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91	Ocean Sciences	ABS-126
THE INFLUENCE OF RIVER DISCHARGE AND TIDE ON RESIDENCE TIME IN BERAU DELTA, EAST KALIMANTAN A. Tarya (a*), M. Ilham (b), S. Nurjaman (a) and F. A. R. Abdullah (a) a) Oceanography Research Group, Faculty of Earth Sciences and Technology, Bandung Institute of Technology b) Department of Oceanography, Faculty of Earth Sciences and Technology, Bandung Institute of Technology Abstract Residence time plays important role on biogeochemical processes in the coastal area. Understanding how long water remains in the delta and how quickly it is flushed is critical for estimating delta^s health. The present study aims to identify the influence of river discharge and tide on the residence time in the Berau Delta, East Kalimantan. The Delft3D-FLOW is applied to simulate the hydrodynamic and the particle tracking model. Eight scenarios have implemented based on river discharge and tidal variation. The comparison between model result and data observation for tidal elevation has a good agreement with Root Mean Square Error (RMSE) about 0.16 to 0.29 m and Mean Absolute Percentage Error (MAPE) value is 3.74 to 11.30%. Variation in river discharge has significant factor on the residence time. Simulation with the highest of river discharge (Q = 650 m3/s) result in the lowest residence time (8.36 days), whereas simulation without river discharge (Q = 0 m3/s) has the longest residence time (41.35 days). The difference of residence time between spring and neap tides is 3.20 days. The findings of this study enabled the identification of the most vulnerable areas within the delta as a function of river discharge. Keywords: Residence Time, River Discharge, Tides, Berau Delta Share Link | Plain Format | Corresponding Author (Ayi Tarya)

92	Ocean Sciences	ABS-128
The investigation of thermal fronts variability and its linkage to chlorophyll-a concentration in the Southeastern Tropical Indian Ocean Rangga Amrullah (a), Rahaden Bagas Hatmaja (b), M Restu Putra Sugianto (a), Shinta Ayu Kusumaningrum (a) a) Marine Science Study Program, Faculty Of Fisheries and Marine Science, Universitas Padjadjaran Jl. Raya Bandung Sumedang KM.21, 45363 Kabupaten Sumedang b) Research Centre for Climate and Atmosphere, National Research and Innovation Agency Jl. Dr. Djunjunan No.133, Pajajaran, 40173 Kota Bandung, Indonesia Abstract The spatial and temporal variability of the thermal fronts and their relationship with chlorophyll-a in the Southeastern Tropical Indian Ocean was studied using time series of MODIS daily Sea Surface Temperature (SST) and chlorophyll-a concentration (CHL) to investigate the locations of intense fish catch activities. An edge-detection algorithm operated on each SST image to identify thermal fronts in which a gradient of 0.3 C/pixel (&#8764- 0.02 C/km) was chosen following the sensitivity analysis. This study shows persistent and coherent spatial features between the datasets in their climatology and seasonal cycles. They exhibit distinct locations of maxima co-occurring between the 10 and 50 m isobaths in the continental shelf and slope region coincided with the areas of the VIIRS mapped fishing vessels cluster sites. The annual frequency dominates the seasonal cycles of thermal front density with a positive phase during May to November and peaks in September. These locations with a high probability of thermal fronts and high concentrations of Chlorophyll-a can be considered as the perennial potential fishing zone, with the boreal summer season being a more favorable period for fishing. Keywords: Thermal Front, Threshold, SIED, Potential Fishing Zone Share Link | Plain Format | Corresponding Author (Rangga Amrullah)

93	Ocean Sciences	ABS-130
Impact Of Tides On Eddies Formation In Sulawesi Sea. Dwiyoga Nugroho Research Center For Oceanography Abstract In this study, we investigate the effects of explicit tidal forces on numerical models of eddies formation in the Sulawesi Sea. The model used was ROMS CROCO, with a 1/36 degree horizontal grid resolution in 30 vertical layers. The effect of tides on eddies is examined by comparing the results of two simulations with and without tides forcing, namely TIDE and NOTIDE. Seasonal analyzes of the model are strongly correlated with satellite observational data and climatological results. Models with explicit tides show higher correlation values than models without tides. The model was run for three years and the effect of eddy kinetic energy on mean seasonal eddy kinetic energy was performed between two simulations. The eddy kinetic energy is smaller in non-tidal simulations. The effects of internal tides on eddies are analyzed using instantaneous results, and the vertical structural profiles of eddies are found to be different in the two simulations. Moreover, model results showed that internal tides provide additional mixing energy to the eddies. Keywords: Eddies, Internal tides, explicit tides, ROMS Share Link | Plain Format | Corresponding Author (dwiyoga nugroho)

94	Ocean Sciences	ABS-131
Indonesian Tsunami Generation Force in a Nutshell Afifah Hanum Amahoru, Ainur Ridho, Radikal Lukafiardi, Mizan Bustanul Fuady Bisri Cerdas Antisipasi Risiko Bencana Indonesia (CARI) research[at]caribencana.id Abstract The generation force of tsunami has been one of the important subjects within tsunami research and understanding the concept of tsunami generation can give insights about the propagation and inundation of a tsunami. For that purpose, this study has been utilizing peer literature reviews regarding tsunami hazard analysis compiled from CARI! search-engine system including publications that have been published in both International and Indonesian journals within the scope of Indonesian context. It is evident that one-third of the total research publication number specifically investigate the source setting of tsunami generation. Among those, Sunda Megathrust has become the most frequently investigated by researchers with 45.9% of tsunami generation publications due to its long, wide, and active tectonic area which stretched from North-western Sumatra until south of Bali Island. This has been followed by The Krakatau Volcano of The Sunda Strait by 18.9%, and the Palu-Koro fault in Sulawesi Island by 17.1%. Other tectonic sources capable of generating tsunamis in the eastern side of Indonesia and the intraplate fault are also studied, which accounts for the rest 18% of the tsunami generation force. Keywords: Tsunami, generation force, source setting, Sunda Megathrust, Krakatau Volcano, Palu-Koro fault Share Link | Plain Format | Corresponding Author (Afifah Hanum Amahoru)

95	Solid Earth Sciences	ABS-2
Geochemical and geological properties of tin related to ore deposits: A Review Aryo Dwi Handoko, Benyamin Sapiie, Syafrizal, Alfend Rudyawan Bandung Institute of Technology Abstract Tin have atomic number 50 and atomic mass 118,71, commonly found as cassiterite in nature. It is one of important element in low carbon technologies. Nowadays, tin utilized in broad application range from tin can to electronics. Despite many uses, tin only produced from limited areas. Because of broad application, understanding of tin in nature is important. Tin usually can be found together with wolfram, although it often occurs different spatially. Tin may occur in various ore deposit types such as greisen, vein, skarn, and placer. This article will describe the geochemical and geological properties of tin in nature, especially that related to ore deposits. Keywords: tin, geology, geochemistry Share Link | Plain Format | Corresponding Author (Aryo Dwi Handoko)

