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Indonesian Journal on Geoscience

IJOG
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Published by Institut Teknologi Nasional Yogyakarta

ISSN : 23559314 EISSN : 23559306 DOI : http://ijog.bgl.esdm.go.id/index.php/IJOG/article/

Core Subject : Science, Engineering,

Earth & Planetary Sciences Engineering

The spirit to improve the journal to be more credible is increasing, and in 2012 it invited earth scientists in East and Southeast Asia as well as some western countries to join the journal for the editor positions in the Indonesia Journal of Geology. This is also to realize our present goal to internationalize the journal, The Indonesian Journal on Geoscience, which is open for papers of geology, geophysics, geochemistry, geodetics, geography, and soil science. This new born journal is expected to be published three times a year. As an international publication, of course it must all be written in an international language, in this case English. This adds difficulties to the effort to obtain good papers in English to publish although the credit points that an author will get are much higher. This Journal publishes 3 numbers per year at least 15 articles. It is a challenge for the management of the journal to remain survive and at the same time continuously maintain its quality and credibility in spite of those various constraints. Fortunately, this effort is strongly supported by the Geological Agency of Indonesia, as the publisher and which financially bear the journal. Last but not least the journal is also managed by senior geologist of various subdisciplines from various countries who are responsible for its quality.

Arjuna Subject : Ilmu Bumi dan Planet (semua kategori) - Geologi

Articles 324 Documents

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Determination of Deep Well Using Resistivity Method in South Amanuban, Timor Tengah Selatan Regency, Indonesia Supandi, Supandi
Indonesian Journal on Geoscience Vol 8, No 2 (2021)
Publisher : Geological Agency

DOI:10.17014/ijog.8.2.255-264South Amanuban often experiences drought during dry seasons, because the area is composed of Quaternary deposits with plain topography. Therefore, this research aims to identify and to evaluate the Quaternary deposit of groundwater potential, and to determine the deep well points in South Amanuban. The study utilized the geo-electrical method with the resistivity value approach to find high resistivity soils as aquifer layers. In addition, the deep well points are determined based on consideration of the aquifer positions from the resistivity analysis. The results show that aquifer positions are found in the limited zone of 50-150 m depth with lense shapes that are not related to each other.

Investigation of Dam Integrity from Electrical Resistivity Methods: A Case of Erelu Dam, Southwestern Nigeria Olasunkanmi, Nurudeen Kolawole; Sunmonu, L.A.; Owolabi, D.T.; Bawallah, M.; Oyelami, Azizat
Indonesian Journal on Geoscience Vol 8, No 2 (2021)
Publisher : Geological Agency

DOI:10.17014/ijog.8.2.265-274Erelu dam is geologically within the Precambrian Basement Complex of southwestern Nigeria, which serves a principal source of water supply to an increasing population; currently at about 779,318. In an attempt to investigate the integrity of the dam, horizontal resistivity profiling (HRP) of dipole-dipole and Schlumbergerâ€™s vertical electrical sounding (VES) approaches were explored to delineate the lithologic layers, facies, and geologic structures in the subsurface of the dam. The HRP revealed changes in subsurface conductivity that depicts lateritic hard pan and saturated rock blankets at shallow depth. The vertical geo-electric section delineated predominant four lithologic units. The regolith is 7 m thick and constitutes the vertical rock fill impervious cores of the dam, which is underlained by saprolitic and fresh bedrock. The region of weathered rock depression coincided the shallow saturated anomalous zone and showed surface manifestation of fractured or unconsolidated terrain within the embankment. The fracture serves as conduit for seepage which could be responsible for possible loss in the reservoir water and increases its susceptibility to failure. It is recommended to keep monitoring the seepage with reservoir levels, by periodical geophysical and geotechnical measurements for the two (dry and wet) seasons.

Spatial Variability in Macro- and Microtextures of A Tropical Intermontane Peatland: Preliminary Investigation into The Kutai Lake Peat System, East Kalimantan, Indonesia Anggara, Ferian; Muchitawati, Guritno Safitri; Moore, Tim. A.; Septantia, Afrina
Indonesian Journal on Geoscience Vol 8, No 2 (2021)
Publisher : Geological Agency

