Index of Active Tectonic Assessment: Quantitative-based Geomorphometric and Morphotectonic Analysis at Way Belu Drainage Basin, Lampung Province, Indonesia

The occurrence of subduction zones caused by the collision between the Eurasian-Western Indonesia Plate due to an increase tectonic, volcanic and magmatic activities along Sumatra Island. This study covers the area of Way Belu Drainage Basin, located near Bandar Lampung City, Lampung Province, southern part of Sumatra, Indonesia. The area composes of a complex geological structure as the result of tectonic activities. In this study, geomorphic indices assessment such as morphometric and morphotectonic quantitative analysis are undertaken to identify the Index of Active Tectonics (IAT). The morphometric analysis uses Drainage density (Dd) and Ratio of bifurcation (Rb). The value of Dd respectively from 1.45 to 4.05, Rb from  2 to 10. While the morphotectonic analysis uses basin shape index (Bs), valley floor width-valley height ratio (Vf), and asymmetry factor (AF). The value of Bs from 1.27 to 6.25, Vf   from 0.16 to 3.30, and AF from 22.73 to 83.77 in ranges which is derived average IAT value is 2.20. It may considered that at the Way Belu Drainage Basin has moderate to high tectonic activity. From the joint measurement results on the fracture zone express that the main pattern of faults has trend NWW-SSE, NE-SW, NNE-SSW, NW-SE, and W-E directions. Furthermore, based on the combination of the quantitative geomorphology indices assessment which is supported by remote sensing and field assessment shows that those features closely related to the Semangko Fault System with the NNW-SSE fault trend parallel to its fault

Tectonic Geomorphology of Upper Cimanuk Drainage Basin, West Java, Indonesia

The upper Cimanuk drainage basin is an inter-mountain basin. It is surrounded by volcanoes such as Mt. Tampomas, Mt. Guntur, Mt. Dano, Mt. Kamasan, Mt. Papandayan, and Mt. Cikuray. The objective of this research is to identify the degree of tectonic activity based on quantitative geomorphology analysis. Data are obtained from a topographic map, Digital Elevation Model, geological map, and field observation. Various morphometric variables are bifurcation ratio (Rb), drainage density (Dd), and mountain front sinuosity (Smf) index. The integrated analysis of morphometric and field data provides evidence of tectonic activity in Cimanuk drainage basin. Their streams have 1st until seventh order. The research area is proved to be an active tectonic area. This is confirmed by values of Rb, Dd, and Smf showing that some area in Cimanuk drainage basin has been affected by the tectonic activity. Rb values are ranging from 0.74 to 3.99, Dd values are ranging from 0.53 to 7.20, and Smf index area ranged from 1.2 to 1.6. These values can be classified into a medium class of tectonic activity level. The geological structure can be found in the middle to downstream of Cimanuk drainage basin and showed by primarily northwest-southeast trends. On the other hand, drainage pattern such as rectangular and trellis can reflect geological structures. Rectangular control is by joint and fault structure whereas trellis by dipping or folded sedimentary rocks. The Jatigede Reservoir is located in a strongly deformed area, so monitoring is necessary to reduce the impact of the disaster if some of the faults in the area are active again

Implication of Catchment Morphometric on Small River Discharge of Upper Citarik River, West Java

Upper Citarik River is the Inter Mountainous Valley of Volcanic Denudational Landform in the eastern part of Bandung basin, West-Java. The research area compounds of several degraded small catchments with very low water flow in dry season. This research aims  to understand the implications of morphometric characteristics (Slope, Cr, Dd, Hi) on average river flow discharge of small sub-catchments of Upper Citarik River. Discharge data collected based on measurements, while catchments morphometric identified and analyzed based on topographic map using GIS techniques.  Correlation graphs were used to understand the relationship among the morphometric parameter and the average river flow discharges. The result were as follow  the steeper the slope, the more elongated the shape of catchment, the more distant was the river density,  meaning the more younger the erosion cycle of the landform.  The younger the erosion cycle of the landform, the smaller was the average river discharge per areal unit of catchments

Remote Sensing Identification of Possible Meteorite Impact Crater on Ciletuh, West Java

Ciletuh is a geopark area in West Java that has a semicircle-shaped cliff called mega-amphitheater. Morphogenesis of the amphitheater is still unknown. One possible cause is a meteorite impact that triggered a mega slump. This study aims to collect the evidence of meteorite impact. It has significant value for the geology of Indonesia since this region not yet has confirmed impact crater. In this research, image analysis from satellite remote sensing is used for identification of meteorite impact geomorphology. An analysis based on DEM unveils a ring morphology, a possible clue of an impact crater. The depression zone surrounded by a circular shape with an uplift area in the middle resembles characteristics of the complex impact crater. Meandering Ciletuh river indicates a compression due to a slump towards the southwest. Reconstruction of possible position toward the northeast (before slump deformation occurred) shows a clearer possible meteorite impact crater. A ground checking of identified structure proves that a bowl-shaped morphology found at the possible impact crater. Some steep dip structures have found, these might be due to an impact that causes the orientation of the structure to be upright. A stone that resembles the shatter-cone is found in the mélange area. The mélange is believed as a product of a sea trench million years ago. By using meteorite impact theory, it is also possible that the mélange is a kind of impact breccia. This feature adds uniqueness to Ciletuh as a geopark

