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Ivan Ferdian
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INDONESIA
Indonesian Journal on Geoscience
ISSN : 23559314     EISSN : 23559306     DOI : -
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.
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Articles 5 Documents
Search results for , issue " Vol 8, No 2 (2013)" : 5 Documents clear
Salinity Pattern in Semarang Coastal City: An Overview Rahmawati, Novi; Marfai, M. A.
Indonesian Journal on Geoscience Vol 8, No 2 (2013)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17014/ijog.8.2.107-118

Abstract

DOI: 10.17014/ijog.v8i2.160Semarang Coastal City is one of cities in Indonesia which has experienced a long-term salt intrusion. Land subsidence and groundwater exploitation were identified as main factors accelerated salt intrusion in this area. Extended salt intrusion into the land from year to year cannot be neglected. Salinity pattern and land use affected by this intrusion must be identified. Salinity pattern could be identified by electrical conductance content. The purposes of this research are: a) to define spatial electrical conductance map from 1995 to 2008 and b) to identify salinity pattern in each land use. Primary data set of electrical conductance measurement in 2004 and 2008 was performed. Secondary data set of electrical conductance was collected in 1995 and 2000. Electrical conductance mapping was assigned by point interpolation using GIS Environment. Land use classification was interpreted from topographical map and IKONOS using GIS Environment. Field check of land use was also done in the study area. Geologically, the area setting consists of Damar, Kalibiuk, and Breccias Formations, where the Damar Formation is the recharge source for groundwater in Semarang City. Based on the result, it can be concluded that the salinity content in groundwater increased from 1995-2008. In 1995, there was only 2.4% of brackish groundwater in Semarang Coastal City, but in 2008, most of area in that region was classified as saline. Land use conversion into built up area increased from 1998 to 2008. The area intruded by salt water increased within 1995, 2004, and 2008 periods. About 68 % of the area contained brackish water and most of the area were built up area in 1995. In 2004, no fresh groundwater found in Semarang Coastal City and the area of brackish groundwater reached 77% and about 23% was saline groundwater which 82% of the built up area included brackish groundwater. In 2008, approximately 55% of Semarang Coastal City was occupied by saline groundwater. About 51% of groundwater built up area was saline.
Hotwater Geochemistry for Interpreting The Condition of Geothermal Reservoir, Dieng Plateau Case, Banjarnegara-Wonosobo Regency, Central Java Ramadhan, Yuris; Channel, K.; Herdianita, N. R.
Indonesian Journal on Geoscience Vol 8, No 2 (2013)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17014/ijog.8.2.89-96

Abstract

DOI: 10.17014/ijog.v8i2.158The researched area, located in the Dieng Plateau, is included into the Holocene Dieng Volcanic Rock Unit. The regional structure in this area is originated from the major caldera with local fault having orientation of SE - NW. Surface manifestations found in the researched area are hot springs located in Bitingan, Sileri, Siglagah, Pulosari, Kaliputih, and Sikidang. Fumaroles occur in Candradimuka and Pagerkandang and mud pools are located in Sileri and Sikidang craters. Temperatures of the hot springs ranges from 43 C to 61 C, pH of 6 - 7, and their conductivity are of 38-78 MeV. The type of hotwater is a mixture of bicarbonate, sulfate, and chloride sulfate deriving from condensation of steam. Based on a relative composition of Cl-Li-B, the hot water is originated from four different reservoirs with different rock associations, while their reservoir temperatures vary from 225 C to 300 C.
Magma Supply System at Batur Volcano Inferred from Volcano-Tectonic Earthquakes and Their Focal Mechanism Hidayati, Sri; Sulaeman, C.
Indonesian Journal on Geoscience Vol 8, No 2 (2013)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17014/ijog.8.2.97-105

Abstract

DOI: 10.17014/ijog.v8i2.159The Volcano-Tectonic (VT) earthquakes occurring during September - November 2009 were analyzed. The result shows that the epicentres aligning in NE- SW direction coincided with the weak zone of Batur Volcano Complex. The focal zone is located at the depth around 1.5 - 5.5 km beneath the summit. Migration of magma was detected by ground deformation measured by GPS and focal mechanism. Mechanism of VT earthquake shows mostly normal fault types during the swarm in November 2009.
Morphostructural Development of Gunungsewu Karst, Jawa Island Tjia, H. D.
Indonesian Journal on Geoscience Vol 8, No 2 (2013)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17014/ijog.8.2.75-88

Abstract

DOI: 10.17014/ijog.v8i2.157Gunungsewu Karst (also known as Sewu karst in the literature) is synonymous with morphology of a carbonate terrain dominated by hills crowned by accordant-level tops that developed in a humid tropical environment by comparatively more rapid dissolution and denudation. In addition, the hills are sinoid to cone-shaped. Surface drainage is negligible compared to subsurface water flow. Abandoned channel segments and spatial arrangements of karst hills have been found to correspond with fracture patterns that are genetically associated with the regional compression direction of Jawa Island. Images derived from space platforms show many landform patterns that were neither known from ground-based nor from aerial photograph study. Landforms arranged in ring, multi-ring, spiral, polygonal, and long linear to serpentine patterns are common beside the expected depressions of dolines, poljes, and uvalas. The orientations of the long linear ridges appear to change systematically from those near the coast to those located inland. These linear ridges are interpreted as depositional fronts, most likely representing breaker zones. The youngest depositional ridge fronts, located nearest to the present shoreline, are parallel to the geological strike of Jawa Island. Toward the island’s interior, linear depositional fronts deviate in orientation by as much as 40o. This is now interpreted to have resulted from counterclockwise rotation of the Gunungsewu microplate since the late Middle Miocene. Similar CCW rotations are indicated by the paleomagnetic orientations of igneous rocks located farther east in the southern range of the island. Active tectonics is expressed in stage-wise net uplift of Gunungsewu whereas regional tilting appears negligible. Stacked and often paired river terraces (thus suggesting land uplift) have been used to relatively date paleoarcheological finds. Very recent uplift on the coast show up in lazy-V limestone notch profiles, and occasionally by stacked notches. At the Klayar coast, slight northward tilt of a few degrees are expressed as counter-regional inclination of a subrecent abrasion platform.
Maceral Characteristics and Vitrinite Reflectance Variation of The High Rank Coals, South Walker Creek, Bowen Basin, Australia Permana, Asep K.; Ward, C. R.; Gurba, L. W.
Indonesian Journal on Geoscience Vol 8, No 2 (2013)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17014/ijog.8.2.63-74

Abstract

DOI: 10.17014/ijog.v8i2.156The Permian coals of the South Walker Creek area, with a vitrinite reflectance (Rvmax) of 1.7 to 1.95% (low-volatile bituminous to semi-anthracite), are one of the highest rank coals currently mined in the Bowen Basin for the pulverized coal injection (PCI) market. Studies of petrology of this coal seam have identified that the maceral composition of the coals are dominated by inertinite with lesser vitrinite, and only minor amounts of liptinite. Clay minerals, quartz, and carbonates can be seen under the optical microscope. The mineral matter occurs in association with vitrinite and inertinite macerals as syngenetic and epigenetic mineral phases. The irregular pattern of the vitrinite reflectance profile from the top to the bottom of the seam may represent a response in the organic matter to an uneven heat distribution from such hydrothermal influence. Examination of the maceral and vitrinite reflectance characteristics suggest that the mineralogical variation within the coal seam at South Walker Creek may have been controlled by various geological processes, including sediment input into the peat swamp during deposition, mineralogical changes associated with the rank advance process or metamorphism, and/or hydrothermal effects due to post depositional fluid migration through the coal seam.

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