Udi Harmoko
Departemen Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro, Semarang

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RELOKASI HIPOSENTER GEMPA MIKRO DENGAN METODE SED DAN JHD SEBAGAI ANALISIS RESERVOAR AREA PANAS BUMI-X Idat, Cassandra Fitrianna; Harmoko, Udi
YOUNGSTER PHYSICS JOURNAL Vol 5, No 3 (2016): Youngster Physics Journal Juli 2016
Publisher : Jurusan Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro

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Mount Wayang and Windu, located about 35 kilometers south of Bandung, the capital of West Java, Indonesia. This area included in a set of active hydrothermal geothermal area around South Bandung. Microearthquake network is a collection of microearthquake recording station that has been used from 1960. Data from this network of micro earthquakes can predict permeable structure in the reservoir, which is as monitoring the pattern of fluid flow and reservoir limits, called cap rock that is impermeable. Analysis of seismic activity in micro earthquake data that is in determining the location of the hypocenter, for determining the location of the hypocenter can complicate the interpretation of the structure. Methods Single Event Determination (SED) and the Joint Hypocenter Determination method (JHD) can optimize the location of the hypocenter with a correction to the 1-D velocity model. There are 160 events were recorded from January 2014 to April 2014. The data is processed so that there are 55 local earthquake event data were inverted to obtain new hypocenter location using the SED and JHD. The second result of inversion produces more accurate hypocenter locations with a reservoir that has a moment epicenter distribution pattern direction Northwest - Southeast. Long reservoir SED results estimated 25 km with a depth of permeable zone of 20 km, whereas after correction obtained JHD same length but permeable zone is detected to a depth of 26 km. Keywords: Joint Hypocenter Determination, Single Event Determination, Microearthquake, Geothermal.
PERBANDINGAN POST STACK TIME MIGRATION METODE FINITE DIFFERENCE DAN METODE KIRCHOFF DENGAN PARAMETER GAP DEKONVOLUSI DATA SEISMIK DARAT 2D LINE “SRDA” Dynza Anggary, Sheyza Rery; Danusaputro, Hernowo; Harmoko, Udi
YOUNGSTER PHYSICS JOURNAL Vol 4, No 1 (2015): Youngster Physics Journal Januari 2015
Publisher : Jurusan Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro

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ABSTRACT           Analysis on Post Stack Time Migration (Post-STM) with finite difference method and Kirchoff method with determine gap parameter on deconvolution after stack had been applied to 2D land seismic at line ?SRDA?. This research had purpose to applied seismic data processing to get subsurface imaging with high signal-to-noise ratio and analyze how the gap parameter corresponding on deconvolution after stack, and to determine which the appropriate method of migration between migration finite difference and Kirchoff migration in Post Stack Time Migration (Post-STM).         Gap parameter selected in the deconvolution process after the stack is a gap 24, 32 and 64. Based on the analysis of the three parameters were chosen gap 32 which has the best results because the gap 32 in accordance with the conditions of the data and the effect does not change the condition of reflectors on seismic cross section. While the migration phase, the results better structure when subjected Kirchoff migration method, because it is more obvious than the reflector continuity migration finite difference method. Keywords: Deconvolution after stack, Post Stack Time Migration
VERTICAL TRANSVERS ISOTROPY (VTI) PRE STACK DEPTH MIGRATION ANISOTROPI UNTUK PENCITRAAN STRUKTUR BAWAH PERMUKAAN YANG LEBIH AKURAT Rasid, Ibnu; Harmoko, Udi; Setyawan, Agus; Suroso, Teguh
YOUNGSTER PHYSICS JOURNAL Vol 1, No 1 (2012): Youngster Physics Journal Oktober 2012
Publisher : Jurusan Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro

