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121	EARTH, ATMOSPHERIC, AND SPACE SCIENCE	ABS-104
Accuracy of Solar Azimuth Calculation with Aproximate Solar Coordinate (ASC) Algorithm as a Reference for Determining Qibla Direction M. Ihtirozun Niam (a), Ahmad Syifaul Anam (a) a) Universitas Islam Negeri Walisongo Semarang Jalan Prof. Hamka (Kampus III), Ngaliyan, Kota Semarang 50185, Indonesia *ihtirozun_n[at]walisongo.ac.id Abstract The reference that is often used in determining Qibla direction is the Azimuth of the Sun. Apart from being bright and large in size, the Sun quantitively is seen more often than any other celestial body. It is just that to get accurate solar data requires a fairly long calculation algorithm with corrections for more than 2000 step like the one in the Variations Seculaires des Orbites Planetaires (VSOP 87) algorithm. This article offers a relatively short algorithm with a correction less than 10 step but obtains accurate Solar azimuth results. The author uses an exploratory method with a comparative approach where the author explores the azimuth value of the Sun both before culmination and after culmination, seen from places in the southern and northern latitudes and at the solstice and equinox times, then compared with the Sun data calculated by VSOP 87 algorithm. The result is the difference azimuth value of the Sun between the ASC algorithm compared to VSOP 87 lest than1 arc minute, so it is still relatively accurate to use in calculating solar data as a reference for determining the Qibla direction. Keywords: Solar Azimuth- Aproximate Solar Coordinate (ASC) Algorithm- Qibla Direction Share Link | Plain Format | Corresponding Author (M. Ihtirozun Niam)

122	EARTH, ATMOSPHERIC, AND SPACE SCIENCE	ABS-106
Identification of Subsurface Structure Derived from Gravity Data in the Mud Volcano Area of Sangiran, Central Java, Indonesia Cahyo Aji Hapsoro(a*), Mariyanto(b), Eleonora Agustine(c), Mimin Iryanti(d), Rina Dwi Indriana(e), Mochamad Khoirul Rifai(a)(f), and Alpan Ibrahim(a) (a) Department of Physics, Faculty of Mathematics and Natural Science, Universitas Negeri Malang, Malang, 65416, Indonesia. (b) Department of Geophysical Engineering, Faculty of Civil, Planning and Geo Engineering, Institut Teknologi Sepuluh Nopember, Surabaya, 60111, Indonesia. (c) Department of Geophysics, Faculty of Mathematics and Natural Science, Universitas Padjadjaran, Bandung, 45363, Indonesia. (d) Department of Physics, Faculty of Education of Mathematics and Natural Science, Universitas Pendidikan Indonesia, Bandung, 40154, Indonesia. (e) Department of Physics, Faculty of Science and Mathematics, Universitas Diponegoro, Semarang, 50275, Indonesia. (f) Junior High School of Darul Faqih Indonesia, Malang, 65158, Indonesia. *Corresponding Author: cahyo.ajihapsoro.fmipa[at]um.ac.id Abstract Java Island, Indonesia, contains a variety of mud volcanoes. They are mainly located along the northern line of the island of Java. Each mud volcano has its characteristics and uniqueness. However, research on various mud volcanoes in Java Island still needs to be completed. This study uses gravity data to identify the surface structure of one of the mud volcanoes in the Sangiran area, Central Java. The study area measures 400 x 400 meters. Measurement of gravity method data with 81 points spaces 50 meters to determine the value of rock density and subsurface structure of Sangiran mud volcano area. Based on the data obtained, data processing is carried out to obtain a map of the distribution of regional and residual gravity anomaly values. 3D inversion was used to create a subsurface structural map from the anomaly data. The 3D gravity inversion modeling results indicate that a high-density rock block is interpreted as a basin containing the mud volcanos reservoir. The presence of mud content contributes to the distribution of low density on the surface and around the mudflow of the Sangiran mud volcano. A fault zone could exist in the west-to-east direction from the research region. Keywords: Sangiran- Mud volcano- Subsurface structure- Inversion- Gravity method Share Link | Plain Format | Corresponding Author (Mochamad Khoirul Rifai)

123	EARTH, ATMOSPHERIC, AND SPACE SCIENCE	ABS-364
Self-Combustion Potential Analysis Based on Proximate Data on PT. Geoservices Samarinda Wahidah (a*), Delia Aurora Fajarwati (b), Piter Lepong (a), Andi Alamsyah (a) (a) Geophysics Department, Faculty of Mathemathics and Natural Sciences, Mulawarman University (b) Physics Department, Faculty of Mathemathics and Natural Sciences, Mulawarman University *wahidah[at]fmipa.unmul.ac.id Abstract The self-combustion phenomenon that has the potential to cause fires in the coal mining industry in East Kalimantan is the subject of this study. The purpose of this study is to determine the quality and characteristics of coal that has the potential to trigger self-heating. In this research, 5 (five) samples of coal quality are analyzed from PT. Geoservice Samarinda using the proximate analysis method and analysis of calorific value and total sulfur. Next, determine ranking of coal and analyze the characteristics of coal samples that are prone to potential self-combustion. The results show that the five coal samples included in Sub-Bituminous rank with medium volatile matter considered to have sufficient potential to experience self-combustion. The most susceptible coal sample is sample code D1 because it also has lower inherent moisture and ash content and higher total sulfur content than other coal samples. However, further tests still need to be carried out to determine the percentage of total sulfur (pyrite) as a trigger for self-combustion. Environmental factor analysis is also required for validation. Keywords: Coal, quality, self-combustion, proximate Share Link | Plain Format | Corresponding Author (Wahidah Wahidah)

124	EARTH, ATMOSPHERIC, AND SPACE SCIENCE	ABS-109
Multi-technical Analysis For Reservoir Rock Characterization Using Micro-CT, SEM-EDX and XRD Fahrisah Nurfadeliah Bahraini (a*), Fourier Dzar Eljabbar Latief (a) a) Physics of Earth and Complex Systems, Faculty of Mathematics and Natural Sciences Bandung Institute of Technology, Jalan Ganesha 10, Bandung 40132, Indonesia *fahrisahnurfa2[at]gmail.com Abstract Enhanced Oil Recovery (EOR) is a technique that can be used to optimize the process of extracting oil in porous rocks. This technique requires information about the characteristics of hydrocarbon reservoir rocks in oil wells to be more effective. Therefore, research related to the characteristics of hydrocarbon reservoir rocks using several methods can be carried out, i.e., using Micro Computed Tomography (Micro-CT), X-Ray Diffraction (XRD), and Scanning Electron Microscope-Energy Dispersive X-Ray (SEM-EDX). This study aims to analyze and relate several characterization methods that impact optimizing oil extraction. Micro-CT can be used to obtain projected images of reservoir rock samples which can be processed using Digital Rock Physics (DRP) analysis. Porosity and permeability values can be obtained using these tests. XRD is used to obtain information related to the mineralogy of the sample by calculating the diffraction angle. SEM-EDX can show the morphology of the clay mineral structure and the types of elements on the sample^s surface. These three tests provide results that can mutually improve the analysis of the samples studied. This analysis showed that the sample has a porosity of >20%. The sample is mainly composed of quartz grains with the surrounding dickite clay minerals, and the detected elements are C, O, Al, Si, and K. The permeability obtained was greatly influenced by the complexity detected in the sample. With the procedure that has been developed, this multi-technique analysis is expected to complement the direct (physical-based) measurement technique. Keywords: clay minerals- Micro-CT- permeability- porosity- SEM- XRD- X-rays Share Link | Plain Format | Corresponding Author (Fahrisah Nurfadeliah Bahraini)