96	Solid Earth Sciences	ABS-5
Tectonic Geomorphology and Recent Activity of Haramachi Segment, Futaba Fault Zone, Northeast Japan. Anggraini Rizkita Puji Research Center for Geological Disaster, National Research and Innovation Agency (BRIN), Jalan Sangkuriang, Bandung 40135, Indonesia email: anggrainirizkita[at]gmail.com, angg026[at]brin.go.id Abstract Large crustal deformations have occurred in the Northeast Japan arc due to the earthquake off the Pacific coast of Tohoku (Mw 9.0) on March 11, 2011. Along with this massive earthquake occurred in the Japan Trench, the condition for failure on the Northeast Japan arc and surrounding active faults across Japan has changed. Identifying the detail deformation pattern is the key to minimizing the danger they pose. To date, the deformation pattern investigation in the Futaba fault zone is considered to be limited. Previous studies that delineated the fault trace was constructed based on interpretation from aerial topography and small scale topographic map which has significant limitation and uncertainty due to dense vegetation. This study examined the Haramachi segment focusing on the area where it is lacking of detail investigation and to validate the timing of the most recent faulting event more broadly. Geomorphic features associated with active fault deformation of the Haramachi segment have been examined by utilizing high resolution DEM and several types of topographic anaglyph images. Subtle surface expression of deformation associated with faulting such as deformed terrace surface, deflected drainages, deformed ridge, and linear valley can be identified. Several new fault strands are identified in this study, which is supported by fault outcrops found in the field that confirms the evidence of displacement. The most prominent fault scarp was observed near Uda River and Shiode Mountain area. The fault displaced the lowest fluvial terrace surface indicating most recent surface rupturing event. In attempt to validate the timing of the deformation, borehole survey on this terrace tread was conducted to collect the material suitable for radiocarbon dating. The soil organic material was analyzed using AMS method is yielding 3694 y.BP, which indicated the maximum elapsed time since the most recent surface rupturing event on the Haramachi segment. Keywords: Tectonic Geomorphology, Haramachi Segment, Futaba Fault Zone, Northeast Japan Share Link | Plain Format | Corresponding Author (Anggraini Rizkita Puji)

97	Solid Earth Sciences	ABS-6
Analysis of Eduroam Wireless Internet Service Coverage Using the Concept of Building Information Modeling (BIM) (Case Study : 2nd Floor of Labtek IX-C ITB Campus Ganesha) Gilang Vandita (a*), Vera Sadarviana (b), Asep Yusup Saptari (b) a) Geodesy and Geomatics Engineering Study Program, Faculty of Earth Science and Technology, Bandung Institute of Technology Jalan Ganesha 10, Bandung 40132, Indonesia *gilangvandita[at]itb.ac.id b) Geodesy and Geomatics Engineering Study Program, Faculty of Earth Science and Technology, Bandung Institute of Technology Jalan Ganesha 10, Bandung 40132, Indonesia Abstract Building Information Modeling (BIM) is an accurate representation of an object in digital form, which includes both spatial and non-spatial information in it. In order to its capabilities, BIM can be used to monitor facilites in an area, such as internet facility. This research aims to model and determine the factors that might affect Wi-Fi connectivity using the modeling concept of BIM. In this case, the factors related to the influence of room layout, spesifically to the distance from router to device and effect of obstruction- such as walls, doors, or windows on Wi-Fi signal transmission. The study area is modeled from point clouds data in the form of three-dimensional model. The modeling process is based on object-oriented modeling. Then, the 3D models is combined with Wi-Fi signal strength data. The integration results between them are displayed in the form of color visualization. The results show that room layout affects the Wi-Fi connectivity received by the device. More specific, the distance from router to device and the presence of obstruction between them reduce the quality of Wi-FI signal strength received by the device. Meanwhile, in order to object-oriented modeling concept, all phenomena being modeled must have a physical form. Hence, the Wi-Fi signal strength (which is a non-physical phenomenon) is modeled as an specific physical form. Keywords: BIM, Wi-Fi Connectivity, object-oriented, point clouds, signal strength Share Link | Plain Format | Corresponding Author (Gilang Vandita)

98	Solid Earth Sciences	ABS-9
Velocity Changes Associated to the 2019 Ambon Earthquake Using Ambient Seismic Noise Ahmad Amiruddin (a*), Nanang T. Puspito (b), David P. Sahara (b), Andri D. Nugraha (c), Zulfakriza (d) a) Earth Science Study Program, Faculty of Earth Science and Technology, Bandung Institute of Technology (ITB) *ahmadamir2626[at]gmail.com b) Global Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Bandung Institute of Technology (ITB) Abstract Seismic velocity changes which occurred before, during and after large magitude earthquake carry information about damage fault surrounding the area. Research focused in Ambon 6.6 Mw earthquake on September 26, 2019. We use ambient noise cross-correlation technique to compute empirical Green^s Function between station pairs from January to December 2019. We use doublet method to determine pertubation calculated in frequency domain by using Moving Windows Cross Spectrum in frequency between 0.1 to 1.0 Hz. Our results show no obvious significant velocity change before the mainshock. Velocity fluctuation average about 0.1% caused by nonisotropic of noise source around the area. Sudden velocity decrease occurred and reach average value of 0.33% in seven days after mainshock. After reach its lowest value, velocity gradually increased about 0.4% in 14 days. Velocity fluctuations about 0.2% also occurred for three months after the earthquake which may caused by the aftershocks around the earthquake epicenter. Following the large magnitude mainshock, velocity reduction may be induced by poroelastic opening and fractures due to deformation. While the velocity increase may caused by post-seismic relaxation due to elastic behavior and crack healing of the fault throughout the surrounding region. Keywords: velocity variation, ambient noise, earthquake, seismic Share Link | Plain Format | Corresponding Author (Ahmad Amiruddin)

99	Solid Earth Sciences	ABS-13
Volcanostratigraphy in the Lokon Volcano Area And Its Surroundings, North Sulawesi Kevin Gerald Senduk, Mirzam Abdurrachman Master of Geological Engineering, Faculty of Earth Science and Technology, Bandung Institute of Technology, Bandung Abstract Lokon Volcano is an active Quaternary volcano located in the Celebes - Sangihe Volcanic Arc. This study was conducted to explain the stratigraphy of volcanic rocks based on geomorphological analysis and petrological characteristics. Based on the geomorphological analysis, the Lokon Volcano area is divided into 9 geomorphological domains (Kayawu, Woloan, Kamasi, Irang, Lokon, Tatawiran, Galean, Kinilow, and Empung) separation is carried out based on topographic straightness patterns, reliefs, and topographic distribution patterns. Based on the field description, the lithology is divided into 18 geological units in the form of lava flows, pyroclastic flows, pyroclastic falls, and mudflows. Volcanology units of Lokon Volcano and its surroundings according to ISC (Indonesian Stratigraphic Code) are classified into Crown Tatawiran, Crown Kinilow, Crown Empung, and Crown Tou Lokon. Crown Kinilow is dominated by pyroclastic deposits with a scorous textured basalt composition, while Crown Empung is dominated by basalt lava flows. Crown Tou Lokon consists of 3 hummocks, namely Lokon which is dominated by pyroclastic flows, Irang which is dominated by lava flows with holohyalin textures, and Tompuluan which is dominated by pyroclastic falls. Lokon mountain volcanostratigraphic facies are divided into Tatawiran Central Facies, Tatawiran Proximal Facies, Tatawiran Central Facies, Tatawiran Proximal Facies, Kinilow Central Facies, Kinilow Proximal Facies, Kinilow Medial Facies, Empung Central Facies, Empung Proximal Facies, Lokon Central Facies, Lokon Proximal Facies, Lokon Medial Facies, Irang Central Facies, Irang Proximal Facies, Tompuluan Central Facies, and Tompuluan Proximal Facies. Keywords: Domain- Volcano- Lokon- ISC- Volcanostratigraphy. Share Link | Plain Format | Corresponding Author (Kevin Gerald Senduk)