DOI:10.17014/ijog.8.2.275-296Peat deposits of the Muara Siran, East Kalimantan area, were investigated for their vertical and lateral succession, to examine the characteristic variability, particularly its macro- and microtextures. The deposits are situated in the Kutai Basin, in the vicinity of several Cenozoic coal deposits. Peat samples were taken from twenty-seven coring sites in the area, using a MacCaulay peat corer. The Muara Siran peatlands lie between the Kedang Kepala and Belayan Rivers. Siran Lake lies between these rivers and within the peat system. The peat thickness varied from 0.5 m to 12 m. Decomposed sapric peat formed the basal and margins of the deposit, overlain by moderately decomposed hemic peat in the central part of the peatlands, though both sapric and hemic peat types are interbedded at the margins of the mire. The fibric peat types were found mostly at the top of the mire and only distal from any active streams. Twenty-four samples of peat were freeze-dried for petrographic analyses of both plant part and maceral analyses using a reflected microscope. On the average, the dominant plant parts were stems and wood (i.e. secondary xylem). Maceral composition was mostly from the huminite group (on the average 89%), particularly the macerals humodetrinite and textinite. Macroscopic peat type and microscopic composition are linked. Fibric peat was found to be rich in wood and textinite. Hemic was mostly composed of stems and wood with textinite and humodetrinite as the most abundant macerals. Sapric peat has near equal proportions of stems, wood, and macerated tissue. Humodetrinite is the most abundant maceral in sapric. The average ash and sulfur content were low, 1.29 wt.% and 0.11 wt.%, respectively. Understanding the physical characteristics of inland peat as in Muara Siran peatland is essential to build knowledge of how inland peat is formed and what makes it different from coastal peat. Muara Siran is a unique, relatively small peatland in the central eastern Kalimantan which is still considerably pristine, hence may serve the aim of this study well. Â

Estimation of Heat Flow Using a Bottom Simulating Reflection Based on 3D Seismic Data, West Africa Le, Anh Ngoc
Indonesian Journal on Geoscience Vol 8, No 3 (2021)
Publisher : Geological Agency

A Bottom Simulating Reflection (BSR) has been identified using 3D seismic data from the Cameroon continental slope margin. The BSR covers an area of c. 350 km2 in water depths ranging between 940 m to 1,750 m across an area characterized by high- and low-gradient slopes, gullies, scours, and fans. The thickness of the Gas Hydrate Stability Zone (GHSZ) is ~100 - 250 m, assuming an average velocity of 1,800 m/s. Pockmarks are intensively developed across the slope and most of them are observed in the BSR area. Geothermal estimation is based on hydrate stability conditions for pure methane - seawater system, hydrostatic pressure model, and a range of P-wave velocity models for the GHSZ, ranging from 1,600 -1,800 to 2,000 - 2,200 m/s. Geothermal gradient is calculated showing the range and distribution of thermal gradients in the BSR area from 0.046 C/m to 0.094 oC/m with assumed GHSZ velocity of 1,800 m/s. Thermal gradient anomalies have been observed in association with gullies, vertically stacked channels and in some individual pockmarks. The highest anomalies of 0.08 C/m â€“ 0.094 C/m are found in the depression areas of pockmark trains, within seafloor gullies. These positive anomalies are most likely controlled by active or recently active fluid advection and expulsion through the Cameroon slope.

Landslide Potential Investigation for Disaster Risk Reduction in Central Bengkulu Regency, Bengkulu Province, Indonesia Hadi, Arif Ismul; Refrizon, Refrizon; Farid, Muchammad; Harlianto, Budi; Sari, Julia Inti
Indonesian Journal on Geoscience Vol 8, No 3 (2021)
Publisher : Geological Agency

Bengkulu Province is the converging path region between the Indo-Australian - Eurasian tectonic plates in the ocean and the Sumatran f ault crossing on the mainland. The condition implies that the sliding force of the slab is easy to trigger fractures and to cause the material to be relatively less elastic, resulting in high seismic intensity. This study aims to identify areas with the potential for landslides and its mapping, and to analyze the factors that cause landslides in Central Bengkulu Regency, Bengkulu Province, Indonesia. This study was conducted using rock physical parameters of ground shear strain (GSS) which were correlated with parameters of slope, slope height, Vs30 value, fault distance to measurement point, rock conditions, rainfall, and PGA value. Furthermore, these parameters were overlaid thoroughly by the statistical method of the Analytical Hierarchy Process (AHP). Data acquisition is divided into two stages, namely the secondary data collection stage and the field survey stage. Secondary data collection was carried out to support the creation of landslide potential maps, analysis, and field survey data input. Secondary data is the value of Vs 30, the distance of the fault to the measurement point, rainfall, and the PGA value. Field survey data are in the form of GSS values, slope, slope height, and rock conditions. The results of this study are identified areas that have the category of high, medium, and low landslide potential. Based on the calculated parameters, the GSS parameter is the most dominant which affects the landslide potential in the studied area.