125	EARTH, ATMOSPHERIC, AND SPACE SCIENCE	ABS-365
Petroleum Prospectivity Analysis of Acreage Blocks W13-19 & W13-20 in the offshore North Perth Basin: Overburden Aspect Andi Alamsyah (1) (2), Mark Bunch (2), Wahidah (1) 1. Geophysics Department, Universitas Mulawarman 2. Australian School of Petroleum, University of Adelaide Abstract Overburden rock is the sum of all layers above the source rock, reservoir rock and seal. It is one of an essential element in petroleum system due to it affecting the performance of every other element and process of the petroleum system. In this study, the combination of literature, well completion reports and the generation of a map and analysis charts have been used to investigate the performance of overburden rock in assessing the petroleum Prospectivity Analysis of Acreage Blocks W13-19 & W13-20 in the offshore North Perth Basin. At first, a thickness map of overburden was generated from seismic data to see its distribution in the acreage W13-19 and W13-20. A porosity chart over time was analyzed to see how overburden rock affects these properties, particularly in the reservoirs (Dongara Sequences and Cattamarra Coal Measures Sequences) and the regional seal (Kockatea Shale and Cadda Sequences). Eventually, a vitrinite reflectance over time plot was analyzed to understand the relationship between the thickness of overburden and maturity level of the source rock as well as the effect on the time of generation. From this investigation, we understood that both central and southern Houtman Sub-basin have a relatively same quantity of overburden accumulation and sufficient enough to hydrocarbon to be generated from potential source rock while Wittecarra Terrace that is part of Abrolhos Sub-basin has smaller accommodation space due its position in footwall block which is higher than Houtman Sub-basin. As consequence, it accumulates a thinner amount of sediment. On the other hand, having known that there are three subsidences that influence the thickness of overburden and sedimentation rate, the most influencial subsidence is in early Permian to early Jurassic. Keywords: Overburden rock, petroleum prospectivity, northern perth basin Share Link | Plain Format | Corresponding Author (Andi Alamsyah)

126	EARTH, ATMOSPHERIC, AND SPACE SCIENCE	ABS-113
Volcanostratigraphy of Cimaung Valley: Application and Combination of Landsat Imagery and Field Observations of Cimaung Sub-District, Bandung District, West Java Billy Petrus Wehelmus (a*), Rifo Rausyan Fikri (a), Elvis Okvianta (a), Taufik Ismail (b,c), Riyan Hidyatulloh (a), Muhammad Agung Gumilar (a), Dwigko Kurniawan Wandray (a), Mirzam Abdurrachman (b) a) Department of Geology, Indonesia College of Mineral and Technology, Bandung 40263, Indonesia billysaa0612[at]gmail.com b) Faculty of Earth Sciences and Technology, Bandung Institute of Technology, Bandung 40132, Indonesia c) Center of Geological Disaster Research, Indonesia Agency of Research and Innovation, Bandung 40135, Indonesia Abstract The research area is composed of rocks from the activities of three volcanoes, namely Mount Tanjaknangsi in the west, Mount Malabar in the east and Mount Tilu in the south which is located in Bandung Regency, West Java Province. This study aims to determine the surface geology mapped at a scale of 1:12,500 and to determine the volcanostratigraphy and geological history that make up the study area. Vulcanostratigraphy is made by integrating literature studies, direct field observations of rock outcrops, and petrographic analysis and analysis of satellite images in the form of topographic maps and satellite images, namely DEM (Digital Elevation Model) and ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer). Results of the observations and analysis are poured into outcrop observation point maps, volcanostratigraphic profile maps, geological maps, cross-sectional geology and geological history blocks. Volcanostratigraphy of the study area is divided into 3 khuluk and 8 volcanic dunes and 24 rock units consisting of 18 lava units, 5 pyroclastic units and 1 lahar unit. There are at least 3 phases of volcanic formation in the geological history of the study area. The geological structure that develops in the study area is in the form of a primary structure, namely a joint with sheets showing an activity of lava flow and a secondary structure in the form of a volcanic crater structure which shows the remains of the eruption center of a volcano. Keywords: Vulcanostratigraphy- Landsat Imagery- Bandung Share Link | Plain Format | Corresponding Author (Billy Petrus Wehelmus saa)

127	EARTH, ATMOSPHERIC, AND SPACE SCIENCE	ABS-373
Variability of Sea Wave Height during ENSO Periods in the Makassar Strait Sevti Viqa Haiyqal (a,d*), Aris Ismanto (b,c), Elis Indrayanti (b), Randy Andrianto (d) (a) Faculty of Fisheries and Marine Sciences, Diponegoro University *viqahaiyqal[at]gmail.com (b) Departement of 0ceanoghraphy, Faculty of Fisheries and Marine Sciences, Diponegoro University (c) Centre for Coastal Rehabilitation and Disaster Mitigation Studies, Diponegoro University Jl. Prof. H. Sudarto, SH, Tembalang Semarang, Jawa Tengah 50275 Indonesia (d) Meteorological, Climatological, dan Geophysical Agency Jl. Angkasa I, No. 2 Kemayoran, Jakarta Pusat 10610, Indonesia Abstract Sea surface temperature anomalies in the tropical Pacific Ocean affect climate variability which causes changes in atmospheric dynamics and oceanography. One of the physical parameters of oceanography that is affected is wind and waves. Waves generated by the wind (wind waves) have a significant influence on various human activities in the sea such as transportation, offshore drilling, tourism, fishing, development of coastal infrastructure and utilization of energy resources. The Makassar Strait is a strategic water that includes all of these activities. In the context of efficiency and safety, it is necessary to have accurate wave height information covering various conditions. This study aims to determine the variability of wave height which is influenced by climate variability in the form of ENSO in the Makassar Strait. Therefore, the pattern of wave height can be known in the Normal, El Nino, and La Nina phases by using wind and wave data for the 2013-2022 period from Hindcasts-OFS BMKG. As a result, validation of the BMKG-OFS wave data against observation data using a wave recorder showed an RMSE value of 0.27 - 0.36. The ENSO phenomenon (El Nino/La Nina) greatly influences the increase in sea wave height from normal during the Asian Monsoon period (December, January, February) and during the Australian monsoon period (June, July, August). The increase in wave height during the El Nino phenomenon occurs during the Australian monsoon period (JJA) while during the La Nina phenomenon the increase in wave height occurs during the Asian Monsoon period (DJF). The La Nina phenomenon greatly influences wave height in the southern part of the Makassar Strait during both the Asian and Australian monsoons. Keywords: variability, monsoon, Hindcast OFS BMKG Share Link | Plain Format | Corresponding Author (Sevti Viqa Haiyqal)