THE TECTONIC REJUVENATION IN JENEBERANG WATERSHED, SOUTH SULAWESI

Jeneberang watershed is located in the southern part of Sulawesi???s south arm. It covers the regencies of Gowa, Takalar, Maros and the city of Makassar. Jeneberang River has caused acute floodings in the coastal plain of Makassar. The flood is not merely due to the water debit but mostly related to the large amount of transported materials. To protect the worsening of the flood a series of debris control or sabo dams were built along Jeneberang River. However, the dams are quickly filled with the materials due to the intensive erosion and slumping.\ud The present study aims to reveal the cause of land and rock movements at the upper part of Jeneberang watershed. The morphometric analysis using satellite imageries and the measurement of morphologic elements such as river gradient, bifurcation ratio, river density, high-low ratio of the valley, sinuosity indices and river offset were carried out. The results show that active tectonics intensively takes place in the upper part of Jeneberang watershed. The rock slumping recently occurred in Bawakaraeng was one of the evidences of the tectonic rejuvenation (neotectonics) in the southern part of Sulawesi???s south arm

The geologic potentials of Riau Islands Province and its development design

Geologically Riau Islands is located in the topography of the old stadium erosion. The morphology is characterized by smooth hills with convex slopes and alluvial plain consisting of the erosion products. The morphology exhibits the remnants of peneplain that submerged at ca 13,000 BP now forming Sunda Shelf with the average depth of 120 meters. The irregular coast’s line of almost all the islands in Riau Islands characterized the submerged old morphologic stadium. The lithology consists of granites and metasediments. Granites contain various types of economic minerals. The weathered granites produce bauxite, kaolin and quartz sands. The metasediments are generally soft resulting in the formation of valleys suitable for agriculture and settlements due to the availability of surface and subsurface water. Irregular coastal line provides the bays for harbors. The geological potentials to be developed therefore consists of the provision of stable plain and resistance to landslide and earthquake, the bays suitable for various marine industries, granites for building materials, and base metals. The submarine hydrocarbon basins produce oil and gas. Geologically Riau Islands is very unique because it represents the remnants of the peneplain of Jurassic and Cretaceous age of about 63 to 181 years old now becoming the Sunda shelf which is the largest in the world. This region is very good when developed as an industrial area, trade, and marine tourism  Keywords: Riau Islands, geologic potentials, granites, submerge, marine touris

The geothermal potentials for electric development in Maluku Province

The characteristic of small to medium size islands is the limited amount of natural resources for electric generation. Presently the needs of energy in Maluku Province are supplied by the diesel generation units. The electricity distributes through an isolated grid system of each island. There are 10 separate systems in Maluku Province, namely Ambon, Namlea, Tual, Saumlaki, Mako, Piru, Bula, Masohi, Dobo and Langgur. From the geothermal point of view, this condition is suitable because the nature of the generation is small to medium and the locations are dispersed. The geological condition of Maluku Province is conducive for the formation of geothermal resources. The advanced utilization of geothermal energy in Maluku Province is in Tulehu located about 8 kilometers NE of Ambon. It is expected that 60 MW electric will be produced at the first stage in 2019. A total of 100 MW resources were estimated. Other places of geothermal potentials are Lauke and Tawen both located in Ambon Island with the potentials of 25 MW respectively. In Oma Haruku, Saparua and Nusa Laut the geothermal potentials were estimated to be 25 MW each. The total amount of geothermal energy in Maluku Province is thus, 225 MW which will contribute significantly to the needs of projected 184 MW in the year 2025

The Quantitative Geomorphology of Upper Citarik Watershed and Its Implication to the Flash Flood Potential

The research area is the Upper Citarik Watershed, located in the eastern Bandung Basin, West Java, Indonesia. This research aims to identify the quantitative geomorphology, especially the morphometry of the Upper Citarik Watershed, and its implication for the potential of flash floods. This research was conducted through a studio analysis with the support of thematic maps such as geological and slope maps. The parameters used in this morphometry calculation consist of linear aspects (stream order, stream length, mean stream length, stream length ratio, bifurcation ratio, and mean bifurcation ratio); areal aspect (drainage density, drainage texture, form factor, ratio of circularity, ratio of elongation, and length of overland flow); and relief aspects (watershed relief and relief ratio). The research results show that the Upper Citarik Watershed consists of 17 sub-watersheds that share relatively similar characteristics, including elongated shape with high relief and rather steep - steep slopes. It is predominantly composed of volcanic rocks and slow rising of flash flood. It shows that from a quantitative geomorphology perspective, the research area has high resistance to flash floods. Land use changes need to be a concern to prevent a significant decrease in the ability of land to deal with the flash floods

Integrating Remote Sensing and GIS Techniques for Accurate Mapping and Analysis of Oil Palm Plantation Distribution in Kelantan: A Case Study

The research conducted in Kelantan focused on analysing the distribution of oil palm plantations using remote sensing data and ArcGIS, a Geographic Information System (GIS) platform. The demand for accurate and up-to-date information on oil palm plantations has been increasing due to advancements in technology and the need for effective management of the environment. The study aimed to compare the distribution of oil palm plantations in 2016 and 2021 by using vegetation analysis techniques such as Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), and Soil-Adjusted Vegetation Index (SAVI). Remote sensing data from Landsat 8, specifically Bands 5, 4, and 2, were utilized to derive these vegetation indices. Ground-truthing data, obtained through GPS coordinates, were employed to increase the accuracy of the analysis. The expansion of oil palm plantations and non-oil palm areas was assessed using the Supervised Classification Maximum Likelihood method. The distribution data of oil palm plantations is highly sought after by oil palm plantation companies and serves public and private purposes, contributing to environmental monitoring and promoting sustainable practices