Garuda - Garba Rujukan Digital

Empirical Equation between Predominant Frequency and Sediment Thickness in Plampang, West Nusa Tenggara Iswanto, Eko Rudi; Riyanto, Theo Alvin; Suntoko, Hadi
EKSPLORIUM Vol 44, No 2 (2023): November 2023
Publisher : Badan Riset dan Inovasi Nasional

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/eksplorium.2023.6918

Soil characteristics mapping is one of the essential aspects in the development of a region. Soil characteristics such as the predominant frequency and thickness of the sediment layer are needed to ensure the capacity of soil against the load of an infrastructure construction. The existence of tectonic activity causes West Nusa Tenggara Province to be an area with high seismic activity. Along with the plan to accelerate the development of the Samota Area, seismic studies are one of the aspects that determine project feasibility. The predominant frequency value from the results of microtremor measurements is used in the development of an empirical formula to predict soil thickness in the Plampang area. The empirical formula from previous research is used as a conformity test of the empirical formula obtained. Empirical equations are then used to map variations in sediment thickness in the Plampang area, which are justified based on geological data. The results of the sediment thickness map based on the empirical formula for the Plampang area showed a good correlation with the predominant frequency and also showed a good correlation with the results of the formula that has been carried out by previous studies.

Spatial analysis of sedimentation hazard in the catchment area of the Indonesia nuclear power plant Alhakim, Euis Etty; Setiawan, Muhammad Anggri; Mellawati, June; Iswanto, Eko Rudi; Setiaji, Abimanyu Bondan Wicaksono
Journal of Degraded and Mining Lands Management Vol. 12 No. 2 (2025)
Publisher : Brawijaya University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15243/jdmlm.2025.122.6953

Erosion and sedimentation resulting from land use changes can negatively impact watershed quality and threaten sustainability. Watershed quality is particularly crucial in areas designated for energy sector development, such as Nuclear Power Plants (NPPs). One potential NPP site in Indonesia is located downstream of the Raya watershed, where high river sedimentation may affect its performance. This study aimed to determine the spatial pattern of mean annual sediment yield in the Raya watershed using hydrological models. Due to the limited availability of data, secondary data analysis was employed, utilizing a geospatial hydrological modeling approach with the Soil and Water Assessment Tool (SWAT). The Hydrological Response Unit (HRU) was used as an analytical unit to identify physio-geographic similarities based on land use, soil type, and slope, which serve as dynamic hydrological controls. The results reveal the hydrological characteristics of the Raya watershed: an elongated shape, a dendritic river network, and moderate drainage density. The average slope is 12.6%, with a clay-loam soil texture and land cover dominated by dryland forests, oil palm plantations, and mining activities. The SWAT model produced an average sediment yield of 251.7 t/ha/year over a 10-year simulation period, classified as high sedimentation. High to very high sedimentation was predominantly found in the upstream areas, moderate sedimentation at the foothills, and low sedimentation in the alluvial plains downstream. These findings indicate a decline in land quality in the Raya watershed, highlighting the need for conservation measures to ensure the sustainability of the watershed ecosystem.

Studi Mikrotremor dengan Metode Horizontal to Vertical Spectral Ratio (HVSR) di Tapak RDE, Serpong Iswanto, Eko Rudi; Indrawati, Yuni; Riyanto, Theo Alvin
EKSPLORIUM Vol. 40 No. 2 (2019): NOVEMBER 2019
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/eksplorium.2019.40.2.5489

Natural disaster like earthquake can cause damage to the site and the infrastructure including nuclear reactor facilities. This phenomenon needs comprehensively understood through its dynamic characteristics historical records of the site. The use of Horizontal to Vertical Spectral Ratio (HVSR) method has been widely used for subsurface investigation since last decade. The aimed of the research is to obtain local geological and subsurface dynamic characetristics. This research is applying the use of HVSR method for Experimental Power Reactor (RDE) in Serpong. The measurements are in 15 locations, and then the data is processed by using Geopsy software. The analysis result shows that the RDE site has dominant frequncy values between 3.06 Hz–23.271 Hz and amplification factor 1.84–6.37. The northeast and southeast areas of the site have higher seismic vulnerability index than in other area. Therefore, the selection for reactor bulding location in the southwest area is proper because it has lower amplification factor, sedimen thickness, and seismic vulnerability index.