128	EARTH, ATMOSPHERIC, AND SPACE SCIENCE	ABS-119
Proper Motion of Individual Sunspot and Photospheric Magnetic Properties Related to X-class Flare in NOAA AR12158 Dhani Herdiwijaya, Arifa Eva Celinia Candra, Chandra Alif Fernanda, Miftahul Husna Astronomy Division, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Ganesha 10 Bandung, Indonesia 40132 Abstract Sunspots and their dynamics dominate the magnetic topology and evolution of both the photosphere and the overlying coronal active regions. Thus, a comprehensive understanding of their behaviour is essential to understanding the solar magnetic field represented by white-light images and magnetogram data. Based on high resolution images obtained from Helioseismic and Magnetic Imager (HMI) instrument onboard Solar Dynamic Observatory (SDO) satellite at visual wavelength, we traced individual umbral sunspots to find drift motion during flare occurrences within NOAA Active Region (AR) 12158 (N11E05) from September 7 to 11, 2014. We measured relative motion of 111 sunspots in 151 frames. The sunspot group was characterized by about 440 millionth solar hemisphere in the area and complex magnetic morphology with beta-gamma-delta class. Photospheric magnetic properties through SHARP parameters, based on SDO/HMI continuum and magnetogram were computed. We found a strong relation of rotation motion and variability of magnetic characteristics before and post-flare. Some sunspots showed faster motion and moved slowly nearly along the magnetic field polarity inversion line that showed shear motion. Large-scale twisting or helicity of sunspot magnetic flux tubes posed implications with the build-up of instabilities that may lead to eruptions. Flare outburst which is occurred in corona layer affected sunspot motion and area, as seen for their changing configuration and morphology, before and after peaked X-ray intensity. This result indicates that there is a strong connection between X-ray solar flare at corona layer and its foot points motion at photosphere. Keywords: Sun: activity, flares, photosphere, magnetic fields, sunspots Share Link | Plain Format | Corresponding Author (Dhani Herdiwijaya)

129	EARTH, ATMOSPHERIC, AND SPACE SCIENCE	ABS-376
Development of Numerical Simulations in Determining The Energy Liberated From A Magma Chamber Alamta Singarimbun Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Ganesha 10, Bandung, 40132, Indonesia Abstract In the sequence processing of cooling magma, heat is lost to its surroundings. In this process, liquid fractionation of molten magma may occur. Gas bubbles rise and grow in the magma. Under the action of buoyancy effect, the gas bubbles go to the roof of the magma chamber and then they go to the earth^s surface through the fracture zone area. It suggests us that these features reflect the dynamics of the degassing magma. The flow rate of the discharge magmatic water depends on the temperature (T), viscosity of magma (&#956-), density of gas (&#961-_g), density of molten magma (&#961-_m), the gas volume fraction in the magma (&#945-), dan gravity acceleration (g). By using a model of degassing magma with some assumptions, the flow rate of magmatic water discharged can be estimated. Keywords: magma, viscosity, density, magma fraction volume, gravity acceleration Share Link | Plain Format | Corresponding Author (Alamta Singarimbun)

130	EARTH, ATMOSPHERIC, AND SPACE SCIENCE	ABS-377
Contribution of Physics in the Development of Geothermal Energy as a Renewable Energy Alamta Singarimbun Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Ganesha 10, Bandung, 40132, Indonesia Abstract Indonesia is very fortunate because it has many volcanic areas. Volcanic areas have the potential to store geothermal energy. Geothermal reservoirs are a renewable energy source. Geothermal energy is extracted from the heat energy of magma beneath the earth^s surface through the water. Besides being renewable, geothermal energy is also environmentally friendly. Several countries have succeeded in using geothermal energy as an energy source, especially for electricity generation. Indonesia has also taken advantage of it, although still in a small order. In the future, geothermal energy needs serious attention to be developed as a response to the challenges of the world^s need for energy, especially in Indonesia. Various sciences (multidisciplinary), especially physics, are needed to utilise geothermal energy, starting from exploration, exploitation, and economic aspects. The initial problem that arises is the problem of exploration. Namely determining whether or not there is and where the geothermal reservoir is located. The search and estimation of geothermal reservoir reserves need to be known properly. Although it is not known for certain, according to allegations, Indonesia has the largest geothermal resources in the world. There are no quantitative numbers to express it because this depends on the type and quality of research conducted processes in geothermal are physical processes. Therefore, the role of physics is very important in geothermal studies, including Thermodynamics, Fluid Flow, and Pysical Properties of Earth Materials which can be searched for by exploration geophysics research such as the CSAMT method, the TDEM method, the Gravity method, the Magnetic method, Self Potential method, and others. Keywords: geothermal, energy, reservoir, exploration, exploitation, thermodynamics, fluid flow, CSAMT method, Gravity method, Magnetic method, SP method Share Link | Plain Format | Corresponding Author (Alamta Singarimbun)

131	EARTH, ATMOSPHERIC, AND SPACE SCIENCE	ABS-122
The Uniqueness of Natural Background Radiation in Mamuju Regency: Environmental and Individual Radiation Dose Adi R.A. Abdullah (a), Sidik Permana (a,b,c,d), Wahyu Srigutomo (d), Alan Maulana (e), Haryo Seno (e), Ismail Humolungo (b),Zulfahmi (c) (a)Doctoral Program in Nuclear Engineering Department, Bandung Institute of Technology, Jl. Ganesha No. 10, Bandung, Indonesia. (b)Master Program in Nuclear Science and Engineering Department, Bandung Institute of Technology, Jl. Ganesha No. 10, Bandung, Indonesia. (c)Master Program in Physics of Teaching Department, Bandung Institute of Technology, Jl. Ganesha No. 10, Bandung, Indonesia (d)Physics Department, Bandung Institute of Technology, Jl. Ganesha No. 10, Bandung, Indonesia. (e)Indonesia^s National Research and Inovation Agency. Jl. Tamansari No. 71, Bandung, Indonesia. Abstract The natural radiation environment in an area containing radioactive mineral deposits will result in unique natural radiation levels. The higher content of radioactive elements, especially uranium and thorium, in soil and rocks causes high exposure to natural radiation. In this study, measurements of natural radiation levels were carried out in Mamuju Regency, West Sulawesi, as the area with the highest exposure to natural radiation in Indonesia, using Scintilator NaI(Tl) and Geiger Muller to measure environmental radiation levels and personal dosimeters to measure doses. radiation absorbed by each individual. Measurements with the NaI(Tl) scintillator produced an average value of the environmental radiation dose rate of 0.3351 &#956-Sv/hour and Geiger Muller of 0.770 &#956-Sv/hour. The average annual effective annual dose is 0.5348 mSv per year from the NaI(Tl) scintillator data and 1.3606 mSv per year from the Geiger Muller data, which is still in the very low level radiation category and does not give any health effects. Meanwhile, from a personal dosimeter that calculates how much radiation an individual can absorb, an average dose rate of 0.944 uSv/hour is obtained and the average annual effective dose that can be received by an individual is 6.8347 mSv. Higher than the global effective annual dose that individuals can receive from natural sources of 2.4 mSv Keywords: dose rate, annual dose effective, Nai(Tl) scintilator, geiger muller, personal dosimeters, Mamuju. Share Link | Plain Format | Corresponding Author (Adi Rahmansyah Amir Abdullah)