100	Solid Earth Sciences	ABS-14
Multiparameter Land Subsidence Vulnerability Assessment through Satellite Imagery, GIS, and Spatial Data Integration Sinatrya Diko Prayudi (a*), Muhammad Rizki Maulana (b), Anggun Rahmawati (b), Daffa Arrofi (a), Sokhwatul Aghnia (c) a) Department of Geosciences, King Fahd University of Petroleum & Minerals, Dhahran, Kingdom of Saudi Arabia *g202114310[at]kfupm.edu.sa b) Department of Geological Engineering, Diponegoro University, Semarang, Indonesia c) Department of Geological Engineering, Gadjah Mada University, Yogyakarta, Indonesia Abstract Land subsidence is a substantial issue today, particularly in some regions where it has the ability to interrupt future development, halt the process, and even modify the development plan. In general, this study focuses on updating current knowledge on land subsidence and performing risk assessments using a case study in Semarang City, Central Java, where land subsidence is a serious problem. Several satellite imageries, such as Sentinel-1 and Sentinel-2, are used as databases in this work, with various target analysis and GIS methods used to handle and alter the data. Sentinel-1^s radar data, along with the displacement analysis approach of Differential Interferometry Synthetic Aperture Radar (DInSAR), is primarily used to provide a snapshot of the present state of land subsidence under this area in 2022. The result demonstrates the variance of vertical displacement values ranging from -7.7 to 6.65 cm with subsidence spread mostly in the northern region, using two datasets with 60-day intervals between January and March. Using a combination of the Normalize Difference Vegetation Index (NDVI) and the Normalize Difference Built-in Index (NDBI) to create Built-up Index (BU) data, the Sentinel-2 data with optical-based images were then used to map the human-made feature and expansions, notably buildings. Each piece of information considered multiparameter was afterward overlapped to build a vulnerability map, while also considering the geological dataset and validated by ground verification. This finding will be presented to the section of the city that can help support the city^s future growth in terms of its vulnerability to land subsidence dangers. Keywords: Geographical Information System- Land Subsidence- Remote Sensing- Semarang City- Vulnerability Assessment Share Link | Plain Format | Corresponding Author (Sinatrya Diko Prayudi)

101	Solid Earth Sciences	ABS-17
First Appearance Datum (FAD) of planktonic foraminifera Boliella adamsii as the Pleistocene - Holocene boundary marker on the sea around Sumba Island Ryan Dwi Wahyu Ardi (a*, b), Aswan (a), Khoiril Anwar Maryunani (a), Eko Yulianto (c), Purna Sulastya Putra (a, c), Septriono Hari Nugroho (a, c) a) Geological Engineering Study Program, Faculty of Earth Science and Technology, Institut Teknologi Bandung Jl. Ganesha No. 10, Bandung 40132, Indonesia *dwa.ryan[at]students.itb.ac.id b) Agrotechnology Study Program, Faculty of Science and Technology, Universitas Nahdlatul Ulama Purwokerto Jl. Sultan Agung No. 42, Purwokerto 53144, Indonesia c) Research Center for Geological Disaster, National Research and Innovation Agency Jl. Sangkuriang Kompleks LIPI Bandung 40135, Indonesia Abstract The expensive cost of Accelerator Mass Spectrometer radiocarbon dating (AMS 14C), the main tool for geochronology in Late Pleistocene - Holocene paleoclimate and paleoceanography study using marine sediment cores, hinders Indonesian researchers to produce competing research outputs. The first and last occurrences of foraminifera taxa which have been applied as Pleistocene - Holocene boundary markers in previous highly cited studies, indicated inconsistent ages in the Late Quaternary marine sediments of the Indonesian region. Quantitative foraminifera determination and oxygen isotope analysis of planktonic foraminifera (\(\delta^{18}\)Oc) species Globigerinoides (Gs.) ruber have been carried out on sediment core ST10 (off south Sumba) and ST14 (Sumba strait). \(\delta^{18}\)Oc Gs. ruber was correlated to Greenland Ice Core Chronology 2005 (GIC05) to determine the depth of the Pleistocene - Holocene boundary (~11650 BP) on core ST10 and ST14. Pleistocene - Holocene boundary depth on the core ST10 (30.5 cm) and ST14 (28.5 cm) are nearly coeval with the First Appearence Datum (FAD) of planktonic foraminifera Boliella adamsii, which at 34.5 cm depth in core ST10 and at 26.5 cm in core ST14. This indicated the practicality of Boliella adamsii FAD as a Pleistocene - Holocene boundary marker on the sea around Sumba, in case radiocarbon ages and proper \(\delta^{18}\)Oc data are unavailable. Further study with a similar method is needed to confirm the practicality of Boliella adamsii FAD as a Pleistocene - Holocene boundary marker in other Indonesian regions. Keywords: biostratigraphy, marine sediment, micropaleontology, Late Quaternary Share Link | Plain Format | Corresponding Author (Ryan Dwi Wahyu Ardi)

102	Solid Earth Sciences	ABS-20
Petrogenesis of volcanic rocks on Karimunjawa Islands, Central Java, Indonesia Mirzam Abdurrachman (a*), Radhitya Eka Pradipta (a), Wildan Nur Hamzah (a,b), Emmy Suparka (a) a) Geological Engineering Study Program, Bandung Institute of Technology, Indonesia *mirzam[at]gl.itb.ac.id b) Akita University, Japan Abstract The Karimunjawa Islands (KI), Central Java, Indonesia is located at the southeastern margin of Sundaland. In this study we examined the petrology and geochemistry of volcanic rocks from Parang Island (PI) (6.5-5.6 Ma) and Genting Island (GI) (2.5-1.8 Ma). The link between Genting and Parang Islands with plate subduction is not simple since there are subduction^s angle changing along the Java Trench. The complexity might be related to the composition of overriding plate, the age of subducted plate and also by the presence of micro continent. This study aims to better understand the structure beneath KI and tectonic evolution of southeastern margin of Sundaland. The lavas from both Genting and Parang are basalt in composition with TiO2 ranges 1.51-2.65 % Wt, La/Yb > 7 and Nb/La>0.91. This condition implies a common magma genesis related to the upper mantle plume on non subduction setting. The presence of mantle upwelling in the upper mantle might be caused by the thinning of subducted slab beneath KI. New tectonic scenario in this area is presented. Keywords: Petrology- Geochemistry- Karimunjawa Islands- Central Java- Indonesia Share Link | Plain Format | Corresponding Author (Mirzam Abdurrachman)