A Simple But Effective Approach of Building Footprint Extraction in Topographic Mapping Acceleration Susetyo, Danang Budi; Rizaldy, Aldino; Hariyono, Mochamad Irwan; Purwono, Nugroho; Hidayat, Fahrul; Windiastuti, Rizka; Rachma, Tia Rizka N.; Hartanto, Prayudha
Indonesian Journal on Geoscience Vol 8, No 3 (2021)
Publisher : Geological Agency

Topographic mapping using stereo plotting is not effective, because it takes much time and labour-intensive. Thus, this research was conducted to find the effective way to extract building footprint for mapping acceleration from LiDAR data. Building extraction method in this process comprises four steps: ground/non-ground filtering, building classification, segmentation, and building extraction. Classification of ground and non-ground classes was performed using Adaptive-TIN Surface algorithm. Non-ground points from filtering process were classified as building with the algorithm based on multiscale local dimensionality to separate points at the maximum separability plane. Segmentation using segment growing was used to separate each building, so boundary detection could be conducted for each segment to create boundary of each building. Lastly, building extraction was conducted through three steps: boundary point detection, building delineation, and building regularization. With ten samples and step 0.5, classification resulted in quality and miss factor of 0.597 and 0.524, respectively. The quality was improved by segmentation process to 0.604, while miss factor was getting worse to 0.561. Meanwhile, on the average shape index value from extracted building had 0.02 difference, and the number of errors was 30% for the line segment comparison. Regarding positional accuracy using centroid accuracy assessment, this method could produce RMSE of 1.169 m.

Interpretation of Magnetic Anomaly Data in the Andesitic Rock Prospect Area of Kutasari Subregency, Purbalingga Regency, Central Java, Indonesia Sehah, Sehah; Raharjo, Sukmaji Anom; Prabowo, Urip Nurwijayanto; Sutanto, Dwi Setiawan
Indonesian Journal on Geoscience Vol 8, No 3 (2021)
Publisher : Geological Agency

Interpretation of magnetic anomaly data has been carried out in the andesitic rock prospect area, Kutasari Subregency, Purbalingga Regency, Central Java, Indonesia. Geographically, this area is located within 109.2788Â° - 109.3072Â°E and 7.3032Â° - 7.3319Â°S. The study has been done in April â€“ September 2019 with the purpose to map the distribution of andesitic rocks based on the local magnetic anomaly data. The data that are acquired in this study have the values ranging between -1,238.13 - 1,892.40 nT. The results of qualitative interpretation on the local magnetic anomaly data having been reduced to the pole show the distribution of strong anomalous sources in the northwest area interpreted as massive andesitic rocks. Whereas the results of quantitative interpretation through 2D-forward modeling on the local magnetic anomaly data show six anomalous bodies, with magnetic susceptibility values ranging from 0.0025 to 0.0350 cgs and depths range between 7.16 - 505.97 m. The highest magnetic susceptibility is 0.0350 cgs interpreted as a massive andesite intrusion forming a very dense dike; whereas the lowest magnetic susceptibility is 0.0025 cgs interpreted as undifferentiated igneous rocks, volcanic breccias, lava, and tuff. Based on the study results, the correlation between the results of qualitative and quantitative interpretations occurs.

Vertical Electrical Sounding Exploration of Groundwater in Kertajati, Majalengka, West Java, Indonesia Nugraha, Gumilar Utamas; CSSSA, Boy Yoseph; Nur, Andi Agus; Pranantya, Pulung Arya; Handayani, Lina; Lubis, Rachmat Fajar; Bakti, Hendra
Indonesian Journal on Geoscience Vol 8, No 3 (2021)
Publisher : Geological Agency