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Anisotropic Pre Stack Depth Migration method has been carried out for 2D seismic reflection data on Line ?IR? The simplest form of anisotropic media (VTI (Vertical Transverse Isotropy) was used. Theoretically, this form requires two parameters to describe the media, those are ? (delta) and ? (epsilon). ? is an anisotropy parameter that describe velocity variation near to vertical while ? is an anisotropy parameter that describe velocity variation near to horizontal. The anisotropic Pre Stack Depth Migration produce a section which has corrected build up image and has change to be the true of reflector in 67 m of depth. Base on well and seismic data calculation process, an anisotropic parameter is in the range of 0.050-0.058. Generally, Anisotropy Pre Stack Depth Migration method gave better result than isotropy Pre Stack Depth Migration. Key Word: Anisotropy, Pre Stack Depth Migration, VTI, delta, epsilon
IDENTIFIKASI SIFAT FISIS BATUAN RESERVOIR KARBONAT MENGGUNAKAN INVERSE ACOUSTIC IMPEDANCE (AI) MODEL SPARSE SPIKE PADA LAPANGAN “ABDUH” FORMASI KUJUNG CEKUNGAN JAWA TIMUR UTARA Abdurrahman, Saad; Harmoko, Udi; Ardiyanto, Agung
YOUNGSTER PHYSICS JOURNAL Vol 6, No 2 (2017): Youngster Physics Journal April 2017
Publisher : Jurusan Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro

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Physical rocks properties identification on "ABDUH" field, North East Java Basin has been done by acoustic impedance seismic inversion. The research aim conducted to predict the physical properties of rock by  acoustic impedance inversion value and the porosity distrubution by linier programming sparse spike. Sparse spike linear programming method assumes that a reflectifity regarded as the model a series of rarely spike and the big value deconvoluted with a new spike smaller than before maked it more accurated. This study used at single well and seismic 3D data post stack time migration is the area on research. Then with assumes a linear relationship between acoustic impedance and log porosity log based crossplot, obtained linear equation which was used to get the distribution of porosity from the distribution of acoustic impedance. Inversion results show the distribution of reefs on Kujung Reef formation has the porosity value 21-27% and the acoustic impedance vaue 17.000 to 28.000 ft/s.g/cc.Keywords: Acoustic Impedance, Kujung Reef, Porosity, Linier Programming Sparse Spike Inversion
IDENTIFIKASI STRUKTUR BAWAH PERMUKAAN MENGGUNAKAN METODE GEOLISTRIK KONFIGURASI SCHLUMBERGER AREA PANAS BUMI KENDALISODO KECAMATAN BERGAS KABUPATEN SEMARANG Guenergar, Alchacindy; Harmoko, Udi; Widada, Sugeng
YOUNGSTER PHYSICS JOURNAL Vol 3, No 3 (2014): Youngster Physics Journal Juli 2014
Publisher : Jurusan Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro

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The research has been done by using geoelectric method schlumberger configuration at Kendalisodo geothermal manifestation . The purpose of researching is to know layer of subsurface structure which control Kendalisodo geothermal manifestation.Measurement has been conducted using schlumberger configuration. The data observation conducted at 4 points  around by Kendalisodo hot springs . Data processing conducted using software IP2WIN. Data measurement in the field are potential differences and currents which can be used to calculate apparent resistivity value. After apparent resistivity value is created then processed using IPI2WIN program to know resistivity value in each layer with geology information validation. The results of the study showed seven  geoelectric layer of rock that is composed of layers of topsoil, sandstone, breccia, tuffan sandstone, breccia, tuff, and  combined Sandstone and breccia with resistivity values and different thicknesses. Interpretation of manually indicate the presence of  down faults that are weak zone where the fluid surface discharge.Keywords : geoelectric, geothermal, and Kendalisodo
INTERPRETASI STRUKTUR BAWAH PERMUKAAN DI MUARA SUNGAI PROGO MENGGUNAKAN METODE MAGNETIK Andri, Dewi; Irham, Muhammad; Harmoko, Udi
YOUNGSTER PHYSICS JOURNAL Vol 5, No 4 (2016): Youngster Physics Journal Oktober 2016
Publisher : Jurusan Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro

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Progo fault is one of the active faults located in the south of Yogyakarta. Progo fault is suspected that located in Progo River estuary area, Banaran, DIY. However, studies are still needed to support the scientific basis of the position and the type of fault in Progo River estuary. Magnetic survey has been carried out in DIY Progo River estuary to determine the subsurface structure in the area. Data needed in the processing of magnetic data is a magnetic anomaly data obtained from the values of the total magnetic field strenghthas been corrected. In this study, magnetic data acquisition was carried out in 97 points by using a PPM (Proton Precession Magnetometer) geometrics 856X. Data Processing began with International Geomagnetic Reference Field (IGRF) correction and diurnal correction to get the total magnetic anomaly. The total magnetic anomaly contour created by using Surfer that has been used to process upward continuation and then made reduction to the poles. The result of research showed the total magnetic anomaly closure pair of positive and negative indicated a fault zone below the surface. Mag2D used to create 2D modelling to obtain the subsurface structure and susceptibility values. To reinforce the results of subsurface structure, 3- modelling has been created by used Mag3D. In 2D-modelling of subsurface structure is obtained in the form of fault zones in the west an the east of the River Progo. The interpretation is reinforced by the result of 3D-modelling in the area. There are tworeserve faults in Progo River estuary area, first in the west of the Progo River and second in east Progo River to a depth of 1000 meters.
PEMODELAN 2D SISTEM PANA BUMI DAERAH GARUT BAGIAN TIMUR MENGGUNAKAN METODE MAGNETOTELURIK Salam, Riznia Aji; Harmoko, Udi; Yulianto, Tony
YOUNGSTER PHYSICS JOURNAL Vol 6, No 2 (2017): Youngster Physics Journal April 2017
Publisher : Jurusan Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro

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This research was conducted in the eastern part of the Garut area using magnetotelluric method that aims to create 2D model of the geothermal system based on distribution of rock resistivity value. Magnetotelluric method is used because it is able to identify subsurface structure to a depth of thousands of meters. In this research, the data measured from 9 different targets area and processed based on the flow such as converting time domain data into the frequency domain, identify noise data, perform two-dimensional inversion modeling and create geothermal systems. Based on the results, also compared with the interpretation of geological data and geochemistry of rocks known clay cap, reservoir, and hot rock. Furthermore, Clay cap has a value of 4-32 ?m resistivity on depth of 3000 m. Reservoir rock with resistivity value of 64-512 ?m at a depth of 1500-5000 m. While hot rock with 1024-8192 ?m resistivity value is under the reservoir rock.Keywords: Magnetotelluric, Eastern section of the Garut, geothermal system, resistivity
ANALISA PRESERVASI AMPLITUDO DAN RESOLUSI SEISMIK PADA DATA HASIL RECONVOLUTION LAPANGAN “X” CEKUNGAN SUMATERA TENGAH Muhidin, Agus; Harmoko, Udi; Danusaputro, Hernowo; Saputra Haris, Moh. Irfan
YOUNGSTER PHYSICS JOURNAL Vol 4, No 1 (2015): Youngster Physics Journal Januari 2015
Publisher : Jurusan Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro

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Structure interpretation of post-stack seismic data to delineate lithology boundary sometimes face difficulties in tracking reflector continuity, this is due to limitation of vertical resolution. Reconvolution method has been applied to fix vertical seismic resolution. In order to validate the function reconvolution to amplitude related interpretation, amplitude variation with offset (AVO) has applied to geology model.Reconvolution method was applied by increasing dominant frequency of seismic data and capable to minimize tuning thickness zone of geology model has been made. Modeling geology based on average of P velocity, S velocity, and density from field ?X? well data and estimating P velocity, S velocity and density for fluid condition of reservoir. AVO analysis has been applied to validate how far reconvolution method capable to maintain amplitude behavior, AVO analysis using Zeoppritz equation in 10 to 30 degree angle and using intercept attribute (A), gradient (B) and product (A*B). Reconvolution method has used 50 Hz, 60 Hz, 65 Hz, and 70 Hz of wavelet.Reconvolution method capable to fix vertical seismic data resolution, it can be seen by decreasing of tuning thickness from 16 to 14 meters. Based on AVO analysis that be used for validate reconvolution method is showing intercept (A) and gradient (B) value be affected by fluids condition in reservoir and presence the random noise in the seismic data. Intercept (A) and gradient (B) for reconvolved data do not have significant changes. However, wavelet has used in reconvolution that possess the smallest error value is wavelet with dominant frequency in 60 Hz and 65 Hz. Keywords: Structure interpretation, Tuning thicknes, Recovolution, and AVO analysis
INTERPRETASI STRUKTUR BAWAH PERMUKAAN BERDASARKAN DATA GEOMAGNETIK PADA DAERAH MATA AIR PANAS JATIKURUNG KABUPATEN SEMARANG Fitria, Laela; Yulianto, Tony; Harmoko, Udi
YOUNGSTER PHYSICS JOURNAL Vol 4, No 4 (2015): Youngster Physics Journal Oktober 2015
Publisher : Jurusan Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro

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The interpretation of subsurface structure and the identification of caused of the hot springs Jatikurung by using magnetic method have been successfully carried out. In this study, magnetic data acquisition was carried out in 71 points by using a PPM (Proton Precession Magnetometer) geometrics type of GSM 19T models to get the values of the total magnetic field. Data processing began with IGRF (International Geomagnetic Reference Field) correction and diurnal correction to get the total magnetic anomaly. The corrected data has been used to create total magnetic anomaly contour. The total magnetic anomaly contour has been used to process reduction to plan surface. The result of reduction to plan surface has been used to create a contour upward continuation and then made reduction to the poles. The result of research showed the total magnetic anomaly closure pair of positive and negative indicated a fault zone below the surface. The closure pair of positive and negative close to the manifestation was made an incision to determine the subsurface structure of the region by creating a model of 2-dimensional (2D) using software Mag2DC. In 2D modeling result show that there was a fault zone about 1200 meters depth. At a depth of 326 to 1200 meters was interpreted as a cap rock with a value 0.2926 (SI). The exhibition of the hot springs Jatikurung was interpreted by the finding of adjacent fault with igneous intrusion which was estimated to save the residual of magma that can be used as a heat source.
INTERPRETASI LAPISAN BAWAH PERMUKAAN DENGAN TRANSFORMASI PSEUDOGRAVITASI BERDASARKAN DATA GEOMAGNETIK PADA MANIFESTASI MATA AIR PANAS KENDALISODO KABUPATEN SEMARANG Susilo, Nanang Didik; Nurwidiyanto, Muhammad Irham; Harmoko, Udi
YOUNGSTER PHYSICS JOURNAL Vol 5, No 4 (2016): Youngster Physics Journal Oktober 2016
Publisher : Jurusan Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro

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Kendalisodo?s area has geological structures which formed by volcanic Ungaran there are hot springs manifestations has been do secondary geomagnetic data processing obtained in the measurement in Kendalisodo Semarang District. The study aims to interpret the subsurface conditions around the hot springs area Kendalisodo caused the emergence of the hot springs in the area. A total of 63 data points that have been corrected International Geomagnetic Reference Field (IGRF) and daily variation correction is used to make the contours of the total magnetic field anomalies. Contour anomaly magnetic field is then processed using a upward continuation filter, reduction to the pole filter, pseudogravity transformation filter, horizontal and second vertical gradient derivative filter. The results of data processing in the form of total magnetic field anomalies that indicate closure pair of positive and negative closure indicating the fault zone below the surface. This interpretation is supported by the contour anomalyand pseudogravity contour, horizontal gradient which shows that there is a fairly strong density contrast and vertical gradient analysis of the order of two indicates that the fault is a reverse fault type. The interpretation is reinforced also by modeling results that indicate a fault that appears on the rock Gajahmungkur and kaligetas formations in the area Kendalisodo trending northwest-southeast. This fault zone is a media outlet fluid to the surface that appears as the source of the hot springs