103	Solid Earth Sciences	ABS-22
PETROLOGY, MINERALOGY, AND GEOCHEMISTRY OF VOLCANIC ROCKS IN THE GALUNGGUNG VOLCANO, TASIKMALAYA, WEST JAVA Fariha Elsyanaya Danti Putri (a*), I Gusti Bagus Eddy Sucipta (b), Idham Andri Kurniawan (b) a) Laboratory of SEM EDS UPP Chevron Bandung Institute of Technology, Indonesia b) Petrology, Volcanology, and Geochemistry Research Group, Geological Engineering, Faculty of Earth Science and Technology Bandung Institute of Technology, Indonesia Abstract Galunggung Volcano is one of the volcanoes in West Java with high eruption rate. This research aims to determine the petrological, mineralogical, and geochemical characteristics, rock-forming magma during 50.000 BP until recent. The primary data was used 29 samples for petrographically analysis and 5 samples for mineral chemistry. The secondary data is 53 data samples of geochemical and 5 data samples of mineral chemistry from the previous study. The result show that the eruption of Galunggung Volcano is divided into 4 eruption periods, 50.000 to 10.000 BP, 4.200 more or less 150 BP, 1822 to 1894 to 1918, and 1982 to 1983 period consisting of 1, 2, and 3 phases. The 50.000 to 10.000 BP period produced basalt to basaltic andesite (SiO2 47 to 56 wt%) containing fosterite composition of olivine (Fo64 to 70) and An in plagioclase (An46 to 67). The 4.200 more or less 150 BP period produced basalt to basaltic andesite (SiO2 51 to 55 wt%) containing fosterite composition of olivine (Fo62 to 64) and An in plagioclase (An50 to 71). The 1822, 1894, and 1918 periods produced basalt to basaltic andesite (SiO2 51 to 55 wt%) containing An in plagioclase (An39 to 70). At the beginning of phase 1 in the 1982 to 1983 period produced basaltic andesite to andesite (SiO2 53 to 57 wt%), phase 2 produced basalt to basaltic andesite (SiO2 50 to 51 wt%) containing fosterite composition of olivine (Fo76 to 90) and An in plagioclase (An47 to 70), phase 3 produced basalt to basaltic andesite (SiO2 49 to 54 wt%) containing fosterite composition of olivine (Fo70 to 87) and An in plagioclase (An66 to 91). The spider and tectonic discriminant diagrams show the tectonic setting of Galunggung Volcano related to the subduction process which is contaminated by continental and oceanic crust. The activity history of Galunggung Volcano was started by the initiation of basaltic magma injection (SiO2 47 wt%) with tholeiitic to calc alkaline affinity in differentiated magma at 50.000 to 10.000 BP period. In the 4.200 more or less 150 BP period, the vent moved to the southeast flank, named Galunggung Volcano and magma differentiation was still going on. In the 1822, 1894, and 1918 periods, the differentiation process named crystal fractionation continues simultaneously with injection of basaltic magma. In phase 1 of 1982 to 1983 period, a new generation of low Mg magma moved diapirically influenced by crystal fractionation en route to the surface. So, phase 1 was the most fractionated magma that erupted first, followed by the less developed magma in phase 2 and the unmodified high Mg magma that erupted in phase 3 in 1982 to 1983 period. Keywords: volcanic activity, magma differentiation, Galunggung Volcano, eruption period Share Link | Plain Format | Corresponding Author (Fariha Elsyanaya Danti Putri Putri)

104	Solid Earth Sciences	ABS-23
VOLCANOSTRATIGRAPHY OF NANGERANG REGION AND SURROUNDING AREAS, A PREELIMINARY STUDY OF POROSITY IN TERTIARY VOLCANIC ROCKS MUHAMMAD IMRON HASANI, MIRZAM ABDURRACHMAN, IDHAM ANDRI KURNIAWAN, TAUFIK ISMAIL INSTITUT TEKNOLOGI BANDUNG Abstract Recently many volcanic reservoirs are produced and become proven reserve for hydrocarbons. However, many of these exploration process in volcanic environment faces major obstacle in understanding the reservoir itself. Being different from sedimentary reservoir, volcanic reservoir has different approach of study and character. In order to get more understanding, analogs outcrops are being used. Analogs are being used to help understand the process of porosity formation and their diagenetic process. The location of outcrops analog is located in Nangerang, Sukabumi Regency . The methods are volcanostratigraphy and petrographyical analysis. Volcanostratigraphy analysis is carried out to determine the position, geometry, and deposit evolution at its central, proximal, medial, and distal positions. 23 samples of petrography are carried out to determine the porosity type and their diagenetic process. The result shows 11 (eleven) volcanostratigraphy units, consisting of Basement Rock (1 unit, sedimentary rock, Jampang Khuluk (1 unit, composite of lava and pyroclastic breccia), Nangerang Khuluk (2 units, tuff and composite of lava and pyroclastic breccia), Bantarpanjang Khuluk (6 units, pyroclastic breccia) and Resedimented Unit (1 units, volcanic breccia). Using references and foraminifera fossils analysis, the age of Basement Rock is Early Miocene Age and equivalent with Jampang Formation. Other volcanic units are estimated to be Late Miocene-Pliocene based on previous studies. The petrographical analysis shows that the matrix of pyroclastic breccia (flow deposit) and tuff (fall deposit) in all samples have primary porosity, composed of intergranular or intragranular or both with the total of visible porosity less than 5%. The appearance of dissolution/vuggy enhances the porosity of samples with the total of visible porosity 5-18%. The genesis of dissolution in the samples comes from weathering and alteration. However, some of samples shows that the alteration process decreasing the visible porosity because of quartz mineral filling. Keywords: Volcanostratigraphy, Jampang, Resevoir Analog, Porosity, Diagenesis Share Link | Plain Format | Corresponding Author (Muhammad Imron Hasani)

105	Solid Earth Sciences	ABS-26
PETROGENESIS OF ADANG AND TALAYA VOLCANIC ROCKS, IN THE MAMUJU AREA AND ITS SURROUNDING, WEST SULAWESI M. Arafat Zaidani (1), Bambang Priadi (2), I Gusti Bagus Eddy Sucipta (2), Very Susanto (2), Asep Saepuloh (2) (1) Geological Engineering - Bandung Institute of Technology, Indonesia (2)Petrology, Volcanology, and Geochemistry Research Group, Geological Engineering, Faculty of Earth Science and Technology - Bandung Institute of Technology, Indonesia Abstract The Adang Volcanic and Talaya Volcanic complex located in the Mamuju area are ancient volcanic complexes of the Neogene period. These two complexes consist of pyroclastic, volcaniclastic, and basic-intermediate lava containing the main modal minerals of leucite and clinopyroxene, making these rocks unique and rarely found in Indonesia. This study aims to determine the petrological and geochemical characteristics as well as the tectonic setting of rock formation. The rocks are generally porphyritic and vitrophyric in texture with various rock types as a result of magma differentiation. The Adang Volcanic Lava is composed of trachyandesite, tephriphonolite, trachyte, phonolite, and leucitite. Talaya Volcanic Lava is composed of basalt and trachybasalt rocks. Based on geochemical content, rocks have high alkalinity with wide range concentrations of K2O (0.27 - 10.12%), Na2O (0.54 - 11.06%), and total alkali (4.6 - 12.6%), as well as evidenced by the presence of feldspathoids. Rocks are divided into three groups, sodic, potassic, and ultrapotassic. The ultrapotassic rocks have similarities with Group III (Active Orogenic Zone) and Group I (Lamproite). The intensive enrichment of incompatible elements such as Rb and Th as well as the negative Nb and Ti anomalies reflect that magma derived from mantle metasomatism and is associated with subduction events. The genesis of the rock occurred in the tectonic setting of alkaline arc magmatism or continental extensional zone which was formed after the collision of the Banggai-Sula microcontinent with West Sulawesi. This process is also indirectly influenced by pre-collision subduction of the oceanic lithosphere. Keywords: Petrogenesis- Mamuju- Alkali- Geochemistry- Potassic- Ultrapotassic- Alkaline Arc. Share Link | Plain Format | Corresponding Author (M. Arafat Zaidani)

