cover
Contact Name
Sri Mulyaningsih
Contact Email
sri_m@akprind.ac.id
Phone
+6222-7213793
Journal Mail Official
ijog@bgl.esdm.go.id
Editorial Address
Jl. Diponegoro No. 57 Bandung
Location
Unknown,
Unknown
INDONESIA
Indonesian Journal on Geoscience
ISSN : 23559314     EISSN : 23559306     DOI : https://doi.org/10.17014/ijog.3.2.77-94
Core Subject : Science,
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.
Articles 3 Documents
Search results for , issue "Vol 8, No 1 (2021): in-press" : 3 Documents clear
Earthquake Potential Hazard Analysis of Palembang City, Sumatra Island Triyoso, Wahyu; Suwondo, Aris; Naibaho, Zael Yahd Xanggam
Indonesian Journal on Geoscience Vol 8, No 1 (2021): in-press
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17014/ijog.8.1.1-9

Abstract

Most of the destructive earthquakes in Sumatra are dominated by thrust mechanisms that occur due to the process of subduction and some earthquakes with strike-slip fault sources such as the Sumatra fault and northwestern Sumatra. The subduction zones along western Sumatra and Sumatran fault zones are active seismic sources of earthquake events. The seismotectonics of South Sumatra can be affected by earthquakes triggered by these seismic sources. In this study, an estimation and analysis of the potential for earthquake hazard curves were carried out in Palembang City due to the influence of subduction zone sources, strike-slip faults, and intermediate to deep earthquake sources. The algorithm of the seismicity smoothing was applied to estimate the seismicity rate for megathrust sources, active faults, and intermediate to deep earthquake sources. The results of the earthquake hazard potential curve showed that the estimated Peak Ground Acceleration (PGA) in the bedrock of the subduction earthquake sources was greater than the estimated ground shaking due to strike-slip fault sources as well as intermediate to deep earthquake sources. To understand better the potential ground shaking, the evaluation of PGA at the surface was then estimated by including the amplification factor. The amplification factor was calculated using the Horizontal-Vertical Spectral Ratio (HVSR) method. Based on the PGA estimated at the surface of 10% probability exceedance level during 50 years, the Palembang City has a potential shaking of around 35 gal, which is likely to be caused by a megathrust earthquake source.
A Combined Petrographic-Geochemical Provenance and Tectonic Setting Study of Palaeozoic Rocks, in East Johor Basin, Peninsular Malaysia Surjono, Sugeng Sapto; Leman, Mohd. Shafeea; Mohamed, Kamal Roslan; Ali, Che Aziz
Indonesian Journal on Geoscience Vol 8, No 1 (2021): in-press
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17014/ijog.8.1.11-24

Abstract

Several greywacke sandstones considered as Paleozoic rocks are found in three different formations, i.e. the Dohol, Linggiu, and Tanjung Leman Formations within the Palaeozoic East Johor Basin. The compositions of twenty-nine sandstone samples were identified using petrographical and geochemical methods to determine the provenance of sandstones as well as the tectonic setting of pre-and syn-sedimentation. Seven samples of them were examined using point counting method to obtain the mineralogical compositions. This petrographical point counting was done by plotting composition percentages to QFL and QmFLt triangular diagrams, The results showed a magmatic arc for Dohol Formation, a change from a magmatic to a recycled orogen for Linggiu Formation, and a recycled orogen for Tanjung Leman Formation. The recycled orogen tectonic setting of Linggiu and Tanjung Leman may have come from the underlying metamorphic and sedimentary rocks of Mersing and Murau Formations. Meanwhile, twenty-two samples were examined using a geochemical method by utilizing the ratio of K2O/Na2O and SiO2. The samples suggest a tectonic setting from both passive continental margin (PM) and active continental margin (ACM). Based on these findings, it is interpreted that the sedimentary rocks in East Johor were deposited in a subduction-related basin, such as fore-arc, magmatic arc, and back-arc.
Study of Production-Injection Strategies for Sustainable Production in Geothermal Reservoir Two-Phase by Numerical Simulation Pratama, Heru Berian; Saptadji, Nenny Miryani
Indonesian Journal on Geoscience Vol 8, No 1 (2021): in-press
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17014/ijog.8.1.25-38

Abstract

The rapid pressure decline in liquid-dominated geothermal fields is a significant problem affecting the steam supply to the power plant. This study aims to understand the reservoir characteristics changes due to extraction of mass and heat from the reservoir through a numerical reservoir simulation under various strategies production-injection. The development of a liquid-dominated geothermal field model is assessed with various production strategies and injection strategies for the generation of 110 MW and 220 MW using a separated steam cycle. Thirty two production-injection strategies from a full factorial have been successfully carried out. The results show a low decrease for both reservoir pressure and decline rate for the steam cap and brine reservoir's production strategy combined with deep and dispersed injection strategy. From a simulation for 220 MW, the strategy for sustainable production is 25% from the steam cap and 75% from brine reservoir, dispersed, and deep reinjection with 9 make-up wells from the steam cap. The lowest decline rate after the 30th year is 0.5%, with Arps 1.0 exponent harmonic decline curve. The implementation of the production-injection strategy needs to be planned from the beginning of exploration or exploitation so that the strategy can be adjusted to changes in reservoir characteristics without causing problems.

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