132	EARTH, ATMOSPHERIC, AND SPACE SCIENCE	ABS-137
Marine Resistivity Tomography for imaging the underwater sedimentation in North Java Sea Bagus Endar B. Nurhandoko (1,3), Syukri Fitrialdi(2), Kaswandhi Triyoso (3), Satryo Agung Wibowo(3), Insan Rizal Komara(3), Wisnu Guntara(3), Diah Asmawati(3), Gogot Panca Parijogo(2), Ratih Pratiwi(1), Maria Cindrawati(1), and Eko B. Supriyanto (3) 1) Physics Department of Institut Teknologi Bandung 2) Taka Hydro Core Indonesia 3) LPIK ITB- Abstract The North Java Sea coast suffers abrasion and siltation phenomena. This abrasion phenomenon has become intense in the last decades on the shore of the North Java Sea. Some authors said abrasion has occurred over the last 50 years, especially in the Eretan, Indramayu, and Cirebon districts. On the other hand, the coastal area of the North Java sea has crowded infrastructures, namely roads and oil-gas pipelines, and has highly populated areas. We acquired data from marine resistivity tomography to image submarine sedimentation around Eretan and Cirebon coasts. The marine resistivity tomography data acquisition is carried out to image the underwater offshore of the Eretan coast and the Cirebon coast. The underwater resistivity information can be used for corrosion protection and imaging of the sedimentation layer. The subsurface results from marine resistivity tomography can also map the hard and soft layer position distribution. Suppose the results of this imaging are correlated with wells or the Rock Physics analysis. They will be able to map the distribution of subsurface lithology. Therefore, in the future, these results can be used for studies on handling abrasion and designing underwater infrastructure. We use some configurations of measurements for marine resistivity tomography: static and dynamic measurement. The static measurement uses Wenner-Alpha configuration and Wenner-Schlumberger. The dynamic measurement, measured while moving the ship, uses the inverse of the Schlumberger measurement. The result shows the presence of a high resistivity layer in the subsurface of the seabed, which may be an as hard layer in the subsurface of the seabed of Eretan bay. Keywords: Underwater imaging, subsurface seabed imaging, marine resistivity tomography, sedimentation, underwater lithology imaging Share Link | Plain Format | Corresponding Author (Bagus Endar Nurhandoko)

133	EARTH, ATMOSPHERIC, AND SPACE SCIENCE	ABS-145
Analysis of Aftershock Decay Bali Earthquake 13 December 2022 using GEOSTAT Software Version 2.0 for Seismic Risk Reduction Takhul Bakhtiar BMKG Abstract There has been an earthquake in the Bali Region with a magnitude of M5.2 on December 13, 2022 with a depth of 10 km. This event resulted in a series of aftershocks. This event resulted in a series of aftershocks. This study aims to analyze the decay time of aftershocks that occurred in the area as a mitigation measure and reduce the risk of earthquakes. The method used in this research is the method of Mogi I, Mogi II, Omori and Utsu in GEOSTAT V2.0 software. This study uses the earthquake repository data BMKG for a period of 7 days since the Mainshock occurred. The calculation results show that aftershocks are predicted to decay on the 14th day for the Mogi I method (r = -0.96468), the 9 th day for Mogi II (r = -0.9577), the 14th day for Utsu (r = -0.96484) and 17th Day for Omori (r = 0.922). A suitable method for predicting the decay time of aftershocks is the Utsu method (r = -0.96484). Estimated time of aftershock decay can be used as an effort to mitigate and reduce the risk of earthquakes. Keywords: Omori, Mogi I, Mogi II, Utsu, Aftershock decay, Seismic Risk Reduction Share Link | Plain Format | Corresponding Author (Takhul Bakhtiar)

134	EARTH, ATMOSPHERIC, AND SPACE SCIENCE	ABS-157
OBSERVATIONS OF MIXED ROSSBY-GRAVITY (MRG) WAVES AS A MJO CONVECTIVE CLOUD INITIATION USING GNSS-RO DATA Herdiana Sri Wahyuningsih1, Nurjanna Joko Trilaksono2, Noersomadi3 1 Earth Science Program, Institut Teknologi Bandung, Indonesia 2 Atmospheric Science Research Group, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung, Indonesia 3 Research Center for Climate and Atmosphere, National Research and Innovation Agency (BRIN), Bandung, Indonesia Abstract The Madden Julian Oscillation (MJO) is the intra seasonally eastward propagation of convective activity initiated from the Indian Ocean then passing through the Maritime Continents and continued to the Pacific Ocean. The aim of this study is to determine the role of a weekly westward Mixed Rossby Gravity (MRG) waves in triggering MJO convective clouds by analyzing the vertical temperature fluctuations in the upper troposphere and lower stratosphere. We investigate temperature profile, which has a vertical resolution of 0.1 km, retrieved with the Constellation Observing System for Meteorology Ionosphere and Climate (COSMIC2) Global Navigation Satellite System Radio Occultation (GNSSRO). We applied space-time spectral analysis at 14 km (upper troposphere), 17 km (tropopause) and 21 km (lower stratosphere) to elucidate the wave interaction within the pre-, during and post-MJO phase. In the pre-MJO phase, the MRG initiates the thermal variations between the upper troposphere (warm anomaly) and tropopause (cold anomaly) form a likely dipole stratification due to the relaxation of latent heat released from the convective clouds. The height and longitude time cross section shows an eastward tilt with height wave propagation from the Indian Ocean to the Western Pacific. Keywords: MJO, MRG, COSMIC2-GNSSRO, Mid-troposphere Share Link | Plain Format | Corresponding Author (Herdiana Sri Wahyuningsih)