106	Solid Earth Sciences	ABS-31
DESIGN AND PRELIMINARY RESULTS OF DEBRIS FLOW ANALOG MODEL WITH LABORATORY SCALE, CASE STUDY BENTARSARI SUBWATERSHED Imam A. Sadisun (a, b*), Indra A. Dinata (a), and Lambok M. Hutasoit (a) (a) Applied Geology Research Group, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung, Indonesia *sadisun[at]gmail.com (b) Research Centre for Disaster Mitigation, Institut Teknologi Bandung, Indonesia Abstract Bentarsari Subwatershed is located at Brebes Regency administrative area, Central Java. This subwatershed is bounded by hills composed by volcanic breccia of Kumbang Formation (Tpk) and the bottom of the basin is dominated by sedimentary rocks. Volcanic breccias have a relatively old age and appear to have more intensive weathering process so they are more susceptible to landslides. The main materials for debris flow modeling are moderate to highly weathered volcanic breccia unit and completely weathered volcanic breccia to residual soil. The rainfall scenarios will used 50 mm/day (lowerbound of heavy rain class), 100 mm/day (lowerbound of very heavy rain class), and 150 mm/day (lowerbound of extreme rain). Laboratory scale analog model design with software can already model the movement of solid materials. An actual laboratory scale analog model has been made with 1.75 m high, 2 m long, and 1 m wide dimensions. The simulation uses a spherical material with a density of 1.84 g/cm3. The density value is taken from average laboratory results of completely weathered volcanic breccia to residual soil because which dominated the debris flow events in Bentarsari Subwatershed. The simplification process is carried out on spherical material with 4 cm and 2 cm diameter to depict moving material. The volume of solid material used in the simulation is 0.07 m3 while the volume of liquid is 0.03 m3. When the analog model is tilted 50 degree, the slip plane which forms then expands to the rear of slope, the flowing material moving downwards, colliding with the previously deposited material, forming a flow which bends slightly to the left of slope. Keywords: debris flow, analog model, deterministic modelling Share Link | Plain Format | Corresponding Author (Indra Andra Dinata)

107	Solid Earth Sciences	ABS-33
ABILITY ANALYSIS OF THE POINT-TO-PLANE METHOD ON ITERATIVE CLOSEST POINT (ICP) ALGORITHM IN INCREASING ACCURACY RESULTS OF THE EARTH^S SURFACE POINT CLOUD STRIP ADJUSTMENT Monica Maharani(a*), Riyas Syamsul Arif,(a) Harintaka(b) a) Universitas Pembangunan Nasional Veteran Yogyakarta b) Universitas Gadjah Mada, Yogyakarta Abstract Point-to-plane in the Iterative Closest Point (ICP) algorithm is a registration method in 3D Machine Learning that is reliable in increasing the accuracy of registration of non-topographic objects. Research is necessary when this method is applied to topographic objects which have different characteristics from nontopographic objects, especially in the variety of objects. This study was conducted to examine the reliability of the point-to-plane method for registering point cloud LiDAR on real-world topographic objects as the implementation of strip adjustment. This research begins with building a program to perform strip adjustment. The program uses Iterative Closest Point (ICP) algorithm with a point-to-plane registration method. The program is developed on Phycharm as an Integrated Development Environment (IDE) using Python Language. Then, the program is used to perform a strip adjustment process on 2 scene point cloud data from the acquisition of an Unmanned Aerial Vehicle with a Light Detection and Ranging (LiDAR) sensor. The result of the strip adjustment on the program is compared with the strip adjustment result using the point-to-point method on CloudCompare software. The comparison is to determine the reliability and accuracy of the registration result from the point-to plane method through the value of the Root Mean Square Error (RMSE), transformation matrices, fitness, correspondence, and visual appearance. In addition, the comparison is also done on each type of land cover on the earth^s surface, like roof, vegetation, roads, and ground. This step is done to test the performance of the point to-plane method on each type of land cover on topographic data. In this study, it is proven that the point-to-plane registration method has better accuracy than the point-to-point in registering point cloud data on the earth^s surface. The RMSE value using the point-to-point method is 8.71 centimeters, while the point to-plane method is 1.53 centimeters. The RMSE value and transformation matrix on the point-top-plane are more minor than point-to-point. The point-to-plane method produces a fitness value of 0.001 meters with a total correspondence of 1054 points. For each type of land cover on the earth^s surface, the point-to-plane method has succeeded in making fitness on the combination of data. Keywords: point-to-plane, strip adjustment, ICP, machine learning Share Link | Plain Format | Corresponding Author (Monica Maharani)

108	Solid Earth Sciences	ABS-40
GEOLOGY AND HYDROTHERMAL ALTERATION OF THE KUTAWARINGIN, SOREANG SUB-DISTRICT, BANDUNG REGENCY, WEST JAVA Daniel Jefri Hasudungan Mirzam Abdurrachman Melky B. Rondonuwu Sekolah Tinggi Teknologi Mineral Indonesia Institut Tekonologi Bandung Abstract The need for metal minerals to become raw materials increases along with technological advances. Therefore, exploration is needed to increase metal mineral reserves in Indonesia. The research area is administratively included in the Soreang Sub district, Bandung Regency. In this study, we combine field geology with petrographic and mineragraphic analysis. The rock units found in the study area from old to young are volcanic breccia, andesite lava and tuff which are intruded by porphyritic andesite. The geological structure that develops in the study area seen from the DEM map is divided into two main strains which are northeast west and northwest southeast. The alteration zones that develop in the study area are divided into argillic zones associated with kaolinite, illite and smectite minerals. Sub propylitic zones associated with chlorite, illite and carbonate minerals. Phyllic zones associated with sericite, chlorite and quartz minerals. Based on the presence of these minerals, it is interpreted that the alteration zone in the study area was formed at temperatures between 200 to 320 degrees celcius with the formation environment having a neutral pH. Mineralization that develops in the study area is in the form of veinlets mineralized by pyrite, chalcopyrite, sphalerite and galena. The mineral deposit type of the study area is low sulfidation epithermal type. Keywords: Geology, Hydrothermal Alteration, Mineralization Share Link | Plain Format | Corresponding Author (Daniel Jefri Hasudungan)

109	Solid Earth Sciences	ABS-41
GEOLOGY AND ALTERATION STUDY of GARUMUKTI REGIONAL PAMULIHAN SUB-DISTRICT, GARUT DISTRICTS GARUT JAWABARAT PROVINCE Raden Reza Dwi Yana, Mirzam Abdurrachman, Melky B. Rondonuwu dan Daniel Jefri H. Sekolah Tinggi Teknologi Mineral Indonesia Institut Teknologi Bandung Abstract This study aims to identify and examine geological aspects, in the form of Lithology, Geological Structure and Alteration Zone. The research area is located in Garumukti and its surroundings, Pamulihan District, Garut Regency, West Java Province. Tectonically, it is included in the volcanic arc zone of the southern part of western Java, in the study area there are rocks of late Miocene to Holocene age divided into nine units namely the Sembung Lava Unit, Sembung Pyroclastic Flow Unit, Kendeng Lava Unit, Mandalagiri 1 Lava Unit, Mandalagiri Lava Unit 1, Mandalagiri 2 Lava Unit, Mandalagiri 2 Pyroclastic Unit, Diorite Intrusion Unit and Papandayan Lava Unit. The geological structure of the study area has seven faults in Late Pleistocene faults, namely Cipanyairan Left Fault, Cipaningeu Right Fault, Cicadas Left Fault, Ciangkrong Right Fault, Cibitung Normal Left Fault, Cipeundeuy Normal Left and Sawer Normal Left Fault. The research area is an area that has three alteration zones, namely Advanced Argillic Zone (Quartz, Kaolinite and Carbonate), Subpropylithic Zone (Quartz, Chlorite, Illite and Carbonate) and Phylic Zone (Sericite, Quartz and Chlorite). Judging from the mineral associations, it is formed at a temperature of 200 to 320 Celsius which indicates a low sulfidation epithermal system. There are also metallic minerals in the form of pyrite, chalcopyrite, galena and sphalerite, which are formed at temperatures of 200 to 250 Celsius with a pH of 4 to 5. The distribution of Alteration zones in the study area is generally controlled by lithology in the form of andesite and breccias as well as horizontal fault structures that arise as a result of subduction the Eurasian plate beneath Indo-Australian plate. Keywords: Garumukti, Alteration, Low Sulfidation Epitermal Share Link | Plain Format | Corresponding Author (Raden Reza Dwi Yana)