Mikrozonasi di Daerah Plampang, Nusa Tenggara Barat Iswanto, Eko Rudi; Riyanto, Theo Alvin; Suntoko, Hadi
EKSPLORIUM Vol. 42 No. 1 (2021): MEI 2021
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/eksplorium.2021.42.1.6243

Nusa Tenggara Barat (NTB) Province is an area with intense seismic activity. This phenomenon is caused by tectonic activity as the result of the convergency of the Eurasia-Australia Plates (subduction zone) in the south and the Flores Fault in the north as well as the presence of local faults. Regarding the plan to develop the Samota area in Sumbawa Island, NTB, a study concerning earthquakes should be done. The purpose of this study is to map the seismic vulnerability index (Kg) through microtremor measurement by using the Horizontal to Vertical Spectral Ratio (HVSR) analysis method. The result of the study is a seismic vulnerability map of the Plampang area which its northern part has a low seismic vulnerability index indicated by the amplification factor value of less than three compared to other areas. The geology of the northern part of the Plampang area consists of volcanic rocks which has hard rock characteristic, very thin sediment thickness, and composed of Tertiary or older rocks. Seismic vulnerability maps can be useful as a reference for earthquake mitigation to reduce its risks.

Empirical Equation between Predominant Frequency and Sediment Thickness in Plampang, West Nusa Tenggara Iswanto, Eko Rudi; Riyanto, Theo Alvin; Suntoko, Hadi
EKSPLORIUM Vol. 44 No. 2 (2023): NOVEMBER 2023
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/eksplorium.2023.6918

Soil characteristics mapping is one of the essential aspects in the development of a region. Soil characteristics such as the predominant frequency and thickness of the sediment layer are needed to ensure the capacity of soil against the load of an infrastructure construction. The existence of tectonic activity causes West Nusa Tenggara Province to be an area with high seismic activity. Along with the plan to accelerate the development of the Samota Area, seismic studies are one of the aspects that determine project feasibility. The predominant frequency value from the results of microtremor measurements is used in the development of an empirical formula to predict soil thickness in the Plampang area. The empirical formula from previous research is used as a conformity test of the empirical formula obtained. Empirical equations are then used to map variations in sediment thickness in the Plampang area, which are justified based on geological data. The results of the sediment thickness map based on the empirical formula for the Plampang area showed a good correlation with the predominant frequency and also showed a good correlation with the results of the formula that has been carried out by previous studies

Assessing Watershed Characteristics and Hydrological Response Using SWAT: A Case Study in the Raya Watershed, West Kalimantan Alhakim, Euis Etty; Bondan, Abimanyu; Iswanto, Eko Rudi; Anzhar, Kurnia; Indrawati, Yuni; Solihat, Sufiana; Setiawan, Muhammad Anggri
EKSPLORIUM Vol. 46 No. 1 (2025): MAY 2025
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/eksplorium.2025.11420

The watershed is primarily influenced by land use and population activities within the watershed area. Along with the increasing number of people, there is the potential for land-use changes that lead to a change in the land's function. This condition can cause soil erosion in the upstream areas and potential flooding in the downstream area of the watershed. This study aims to determine the hydrology response based on watershed characteristics in terms of annual flow coefficient (AFC) and geomorphology. Geospatial hydrological modeling was built to assess hydrological characteristics using the SWAT (Soil and Water Assessment Tool). The analysis utilized primary data from field surveys and secondary spatial data, including geological maps, DEM, land use, soil, and daily rainfall, from 2013 to 2022. The study area covers the Raya Watershed in West Kalimantan. It was found in the Raya Watershed that open land use is prominent, with slopes ranging from sloping to steep in the upstream areas. The type of soil generally had porosity that did not support water absorption. These conditions caused more rainfall to be discharged as surface flow than absorbed into the soil. The AFC value during the study period ranged from 0.36 to 0.45, indicating a moderate hydrological response. Thus, groundwater storage in the watershed was very low. Consequently, the hydrological response of the watershed is unable to function optimally in its current condition. To overcome these problems, land conservation strategies, reforestation, and rehabilitation of old mine fields in upstream sub-basins are needed to reduce runoff and improve the watershed's ability to maintain a sustainable water balance.

Title

Found 6 Documents
Search

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Title Search

Found 6 Documents Search

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Title

Found 6 Documents
Search