Continuously increasing population and progressive infrastructural development in the region of Kertajati International Airport, Indonesia, emphasize the need to develop a sustainable water supply network. Airport facilities require sufficient water resources, which can be obtained from surface water and groundwater. Groundwater exploration can provide necessary information for assessing water resources. The purpose of this study is to analyze the configuration of aquifers in the studied area. A Schlumberger array was used to carry out twelve vertical electrical soundings (VES) with AB/2 electrode spacing ranging from 1.5 m to 150 m. IPI2win software was used to qualitatively interpret the VES results and it suggested the presence of three distinct lithological units interpreted as clay, alluvial sand, and a Lower Quaternary formation. In general, resistivity values in the studied area can be divided into five resistivity categories: very low resistivity with values ranging from 1 Î©m to 10 Î©m, low resistivity with values ranging from 10 Î©m to 50 Î©m, medium resistivity with values ranging from 50 Î©m to 100 Î©m, high resistivity with values ranging from 100 Î©m to 200 Î©m, and very high resistivity with values > 200 Î©m. The geo-electric interpretation revealed three geo-electric layers: topsoil (1 - 144 â„¦ m), sand (1 - 298 â„¦ m), and clay (1 - 82 â„¦ m). Aquifers in the studied area are lithologically composed of sand. Clay is the dominant lithology in the studied area, so the presence of aquifers in this area is very limited, and thus the supply of groundwater is also limited. The exploitation of groundwater must be limited and controlled to maintain the sustainability of groundwater in the studied area.

Implementation of Seismic Ground Response Analysis in Estimating Liquefaction Potential in Northern Thailand Mase, Lindung Zalbuin; Likitlersuang, Suched
Indonesian Journal on Geoscience Vol 8, No 3 (2021)
Publisher : Geological Agency

It has been known that northern Thailand is an active tectonic region in Southeast Asia. Some earthquakes with low to medium magnitudes had occurred in northern Thailand. The Mw6.1 Mae Lao Earthquake occurred on May 5th, 2014 in Chiang Rai Province. The earthquake also resulted in the unique phenomenon of ground failure, which was known as liquefaction. Learning from the event, the liquefaction potential based on seismic ground response analysis was performed. Several site investigations including standard penetration test and seismic down-hole test in Chiang Rai Province were carried out. The next generation attenuation model was conducted to generate the ground motion for nonlinear seismic response analysis. The peak ground acceleration at the ground surface from seismic ground response analysis was used to analyze the empirical analysis of liquefaction potential. The results show that liquefaction could occur at the investigated locations during the earthquake. The results also confirm the liquefaction evidence found in Chiang Rai Province during the Mw 6.1 Mae Lao Earthquake. This research can help the people to consider the earthquake impacts to northern Thailand.

The Application of Parametric and Nonparametric Regression to Predict The Missing Well Log Data Mordekhai, Mordekhai; Qudsi, Izzul; Guntoro, John Papilon Steven
Indonesian Journal on Geoscience Vol 8, No 3 (2021)
Publisher : Geological Agency

Incomplete well log data are very commonly encountered problems in petroleum exploration activity. The development of artificial intelligence technology offers a new possible way to predict the required logs using limited information available. Optimizing conventional statistical theory, machine learning is proven to be a reliable tool for any prediction task in many fields of study. Regression is one of the basic methods that has rapid development and evolved many techniques with different approaches and purposes. In this study, parametric and nonparametric regressions {linear regression, Support Vector Machine (SVM), and Gaussian Process Regression (GPR)} are compared to predict the missing log using the available nearby data. Feature selection was done by performing Principal Component Analysis (PCA) on predictor variables. Different profile of PCA is observed between Cibulakan and Parigi Formations, which is the basis of conducting separate models based on the formation. Among all the selected methods, GPR is consistently making slightly better results. The correlation between the predicted and actual porosity of GPR is observed to be up to 0.19 higher compared to the other methods. Similar observation is also found on the Root Mean Squared Error (RMSE) value comparison. In practice, the GPR method has an inherent advantage compared to other methods, as it provides uncertainty to the prediction based on the standard deviation of each estimation result. The standard deviation of the GPR prediction ranges from 0.006 in high confidence cases and up to 0.077 where uncertainty is high. The models are considered robust and stable according to the RMSE evaluation from cross validation which is consistently giving the value below 0.04. In conclusion, the reliability of regression techniques for predicting the missing well log is exposed in this study, which results demonstrate steady and good accuracy in every formation which are tested on any well logs.

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bernadeta subandini astuti

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Home Page

OAI Link

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Contact Name bernadeta subandini astuti

Contact Email bernadeta.palguno@gmail.com

Phone +6222-7213793

Journal Mail Official ijog@bgl.esdm.go.id

Editorial Address Jl. Diponegoro No. 57 Bandung, Indonesia

Location Kab. sleman, Daerah istimewa yogyakarta INDONESIA

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Contact Name
bernadeta subandini astuti

Contact Email
bernadeta.palguno@gmail.com

Phone
+6222-7213793

Journal Mail Official
ijog@bgl.esdm.go.id

Editorial Address
Jl. Diponegoro No. 57 Bandung, Indonesia

Location
Kab. sleman,

Daerah istimewa yogyakarta

INDONESIA