135	EARTH, ATMOSPHERIC, AND SPACE SCIENCE	ABS-158
Optical Spectroscopy and Photoionization Model of NGC 6572 Muhammad Fajrin (a), Hakim L. Malasan(a,b,c,d,*), Evan I. Akbar(a,b), Aliyya N. Rahma(a), Irfan Imaduddin(a), Agus T. P. Jatmiko (b) a) Department of Astronomy, Bandung Institute of Technology Jalan Ganesha 10, Bandung 40132, Indonesia b) Bosscha Observatory, Institut Teknologi Bandung Jalan Peneropongan Bintang, Bandung Barat 40391, Indonesia c) Atmospheric and Planetary Science Study Program, Institut Teknologi Sumatera, Lampung, Indonesia Jalan Terusan Ryacudu, Lampung Selatan 35365, Indonesia d) ITERA Astronomical Observatory, Sumatera Institute of Technology Jalan Terusan Ryacudu, Lampung Selatan 35365, Indonesia *Email: hakim[at]as.itb.ac.id Abstract We investigate the planetary nebula NGC 6572 through optical spectroscopy carried out at the Bosscha Observatory to determine its kinematical and chemical properties. Two intermediate dispersion spectra (R\(sim\)5000) centered around H\(alpha\) and H\(beta\) each obtained using Shelyak^s LHIRES III (1200 grooves/mm) spectrograph mounted on 10inch SCT Meade LX200R (F/9.84) are used to derive the nebular expansion velocity from emission lines associated with H\(alpha\), H\(beta\), [OIII], [NII], and [SII] ions. One low dispersion spectrum (R\(sim\)1000) obtained using 11inch SCT Celestron C11 (F/10) and NEO-R1000 (600 grooves/mm) long-slit spectrograph is used to determine nebular electron temperature, electron density, and its chemical composition. We also perform photoionization modelling to construct a self-consistent nebular model using Cloudy C17.02 to obtain reliable physical quantities. Spectral images of the intermediate resolution spectra successfully show the global elliptical structure of the nebula. The expansion velocity deduced from most of the emission lines agree with the published values which is around 15-20 Km/s. The deduced nebular physical properties also agree well with those determined by other works. Nebular abundances are substantially lower than that of solar, except for oxygen. Discrepancies are apparent when comparing line intensities of the observed data with the ones resulted from photoionization model. Further spectroscopic observations with higher resolution and with various position angle will be very useful to reveal more complete and detail structure of the nebula while spectra that covers wider wavelength range are recommended to better deduce the nebular physical properties. Keywords: Spectroscopy- Planetary nebula- Expansion velocity- Chemical abundance- Photoionization model Share Link | Plain Format | Corresponding Author (Muhammad Fajrin)

136	EARTH, ATMOSPHERIC, AND SPACE SCIENCE	ABS-160
Exoplanets With Earth Similarity Index (ESI) >= 0.8: Searching for Earth-like Exoplanets Using ESI With 2 Parameters Ferry M. Simatupang Institut Teknologi Bandung Abstract Currently, the number of confirmed exoplanets has reached more than five thousand exoplanets in nearly four thousand planetary systems. The existing data is not all complete, because exoplanets are detected by various methods, each of which provides certain different information. In this work, using the latest data compiled at exoplanet.eu, I try to find exoplanets that can be categorized as Earth-like exoplanets. The search for Earth-like exoplanets is carried out using the formulation of a similarity measure called the Earth Similarity Index (ESI). This ESI is a number between 0 and 1, where 0 denotes no similarity at all, and 1 is identical to Earth. The ESI formulation used is ESI with 2 parameters, namely the planet radius and host star flux received by the planet. Using ESI with 2 parameters, 15 exoplanets from 14 planetary systems were found. These exoplanets in their planetary systems are then compared with Earth in the Solar System. Keywords: exoplanet, ESI Share Link | Plain Format | Corresponding Author (Ferry M Simatupang)

137	EARTH, ATMOSPHERIC, AND SPACE SCIENCE	ABS-161
Multicriteria Assesment of Palm Oil Land Suitability Index in Southeast Asia Alief Wiraguna Aseran (a), Raka Putra Pratama (a), Anjar Dimara Sakti (a), Agung Budi Harto (a) a) Geodetic and Geomatics Engineering, Bandung Institute of Technology Jalan Ganesha 10, Bandung 40132, Indonesia Abstract Oil palm (Elaeis guineensis) has become the most important oil crop throughout the world. The growing palm oil production was mainly based on the expansion of cultivated area into forest areas, causing serious environmental. Increasing yields on existing plantations is a potential pathway to reduce the undesired ecological impacts of oil palm agriculture, It is estimated that global demand will continue to grow over time. With so many palm oil sectors, Southeast Asia is one of the most important factors in the world^s palm oil economy. Palm oil is known as the most efficient oil-producing crop globally. At the age of 25 years and over, old trees are cut down to start the cycle of replanting oil palm to maintain plantation productivity and economic viability. The distribution of land suitable for oil palm plantations is dominated by the upper middle class with a range of values of 24-28, where oil palm plantations that have the highest suitability value are in the Sandakan region of Malaysia, with a range of values of 28-37. while the lowest is located in the southern part of North Sumatra which is dominated by a value <24. based on the result the area of each class of suitability of oil palm land is the Lowest 2%, Low 10%, Mid 38%, High 33%, and Highest 17% of the entire study area. Keywords: Oil Palm, Suitability, Multi-Criteria, Climate Share Link | Plain Format | Corresponding Author (Alief Wiraguna Aseran)

138	EARTH, ATMOSPHERIC, AND SPACE SCIENCE	ABS-175
Analysis of Solar Wind Parameters Related to Geomagnetic Storms Using Detrended Fluctuation Analysis (DFA) Method Miftahul Husna, Dhani Herdiwijaya, and Chandra Alif Fernanda Astronomy Division, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Ganesha 10 Bandung, Indonesia 40132 Email: dhani.herdiwijaya[at]itb.ac.id Abstract The propagation of the Solar Wind (SW) by carrying plasma and magnetic fields that reach the Earth and potential to cause impacts on the Earth^s environment. SW triggers the occurrence of disturbances in the Earth^s magnetic field on a global scale known as geomagnetic storms. We present a study of the nature and general patterns of fluctuations in the SW^s parameters as a function of time. We choose samples of strong class geomagnetic storm (SGS) events for the Sun^s 20th to 21st cycles (October 1964 - September 1986). Within that range, there are 120 strong to extreme-class geomagnetic storm events. We analyzed the parameters of the SW^s fluctuating using the Detrended Fluctuation Analysis (DFA) method resulting in an alpha component (Hurst exponent generalized). The range of alpha values on the SGS event sample for six days before the peak of 0.02<alpha<5.62 (dominated by persistent processes), on the peak day of 0<alpha<5.6 (dominated by nonstationary processes), and six days after the peak of 0<alpha<3.23 (dominated by persistent processes). Parameters with persistent process types are relatively easier to use as one of the tools that can be used in prediction. Unlike the peak of a storm, the process is predominantly nonstationary which changes with time, difficult to use in predictions. However, a longer data range is needed to see a complete pattern in SW parameters because geomagnetic storms are complex systems that are difficult to predict. Therefore, an examination is required on the next cycle of the Sun. Keywords: Solar wind, Strong Geomagnetic Storm (SGS), Detrended Fluctuation Analysis (DFA), Hurst exponent, process: persistent- anti-persistent- nonstationary- and stationary Share Link | Plain Format | Corresponding Author (Miftahul Husna)