110	Solid Earth Sciences	ABS-46
Geomorphological Reconstruction of the Pre-Caldera Edifice of Raung Volcano, East Java, Indonesia Firman Sauqi Nur Sabila, Mirzam Abdurrachman, Asep Saepuloh, Idham Andri Kurniawan Geological Engineering Study Program, Faculty of Earth Science and Technology, Institut Teknologi Bandung, Jl. Ganesha No. 10, Bandung 40132, Indonesia Abstract Mount Raung is a stratovolcano with a 2.2 km wide caldera with an unknown eruption history. This volcano, located in East Java, Indonesia, is one of the most active volcano in Indonesia and became the highest (+3344 masl), youngest, and most active volcano growing on the southwest flank of the Ijen Volcano Complex. The summit of this volcano is devoid of vegetation and has a truncated cone morphology which represents a caldera with a depression as deep as 500 m. As a stratovolcano, the peak of this volcano is estimated to be higher before the caldera-forming eruption occurs. The information of original morphology of this volcano is important to interpret the pre-caldera eruptive activity. Therefore, this research was conducted to reconstruct the morphology of the Mount Raung pre-caldera edifice. The reconstruction using a basic volcanic geomorphological principles in stratovolcano type. The model of the original morphological condition of Mount Raung edifice before the caldera was formed was carried out using digital elevation model data. Reconstruction of the top of the volcano is done by drawing lines based on the ridges on the caldera slope which represent the original topography that has not been eroded. The ridges that have been obtained using tracking with the Global Mapper software are then displayed in an elevation-to-distance plot. The results of the plot are then drawn using a regression method to obtain an estimate of the peak point. A total of eight ridge lines were analyzed to obtain eight forecast points for the summit position. Based on these points, contour lines are then made which are then converted into a DEM of the top of the volcano edifice. Based on the reconstruction, the pre-caldera summit height of Mount Raung was obtained about 3761 masl. The generated paleotopography of pre-caldera has been used to calculate the volume of the lost materials. Accordingly, we calculated that the lost volume of the caldera-forming eruption is about 1.28 km3. Keywords: Raung, Geomorphology, Edifice, DEM, Pre-Caldera. Share Link | Plain Format | Corresponding Author (Firman Sauqi)

111	Solid Earth Sciences	ABS-52
INVENTORY AND QUANTITATIVE ANALYSIS ON GEOSITE TO SUPPORT THE POTENTIAL OF GEOTOURISM IN MAGETAN AREA, EAST JAVA Muhammad Reinaldy Ramli (a), Mirzam Abudurachman (a), Johan Arif (a), Derry Apriansyah (a) a) Institut Teknologi Bandung Abstract Magetan Regency, which is located in East Java Province, has a geological diversity that can be developed into geotourism. Compared to cultural tourism, geotourism is less studied and further researched. So this study aims to assess the geological potential scientifically at each site in Magetan Regency. This research was conducted with an inventory by conducting an assessment and analysis of tourist attractions. Parameters used to quantitatively assess geological sites based on scientific value, educational value, tourism value, and risk of degradation. The results of the geotourism analysis will be processed into geosite and geotrack recommendations. The results of satellite imagery analysis and field observations show that the research area is divided into seven geomorphological units, Bancak Isolated Hill, Bungkuk Isolated Hill, Lawu Lahar Plain, Blego Volcano Unit, Lawu Volcano Unit, Lawu Tua Volcano Unit, and Old Lawu Lahar Unit. The research area includes 13 geological units, the oldest is a Tertiary volcanic rock sequence in the Nglanggran Formation and the youngest is a volcanic rock originating from the Quaternary volcano. Based on analysis results from 9 geosites, Magetan Regency has 2 geosites that have the highest value, Sarangan Lake which located in the west of the study area and Mount Blego which is in the south. Both geosites have the potential to be developed and become priority tourist attractions in Magetan Regency because those geosites have a high total scientific, educational and tourism value as well as the potential risk of degradation that can be reduced. The order of geotrack is based on the age of the oldest units starts from Mount Bancak and Sejok Springs, to the west towards Mount Blego and Mount Bungkuk, then towards the age of the youngest units, Mount Lawu Tourism such as Mojosemi Forest Park, Genilangit, Highland Wonomulyo, Tirtosari Waterfall, and Sarangan Lake Keywords: geotourism, geosite, geotrack, Magetan, inventory, quantitative analysis Share Link | Plain Format | Corresponding Author (Muhammad Reinaldy Ramli)

112	Solid Earth Sciences	ABS-53
ARCHITECTURAL AND CHARACTERISTIC BASEMENT FRACTURES IN THE WESTERN INDONESIA Benyamin Sapiie, Alfend Rudyawan, Indra Gunawan Prodi Teknik Geologi ITB Abstract Fractured reservoirs present challenging problems to the petrophysicist and reservoir engineer. In fractured reservoirs, the oil and gas occur within an extensive fracture network on various scales rather than within the matrix porosity of the formation. As a result, fractured reservoirs are more complex and expensive to evaluate than conventional ones. Therefore, an outcrops study can help ramify some of the issues, particularly regarding physical properties, geometry, and distributions of the fractures. This paper delivers the results of extensive fieldwork of fractures characterization and mapping in the basement rocks, particularly granitic complex across Sumatra, Batam, and Bangka Island. The study covers detailed structural analysis, petrography, and porosity measurements. as well as comparing the results to several basement fractures reservoir fields in the Central and South Sumatra Basin. Fractures are observed in granite to granodiorite, andesite to basalt, metamorphic rocks such as phyllite, slate, metasediment, and sedimentary rocks, including limestone, sandstone, and mudstone. Fractures attributes such as length, spacing, and apertures were observed systematically using scanline and window mapping. In addition, complex cross-cutting relationships were carefully mapped to have a better understanding in terms of deformation sequences. The primary orientation varies from each lithology and age. However, the majorities are NE - SW, NW - SE, E - W, and N - S trends, mostly like known pre-existing faults orientation with the basement rocks in the subsurface. Within the same tectonic block, fracture density tends to be greater in metamorphic rocks, igneous rocks, and sedimentary rocks. It also varies within the same lithologies with different ages, indicating different phases of tectonic deformation. Fracture intensity and density also decrease relatively from the eastern part of Sumatra to the western part. However, they are comparably high in the proximity of the suture zone and regional faults. Based on the measurements on granitic rocks, fracture intensity and density tend to be higher in rhyolite or aplite than in granite. This evidence specifies the role of grain size and textural composition on intensity and density and that rocks with the same composition will have higher intensity in the finer-grained rocks. Fracture density numbers on granitic rocks are higher than those observed in both outcrop and subsurface, indicating lithology control dominates fracture behaviors. Keywords: Fractured Basement Reservoir, Fracture density, Fractures intensity Share Link | Plain Format | Corresponding Author (Benyamin Sapiie)

