to see variations in resistivity values that can indicate the presence of hydrothermal potential. The result is a 2D Resistivity model processed with Res2DinvX32 software. Based on the interpretation results, the subsurface rock lithology in each track is relatively similar in color, texture, grain size, and composition because it is around the hill. The Hulusimpang formation consists of clay, silty sand, tuff, andesite, basalt, and granite. Hydrothermal is found on lines 2 and 4 with resistivity values of 7.3 and 10.1 Î©m at a depth of 26 meters. Geothermal potential in the research area is divided into several temperature categories; some have low, medium, and high temperatures. In the research area, tracks 1 and 3 have low temperatures.

IDENTIFICATION OF AQUIFERS BASED ON THE VERTICAL ELECTRICAL SOUNDING (VES) METHOD SCHLUMBERGER CONFIGURATION CASE STUDY: PULAU BAAI KAMPUNG MELAYU SUB-DISTRICT, BENGKULU CITY, INDONESIA Rafly, Tegar Al; Refrizon, Refrizon; Hadi, Arif Ismul; Ansory, Andre Rahmat Al; Raihana, Hana
Indonesian Physical Review Vol. 8 No. 1 (2025)
Publisher : Universitas Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/ipr.v8i1.333

Investigation of the groundwater potential in the Pulau Baai area, Kampung Melayu Sub-district, Bengkulu City, must be carried out in such a way that the activities and needs of the people in the area can be fulfilled and the needs of the population in the area can be met. This study aims to determine the status of groundwater using the Schlumberger configuration geoelectric method. Measurements were made using a resistivity meter, and the results for each configuration depended on changes in resistivity. Measurements for each configuration depend on changes in resistivity at depth, the vertical direction (sounding), and the lateral direction (mapping), so hydrogeological analysis in this activity aims to get the maximum use of groundwater / underground water in aquifers for raw water needs. The dominant rock structures in the study area are clay, alluvium, siltstone, and sandstone, as well as some rocks with suitable porosity and permeability as water carriers, such as sand and gravel. However, what appears to have considerable potential is that groundwater is found at depths of 4-53 meters in VES 1, VES 2, VES 3, VES 5, and VES 10. The results of the analysis show that the location of the Pulau Baai, Kampung Melayu Sub-district, Bengkulu City Priority Utilization Area is within the groundwater storage area, so it can be used to meet the raw water needs of the study area.

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