139	EARTH, ATMOSPHERIC, AND SPACE SCIENCE	ABS-180
Climate variability analysis of rice productivity in the central Kalimantan Indonesia M. Farid Suryadi, Joko Wiratmo Faculty of Earth Science and Technology Bandung Institute of Technology Abstract The study aims to know how climate variability affects the condition of rainfall and rice productivity. The climate variability reckoned in the study are El Nino and Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD). Pulang Pisau district in the central Kalimantan is chosen as a research area because it is a new national food estate area off the island of Java. The data used on the study is the temperature reanalysis data of ERA5-land, GPCC precipitation data, the climate index data of ONI and DMI, and data of rice productivity. The path analysis method, which is an extension of the linear regression, is used to see the chain of influence between variables. Path analysis shows that ENSO and IOD have a 15.3% impact on rainfall. ENSO has an impact of -0.09 while the IOD affects -0.04. For a combination of ENSO, IOD, and rainfall variables have an impact on 37.3% of rice productivity. ENSO has a greater direct influence on rice productivity of 0.06 compared with IOD 0.014. Keywords: ENSO, food estate, IOD, path analysis, rice productivity Share Link | Plain Format | Corresponding Author (Joko Wiratmo)

140	EARTH, ATMOSPHERIC, AND SPACE SCIENCE	ABS-193
Exploratory CCD photometric observations at Tillong Science Center, National Astronomical Observatory Hakim L. Malasan(1,3), E. Sungging Mumpuni(2), Abdul Rachman(2), Andreas C. Louk (4), J.A. Utama (5),, Rizky Kurniawan (3), Ghaida Suroya (5), Furtuosa D.F. Amaral(4) (1) Institut Teknologi Bandung (2) ORPA National Research and Innovation Agency (3) Sumatra Institute of Technology (4) The University of Nusa Cendana (5) Indonesia University of Education Abstract We have made CCD absolute photometric observations at Tilong Science Center, Kupang, NTT in two nights on September 2022. The telescope used was a 25 cm (F/10.0) Takahashi Mewlon-250CRS Reflector, equipped with an SBIG STF 8300M CCD camera and set of BVR Bessel Filters. In general the sky was partially clear, with a photometric night on 26 September 2022. The aims are to deduce atmospheric extinction coefficients, colour coefficients, zero point photometric system, and sky brightness above Tilong. Besides 8 fields stars (Landolt, 1992), we also observered standard photometric open cluster, IC 4665. In general the obtained data is good in term of its quality. Results of the observations will be presented, and discussions on the deduced parameters will be given. Recommendation for a regular based absolute photometric observations in Tilong Science Center as well as at Timau Observatory will be outlined. Keywords: Astronomical photometry, CCD, Observatory Share Link | Plain Format | Corresponding Author (Hakim Luthfi Malasan)

141	EARTH, ATMOSPHERIC, AND SPACE SCIENCE	ABS-199
Color Index Method for New Alternative Determining Fajr Time Hendro Setyanto (a*), Hendra Agus Prastyo (b) a) Imahnoong Observatory and Planetarium, Lembang, Indonesia *setyanto[at]gmail.com b) Department of Atmospheric and Planetary Sciences, Sumatera Institute of Tecnology, Jalan Terusan Ryacudu, Lampung Selatan 35365, Indonesia Abstract Astronomers use the color index method to determine a star^s temperature by subtracting its magnitude in different filters. A lower value of the star^s color index means the temperature is hotter than the higher value of a color index. This method helps astronomers classify stars^ temperatures in the universe. Inspired by this method, we use it as a new alternative to determining fajr time from imagery data to find the reddening effect of the sky. The images of fajr were taken by using a DLSR camera and then split into three bands, called R (Red), G (Green), and B (Blue). These images of fajr were taken at National Observatory in Timau-NTT. The color index method is used to find the value R-G and R-B for each image. To see when the reddening effect of the eastern sky begins, the value of the R-G color index compares to the value of the R-B color index. The results show that when the Sun^s altitude is -48 degrees, the value of R-G is 0.40 while the value of R-B is -0.99. The reddening impact on the eastern sky begins when the Sun^s altitude is -20 degrees. Keywords: Color Index- Fajr- Reddening Effect Share Link | Plain Format | Corresponding Author (Hendra Agus Prastyo)

142	EARTH, ATMOSPHERIC, AND SPACE SCIENCE	ABS-203
The Correlation and Weight of Topography Also Rainfall Factors using Principal Component Analysis in Flood Analysis Nanda Khoirunisa (a*,b), Nurul Asyikin (a), Qori Fajar Hermawan (a,c), Zetsaona Sihotang (a,b), and Muhammad Riza (a,b) a) Geophysics Study Program, Faculty of Mathematics and Natural Sciences, Mulawarman University Jalan Barong Tongkok, Samarinda City, East Kalimantan 75242, Indonesia *nandakhoirunisa[at]fmipa.unmul.ac.id b) Oceanography Laboratory, Faculty of Mathematics and Natural Sciences, Mulawarman University Jalan Barong Tongkok, Samarinda City, East Kalimantan 75242, Indonesia c) Geophysics Laboratory, Faculty of Mathematics and Natural Sciences, Mulawarman University Jalan Barong Tongkok, Samarinda City, East Kalimantan 75242, Indonesia Abstract The earth is vulnerable from climate change particularly sea-level rise and flood-related to extreme rainfall, yet most of the world^s coastal areas are growing faster than the inland population. The precipitation as a flood causatives factor mostly is the main influence of flood occurrence. The topography of an area also contributes to potential flood hazards in the nearest future. The digital elevation model and derivatives are elevations, slope degree, and aspect along with LANDSAT 8 derivatives are the normalized difference vegetation index (NDVI) along with the normalized difference vegetation index (NDWI). The investigation of flood disasters resulting from extreme rainfall and environmental factors regional macro information, in particular, utilize big data analysis with machine learning. The data input to principal component analysis (PCA) to determine the factor contribute to flooding hazard. The method is conducted to reduce the dimensions of data by working with only those indexes whose eigenvalues from PCA are greater than 1. The correlation value between -0.98 to 0.42 with the highest correlation is the elevation and the rainfall factors. In contrast, NDVI and NDWI have a strong negative correlation value. The weighted result shows the main drivers among the factor is rainfall, elevation, NDVI, aspect, slope, and NDWI with value 0.32, 0.29, 0.24, 0.20, 0,14, and -0.21, respectively. Further analysis reveals that the NDWI may not necessary and become the redundant factor for this group analysis. Keywords: topography, rainfall, flood disaster, weight analysis, and principal component analysis Share Link | Plain Format | Corresponding Author (Nanda Khoirunisa)