113	Solid Earth Sciences	ABS-62
VERTICAL ACCURACY ASSESSMENT IN MINING AREA USING MULTI-GEODETIC SENSORS (1) Rizqi Aulia, (2) Irwan Gumilar, (2) Brian Bramanto (1) Geodesy and Geomatics Engineering Study Programme, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung (2) Geodesy Research Group, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung Abstract Survey activity has an important role in mining industries. The development of Mapping technology has increased rapidly in recent times that enables mining business to increase productivity in mining. The use of the terrestris method that has been used so far has several disadvantages, including the aspect of work safety and the length of processing time. The study, aims to analyze the vertical accuracy from the Unmanned Aerial Vehicle Light Detection and Ranging (UAV LiDAR) method and UAV Photogrammetry method that enable us to improve the work safety and increase the productivity. This study, focuses on assessing the vertical accuracy of each sensor used. The reference data used in this research is Terrestrial Laser Scanner (TLS) point clouds data. Based on the comparisons, the Root Mean Square (RMS) of differences for LiDAR and photogrammetry was estimated to be 5 cm and 2 cm, respectively. Thus, both UAV LiDAR and UAV photogrammetry comply with the accuracy standards for measuring Mining Pit situations and ASPRS standards (American Society for Photogrammetry and Remote Sensing (ASPRS) in 2014. Keywords: Point Clouds, UAV LiDAR , UAV Photogrammetry, Post Processing Kinematic (PPK), RMS Share Link | Plain Format | Corresponding Author (RIZQI AULIA)

114	Solid Earth Sciences	ABS-64
VOLCANOSTRATIGHRAPHY AND PETROGENESIS OF SADAKELING KARAHA COMPLEX, TASIKMALAYA DISTRICT, WEST JAVA PROVINCE Azrie Ezziat Putera Muhammad (a*), Mochammad Nugraha Kartadinata (b), Mirzam Abdurrachman (c), Wilfridus FS Banggur (d) a) Department of Geological Engineering, Bandung Institute of Technology Jalan Ganesha 10, Bandung 40132, Indonesia *azriezziat20[at]gmail.com b) Center for Volcanology and Geological Hazard Mitigation Jalan Diponegoro 57, bandung 40122, Indonesia c) Department of Geological Engineering, Bandung Institute of Technology Jalan Ganesha 10, Bandung 40132, Indonesia d) Center for Geological Disaster Research Jalan Sangkuriang, Bandung 40135, Indonesia Abstract The Sadakeling Karaha Volcano Complex is a type-C volcano in West Java Province. Based on the tectonics, this area can be a continuous fragment of the Australian Continent Argoland, which controls the magmatism process. This study aims to map this complex with volcanostratigraphy, the history of the formation and evolution of magma, and determine the tectonic setting and continuity of Argoland using petrogenesis studies. The type of data for this study uses Landsat-8 imagery to help with volcanostratigraphy, as well as rock samples by analyzing texture, plagioclase microtexture, and their geochemical content. Based on the volcanostratigraphy analysis, the Sadakeling Karaha complex consists of 4 Khuluks and 12 Volcanic Gumuks formed during 7 phases with fairly complex magma evolution characteristics. Specifically, characterized by repeated differentiation, magma assimilation and primitive magma injection as reflected by fluctuations in anorthite content, texture in each lava unit, and Harker diagrams between major oxide compounds and silica. The evolution of magma can be reflected from the plagioclase microtexture, which includes the crystal fractionation process, the decompression process due to primitive magma, the self-mixing process due to convection, heating due to primitive magma mixing, cooling due to eruption, and decompression process during the eruption. The geochemical studies reveal that the tectonic aspect of the Sadakeling Karaha Complex is part of a volcanic arc influenced by subduction processes and crustal contamination so that it is included in the active continental margin with magma series is tholeiitic - alkaline calc. Moreover, the Sr and Nd content and their comparisons show that contamination from the southeastern Australian continental crust influences the magma source formation process. Keywords: Volkanostratigraphy, Petrogenesis, Sadakeling Karaha Complex, Magma Evolution, Argoland. Share Link | Plain Format | Corresponding Author (Azrie Ezziat Putera Muhammad)

115	Solid Earth Sciences	ABS-65
Probability eruption, lahar flow and ashfall modeling of Semeru, East Java Province: Reference for mitigation Idham Andri Kurniawan, Mirzam Abdurrachman, Qurrata^aini Aisyah, Salma Sakinah, Muhammad Bahrun Najjah, Asep Saepuloh, Eddy Ariyono Subroto, Very Susanto, Arif Susanto, I Gusti Bagus Eddy Sucipta, Nurcahyo Indro Basuki, Niniek Rina Herdianita, Andri Slamet Subandrio, Emmy Suparka, Muhammad Saung Penggalih, Uut Ihsan Firman Sauqi Nur Sabila, and Abdillah. Petrology, Volcanology and Geochemistry Research group, Geological Engineering Program Study, Faculty of Earth Sciences and Technology, Bandung of Institute Technology. Abstract Semeru is one of the tallest volcanoes in Java and one of Indonesia^s most active volcanoes. Semeru eruption is dominated by the strombolian, with the flow of pyroclastic or lahar and ashfall being the primary source of the hazard. The aim of this study is to identify the potential hazards of the Semeru eruption. Based on eruption history data, this study used the probability of eruption with the event tree method, lahar flow modeling using LaharZ, and tephra fall modeling using TephraProb to evaluate the hazard. On the probability of eruption, this study used parameters such as restlessness, genesis, outcome, magnitude, phenomena, column eruption, sector, and distance. The source of secondary data is from the Global Volcanism Program website and the activity report of Semeru from The Center for Volcanology and Geological Hazard Mitigation (CVGHM) under the Geological Agency of the Indonesian Ministry of Energy and Mineral Resources. The eruption history data used focuses on eruptions from 2000 to 2022, a total of 24 eruptions. The geological conditions, magnitude and column eruption, and affected area are the main factors that determine the probability of hazard. Lahar flow modeling using LaharZ was performed on ArcGIS 10.8 with the input of Digital Elevation Model (DEM) data from DEM Nasional (DEMNAS). Lahar flow modeling focused on the December 4th, 2021 event. The results of this modeling are flow routes, volume of material, velocities, and travel times of lahar that can be used for rapid hazard assessment. The tephra fall modeling using TephraProb was performed on MATLAB with the input wind from NOAA, and thickness and other parameters from field observation. The ashfall modeling focused on the December 5th, 2020 event. The results of this modeling are isomass / isopach map and the value of hazard probability. Furthermore, this study can provide information to the government and the public regarding eruption products as a reference in mitigation activities. Keywords: Event tree, Lahar, LaharZ, ashfall, TephraProb, Mitigation, Semeru Share Link | Plain Format | Corresponding Author (Idham Andri Kurniawan)

116	Solid Earth Sciences	ABS-70
Orthometric Height Determination on Bali Island using the Geopotential Number Approach Dina Anggreni Sarsito (a*), Brian Bramanto (a), Dhota Pradipta (a), Heri Andreas (a) and Sidik Triwibowo (b) (a) Geodesy Research Group - Institut Teknologi Bandung, Labtek IXC 4th flr Ganesa 10 Bandung 40132, Indonesia *dina.sarsito[at]gmail.com (b) Indonesian Geospatial Information Agency, Jakarta - Bogor KM. 46, Kabupaten Bogor 16911, Indonesia Abstract Orthometric height is a type of physical height used by Indonesia in national or local reference systems for positioning that is used in various scientific and engineering activities. The main obstacle in determining the orthometric height is theoretically having to measure gravity measurement along the plumb line connecting the topography equipotential surface to the geoid surface where practically very difficult to realize. Another constraint is that it requires precise leveling measurements from the main point which is usually located on the coast to land far from the coast. This paper studies the possibility of estimating orthometric height values at several GNSS GPS stations in Bali using the geopotential number approach. The results obtained indicate the possibility of orthometric height determination in the Bali region without direct gravity measurements and precise leveling measurements. Keywords: Orthometric- Geopotential Number- Geoid- Gravity- Bali Share Link | Plain Format | Corresponding Author (dina anggreni sarsito)

117	Solid Earth Sciences	ABS-71
Petrogenesis Of Bawean Island In Lake Kastoba Area And Surrounding, Bawean Island, East Java: A Preliminary Study Based On Geochemical Data Muhammad Hafizh (a), Mirzam Abdurrachman (a), Muhammad Bahrun Najah (a) (a) Geological Engineering, Bandung Institute of Technology Jalan Ganesha 10, Bandung 40132, Indonesia Abstract Bawean Island is one of the islands with volcanoes in the Java Sea, north of Java Island. It is known that the rocks there has a high alkaline content. If seen from the position of Bawean Island, it is estimated that Bawean Island is still related to the subduction between the Indo-Australian Plate and the Eurasian Plate which occurs in the south of Java Island. To ensure the tectonic setting on Bawean Island, a petrogenesis approach is used using rock geochemical data. Geochemical data were obtained through analysis using XRF (for principal components) and ICP-MS (for trace components). The content of chemical compounds and discriminant diagrams are used to determine the tectonic order with parameters in the form of main components and trace components. Based on the plot results of the discriminant diagram of trace components in the form of TiO2/10-P2O5-MnO, Ti-Zr, and TiO2 content <1.3%, Bawean Island is included in the tectonic setting of a calc-alkaline island arc. Keywords: Geochemical- Petrogenesis- Bawean Island- High potassium Share Link | Plain Format | Corresponding Author (Muhammad Hafizh)

118	Solid Earth Sciences	ABS-77
PULL-APART GRABENS GEOMETRY ALONG THE SUMATRAN FAULT Dumex Pasaribu (1,2*), Benyamin Sapiie (1) and Indra Gunawan (1) 1) Institut Teknologi Bandung (ITB) Jalan Ganesha 10, Bandung 40132, Indonesia dumex.pasaribu[at]gmail.com 2) Universitas Pertamina (UPer) Jalan Teuku Nyak Arief Simprug, Jakarta Selatan 12220, Indonesia Abstract This study conducted to determine the geometry of pull-apart grabens along the Sumatran Fault. As known that Sumatran Fault is a dextral strike-slip fault formed as a strain partitioning in parallel vector partition from oblique convergence on the subduction zone of the southwest edge of Sundaland. This fault forms a wrench system which at the bottom has a deep-seated sub-vertical fault plane to the old crystalline basement, while the shallower parts to the surface in some places form the flower structures. The negative flower structures along the Sumatran Fault produce pull-apart grabens and potentially acting as sedimentation basin that can be seen nowadays in Sumatran Fault zone. The methodology in this study start with digital surface geological mapping on the Sumatran Fault wrench system using digital elevation model (DEM), bathymetry data, surface geological maps, combined with the seismicity maps, and data from the previous publications. The results of this digital surface mapping are determination of the pull-apart graben, calculation of the correlation of length to width of each graben. At least about 53 present day pull-apart grabens found, where there was one graben which was outlier and deformed due to volcanism. The approach in determining the pull-apart graben is calculating in two dimensions using the ellipsoid formation, so that the length is the elongated axis and the width is another axis in the middle that perpendicular to the length. The calculation of the correlation of length (x) to width (y) shows a linear relationship, y = 0.2563x with R2 = 0.8389, generally means the length of the graben in the Sumatra Fault zone is four times its width. Keywords: Sumatran Fault, wrench, pull-apart graben, ellipsoid formation Share Link | Plain Format | Corresponding Author (Dumex Pasaribu)

119	Solid Earth Sciences	ABS-82
Geochemical characteristics of Quaternary volcanic rocks from Guntur Volcano, West Java, Indonesia A A Kausar (a*), I Setiawan (a), Y M Lai (b), L Lintjewas (a,b) a. Research Centre for Geological Resources, National Research and Innovation Agency LIPI Bandung Area (BRIN Bandung-Cisitu), Sangkuriang St, Coblong, Bandung City, West Java 40135 *andrie.kausar[at]gmail.com b. Department of Earth Sciences, National Taiwan Normal University, Taipei, Taiwan 162, Section 1, Heping E. Rd., Taipei City 106, Taiwan Abstract Garut is one of the places that has geothermal prospects in West Java that has different geochemical characteristics from other volcanoes which makes it interesting to study. The research area is located on the southeast side of the Garut-Bandung Ancient Caldera which is regionally included in the Quaternary Volcanic Zone. This zone lies between the first magmatic belt located along the southern part of Java and is related to the Paleogene subduction and the second magmatic belt is located in the north of the first magmatic belt that is related to Neogene subduction. A total of 5 samples were taken volcanic rock samples were collected from Guntur volcanoes, whole-rock geochemistry provides two different trends from two different sampling localities which considered medium calc-alkaline to high-K calc-alkaline basalt and andesite, on the other side there are significant variations between their Rare Earth Elements (REE) patterns there. There is a possibility that the location of the Guntur volcano where formed is at the boundary between the Volcanic Front and Rear Arc, both magmas can erupt here, so it can see two different compositions. The objective of this research is to understand the geochemical characteristics of volcanic rocks and their tectonic environment. Keywords: Geochemical characteristics, volcanic rocks, quaternary volcanoes zone, tectonic environment Share Link | Plain Format | Corresponding Author (Andrie Al Kausar)

120	Solid Earth Sciences	ABS-83
THE RELATIONSHIP OF GEOLOGICAL CONDITIONS BETWEEN THE NGARAI SIANOK - MANINJAU GEOPARK AND THE SILOKEK GEOPARK Fachri Vanrenov (a*), Mirzam Abdurrachman (a), Idham Andri Kurniawan (a), Abdillah Baraas (a), Firman Sauqi Nur Sabila (a), Dian Hardiansyah (a), Fakhri Irsyad Anwar (a), Muhammad Bahrun Najah (a), Muhammad Hafizh (a) Faculty of Earth Sciences and Technology, Bandung Institute of Technology Jalan Ganesha 10, Bandung 40132, Indonesia *fachrivanrenov96[at]gmail.com Abstract Ngarai Sianok - Maninjau Geopark and Silokek Geopark are one of the national geoparks in West Sumatra Province, as it is known that this Sumatran fault extends from the Bay in Lampung to the northern part of Aceh, is a dextral slip fault and has undergone a 25-30 km. Formed as a result of the subduction of the Indo-Australian Plate which moves relative to the North under the Eurasian Plate, thus forming an oblique mechanism. One of the relationships between the Great Sumatran Fault is by looking at evidence from the geosites in the Sianok - Maninjau Geopark and the Silokek Geopark. What is visible is the formation of the Ngarai Sianok (Sianok Valley), which is the influence of a shear fault and creates a pull-apart basin negative flower structure, this section is part of the Sianok segment. Apart from the formation process, there is also the presence of a geosite which is quite interesting from the main presence in the form of the Sianok Gorge with turbidite deposits from the destruction of Mount Sitinjau which now creates a caldera that contains a meteoric water lake which is now called Lake Maninjau. Until it is old and is part of the basement in the Silokek Geopark area which looks like old granite. As a related link for the geotourism activities of these two geoparks with the petrographic, rock geochemical, and geomorphological methods which are very fascinating from the history of geology which explains the processes that occurred from the oldest perm age in the Silokek Geopark section, to the youngest process which is in the Sianok Geopark section. Keywords: Ngarai Sianok, Maninjau, Silokek, Geopark, Great Sumatran Fault, UNESCO Share Link | Plain Format | Corresponding Author (Muhammad Bahrun Najah)

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