143	EARTH, ATMOSPHERIC, AND SPACE SCIENCE	ABS-213
The Effects of Grid Shape on Numerical Results: a Case Study of Fluid Flow in Cylindrical Pipe Yusron Feriadi(a)(b*), Umar Fauzi(a), M Rizqie Arbie(a), Fariduzzaman(c) a) Department of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology b) Research Center for Hydrodynamics Technology, National Research and Innovation Agency (BRIN) *yusr004[at]brin.go.id c) Laboratory for Aerodynamics, Aeroelastics and Aeroacoustics, National Research and Innovation Agency (BRIN) Abstract Generating high-quality grids is a challenge in computational simulations because the accuracy of the grid greatly affects the quality of the numerical simulation results. In this study, several grid shapes and sizes were tested to analyze this effect on the simulation. In general, structured and unstructured grids are used in this study, which consist of hexagonal and prism grids. Grid variation is applied to the case of poiseuille flow with a Reynolds number of 250. The pipe used has a length of 30 cm and a diameter of 1 mm, and a pressure difference of 2.4 pascal is applied between the two boundaries so that water flows from the inlet to the outlet. We adopted the finite volume method to solve the Navier-Stokes equation via the PIMPLE algorithm, which is a combination of the PISO algorithm (implicit pressure with splitting of operator) and SIMPLE (semi-implicit method for pressure-linked equations) The simulation results are then compared with the exact results, where the velocity profile around the outlet and the maximum speed are evaluated. To assess the quality of the simulation results, we used two equations, namely L2 norm and absolute error. The simulation shows that a larger number of grids increases the quality of the simulation results and hexagonal grid performance is better than prism one. Keywords: Grid- Poiseuille Flow- Finite Volume Method- PIMPLE Algorithm Share Link | Plain Format | Corresponding Author (yusron feriadi)

144	EARTH, ATMOSPHERIC, AND SPACE SCIENCE	ABS-223
Analysis of Frequency Spectrum, Waveform Cross Correlation and Polarization to Mount Sinabung Tremor during October-November 2013 Qori Fajar Hermawan (a*), Sukir Maryanto (b), Hendra Gunawan (c) (a) Faculty of Mathematics and Natural Sciences, Mulawarman University Jalan Barong Tongkok No. 04, Kampus Gunung Kelua, Samarinda, East Kalimantan, 75123 *qorifajarhermawan[at]fmipa.unmul.ac.id (b) Faculty of Mathematics and Natural Sciences, Brawijaya University Jalan Veteran, Malang, East Java, 65145 (c) Center for Volcanology and Geological Hazard Mitigation (CVGHM) Jalan Diponegoro No. 57, Bandung, West Java, 40122 Abstract Mount Sinabung is an active volcano in North Sumatra Province and showed the eruption activity in 2013. The activity of this volcano could be observed by the seismometers surrounding it. The tremor signal could be observed in the October to November 2013 and it has not been studied before. This study was conducted to analysis the characteristic of Mount Sinabung tremor in the period from October to November 2013 based on the analysis of the frequency spectrum, waveform cross-correlation and polarization. We found 260 data of Mount Sinabung tremor during October to November 2013. The result of frequency spectrum analysis indicated that Mount Sinabung tremors had a wide frequency value, with a value of 0 to 25 Hz and dominant frequency is 1 to 3 Hz. Based on the shape of the frequency spectrum, Mount Sinabung tremor could be distinguished into two types namely, harmonic and nonharmonic tremor. The result of waveform cross correlation analysis showed correlation coefficient values were good enough, from 0.5 to 0.9. The highest correlation value of waveform cross correlation analysis showed the eruption activity on 8 November 2013. Based on the analysis of polarization, tremor source was in the South crater or East-Southeast or 90 degrees to 120 degrees from Station Mardingding. The depth of the tremor source is ranging 0.5 below sea level to 2.4 km above sea level. Keywords: tremor, Mount Sinabung, frequency spectrum, waveform cross-correlation, polarization Share Link | Plain Format | Corresponding Author (Qori Fajar Hermawan)

145	EARTH, ATMOSPHERIC, AND SPACE SCIENCE	ABS-224
Numerical Modeling of Change in Rocks Electrical Conductivity Due to Impurities Rini Oktaviani (a), Umar Fauzi (a*) (a) Physics of Earth and Complex Systems, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology Jalan Ganesha 10, Bandung 40132, Indonesia *umarf[at]itb.ac.id Abstract A better estimation of electrical conductivity of rock is crucial in well-log interpretation, and reservoir evaluation. One of the factors that affects the electrical conductivity is the presence of impurity such as organic material. This study examines the effect of various types and fraction of impurities on the electrical conductivity of rock. Some models with spherical grain which radii vary between 3-9 voxel and impurities which size of 0.5-2 voxel have been developed and the finite element method (FEM) with energy approach is then implemented to calculate the effective electrical conductivity. FEM is first validated by comparing its result with analytical solution for 2D and 3D models. The calculated result from the FEM in 2D and 3D models shows in a good agreement with analytical ones with error of 1.7% and less than 5%, respectively. The electrical conductivity is estimated at different fractions of hematite as impurity. The result shows that the effective electrical conductivity with hematite decreases compared to the effective electrical conductivity without hematite. Perhaps the conductivity of water-filled the pore is higher than the electrical conductivity of the impurity. The effective electrical conductivity obtained from samples with various conductivities of hematite shows that there is an anomaly especially when the conductivity and fraction of hematite are less than 0.02 and less than or equal to 0.04, respectively. The same method will then be applied to real rock samples. Keywords: electrical properties- impurity- finite element method Share Link | Plain Format | Corresponding Author (Rini Oktaviani)

146	EARTH, ATMOSPHERIC, AND SPACE SCIENCE	ABS-225
METAMORPHIC COMPLEX DEFORMATION IN NORTH BANGKA ISLAND BASED ON MACROSTRUCTURES AND MICROSTRUCTURES EVIDENCES Rezki Naufan Hendrawan1, Windi Anarta Draniswari2, Benjamin Sapiie3, Nurcahyo Indro Basuki3 1. Program Studi Teknik Geologi, Institut Teknologi Sumatera, Lampung Selatan, Indonesia 2. Central of Geological Disaster Research, Indonesia Agency of Research and Innovation, Bandung, Indonesia 3. Faculty of Earth Sciences and Technology, Bandung Institute of Technology, Bandung, Indonesia Abstract The northern Bangka Island is composed of Pemali metamorphic complex which is indicated by the collision between Indochina and Sibumasu blocks. These features are interesting to observe because the metamorphic rocks could be recorded in some geological structures at different times. The study began by conducting field observation on Pemali Metamorphic Complex as objects. Field observation aims to collect lithological data, structural data, and oriented rock samples. The results of field pitching were processed to determine macrostructures, microstructures, and mineral distribution. The data was analyzed based on kinematic, descriptive, and deformation mechanisms to determine the deformation patterns that occurred in the study area. Field and oriented thin section data show structures and occurred in different deformation conditions. The analyzed based on macrostructures and microstructures showed that the northern part of Bangka Island experienced three different deformation phases. Deformation begins with the formation of folds that are associated with collisions between Sibumasu-Indochina, followed by a second deformation that forms a fold with different verging. Both deformations are formed in the ductile zone and the brittle-ductile transition zone. The third deformation occurs when rocks have been lifted to the surface by the presence of faults, joints, and veins. The sequence of the deformation model is similar to the deformation experienced in the Bentong-Raub suture zone formed in the shear zone. Keywords: Deformation, microstrucutres, shear zones, Bangka Island, Bentong-Raub Share Link | Plain Format | Corresponding Author (Rezki Naufan Hendrawan)

147	EARTH, ATMOSPHERIC, AND SPACE SCIENCE	ABS-236
Lunar Occultation Light Curve Modeling by using Bayesian Inference Method Agus Triono Puri Jatmiko(a*) a) Observatorium Bosscha, FMIPA, Institut Teknologi Bandung Jl. Peneropongan Bintang, Lembang, Bandung Barat 40391 *agustriono.pj[at]gmail.com Abstract In this work, we present our attempt to develop a code for creating a lunar occultation light curve model by using Bayesian inference method. We describe the mathematical formulae behind the method, our approximation by incorporating a total transmission curve of the telescope and camera system and also a blackbody profile of the occulted stars by the Moon. We also generate synthetic data and test our model to get predetermined parameters. Keywords: Occultation- Bayesian- Light Curve Share Link | Plain Format | Corresponding Author (Agus Triono Puri Jatmiko)

148	EARTH, ATMOSPHERIC, AND SPACE SCIENCE	ABS-248
Near Field and Static Corrections of CSAMT Data Obtain in Volcanic and Geothermal Area Husnul Hamdi, Doddy Sutarno, Wahyu Srigutomo, Enjang Jaenal Mustopa Insitut teknologi Bandung Abstract Controlled source audio-frequency magnetotellurics (CSAMT) is one of electromagnetic sounding method with frequency domain . CSAMT is a frequency-domain electromagnetic sounding technique which uses a fixed grounded dipole as an artificial signal source. Based on the measurement distance variation the transmitter with receiver on CSAMT, there are three zones, near field, transition, and far field. In the far field zone the plane wave assumption already admitted so that the equation for calculating the value of the resistivity can be applied together with the MT method using Cagniard equation. In the area of near field, source effects can still be captured directly by the receiver and the assumption of a plane wave can not be applied so that the data must be corrected. Correction data is also performed at the transition area. The static effects could result for two values of resistivity which can cause large errors in depth estimation and interpretation of the subsurface structure becomes complex. Static correction is done by averaging the resistivity curve in the measured region. Static correction can also be done by comparing the data obtained with the data TEM (Transient Electromagnetic) Keywords: CSAMT, Volcanic, Geothermal Share Link | Plain Format | Corresponding Author (Husnul Hamdi)

149	ENVIRONMENTAL SCIENCES	ABS-268
Heavy Metals Accumulation in Lichens Parmeliaceae and Mahogany Bark as an Indicator of Air and Pollution Levels in Several Locations in Bandung City Putri Nurul Fitriyyah (a*), Taufikurahman (a) a) School of Life and Technology, Bandung Institute of Technology Jalan Ganesha 10, Bandung 40132, Indonesia *putrinurullfitriyyah[at]gmail.com Abstract Increasing number of motorized vehicles and industrial sector in Bandung city can be a source of air pollutants, one of the sources of air pollutants that very harmful to human health is heavy metal, so air quality monitoring is needed. Lichens and bark are known as biomonitor that can be used on a large area scale and accumulate pollutants over a long period of time. The purpose of this study is to determine the concentration of heavy metals accumulated by lichens and tree bark in the Bandung city, analyzing the influence of heavy metal accumulation on diversity and the area of lichens cover on tree trunk that can be used to determine air quality in several locations in Bandung city. In this study, lichens from mahogany tree and mahogany bark was collected using plot-less sampling at a height of at least 100 cm using a 20x32 cm2 quadrat size above the ground from 25 sampling stations that distribute at five locations in Bandung city, including city parks, urban forest park and bus station, then the sample was analyzed using AAS (Atomic Absorption Spectrophotometry) to measure the concentration of heavy metals in lichens and bark samples. The results showed lichens and bark from Persib city park (PCP) containing the highest Cr (17.08 \mu g/Kg for- 30.03 \mu g/Kg) and Pb (24.38 \mu g/Kg- 15.49 \mu g/Kg), while lichens and bark from ir.H.Djuanda forest park (DFP) had the lowest Cr concentration (3.74 \mu g/Kg- 3.56 \mu g/Kg) and Pb (3.74 \mu g/Kg- 2.06 \mu g/Kg). The highest lichens diversity index with a moderate category is found in DFP (H^ = 1.39), while PCP has the lowest lichens diversity index (H^ = 0.02). On the DFP is found Parmotrema sp. which belongs to the sensitive category lichens, while Parmelia sp. found at all sampling sites. Based on the results of the PCA analysis, the accumulation of heavy metals in lichens and bark samples of tree trunks is influenced by environmental conditions, in this case the level of traffic density, and bark pH. The accum Keywords: Lichens, Mahogany Bark, Lichens Diversity Index Share Link | Plain Format | Corresponding Author (Putri Nurul Fitriyyah)

150	ENVIRONMENTAL SCIENCES	ABS-270
Productivity and growth rate of fish rearing in SMART Floating Net Cage in Jatiluhur Reservoir, West Java, Indonesia Andri Warsa(a*) Lsimining Pujiyani Astuti (a) Didik Wahju Hendro Tjahjo (a) Tarzan Sembiring (b) a) Research Center for Conservation of Marine and Inland Water Resources Cibinong Science Center, Jl. Jakarta-Bogor Km 48 Cibinong, West Java, Indonesia 16911 *andriwarsa[at]yahoo.co.id b) Research Center for Environmental and Clean Technology Jl. Cisitu lama 21/154 D, Bandung, West Java - Indonesia 40135 Abstract The over-carrying capacity of aquaculture activity caused water quality degradation as impacted by waste loading from uneaten feed and fish metabolism. The need for ecologically friendly technology can diminish the pollutant for sustainable aquaculture activity. SMART Floating Net Cage (FNC) is an aquaculture technology that combines double net and bag collection waste and filtration systems by the plant. The research aims to know the known growth rate and productivity of SMART FNC. The study was done in Jatiluhur Reservoir in February-November 2021 in Pasir Canar Zone. The cage was using have 14x7x5 m in dimensions with a double net. The inner net was divided with a 7x7x3 m dimension for common carp rearing and the outer net with 14x7x5 m for Nile tilapia rearing. The weight of common carp and Nile tilapia seeds were 200 and 150 kg, respectively. The growth rate of common carp and Nile tilapia were 2,4-4,3 dan 2,0-6,3 g/day, respectively, with 1578 and 400 kg/period for harvest. Keywords: productivity- aquaculture- sustainable- eco-friendly Share Link | Plain Format | Corresponding Author (Andri Warsa)

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