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Pembuatan Model Fisis Letusan Gunung Lumpur Bledug Kuwu dan Pemodelan Numerik Untuk Mengetahui Kecepatan Perambatan Gelombang Seismiknya Pohan, Ahmad Fauzi; Suryanto, Wiwit; Wahyudi, Wahyudi
Jurnal Fisika Indonesia Vol 20, No 2 (2016)
Publisher : Department of Physics Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1755.943 KB) | DOI: 10.22146/jfi.28028

Abstract

Media fisis menggunakan akuarium berukuran 59 × 59 × 37,3 cm yang diisi material dari lumpur Bledug Kuwu. Sumber letusan dihasilkan dari tekanan kompresor yang dapat diatur kedalaman dan sudut sumbernya. Sinyal seismik direkam menggunakan geophone komponen vertikal sebanyak 3 buah dengan durasi perekaman selama 10 dan 5 detik. Data diambil dengan frekuensi sampel 2 dan 4 kHz untuk masing-masing durasi perekaman. Pemodelan numerik dilakukan menggunakan metode finite-difference orde-4 teknik convolutional perfectly matched layer (CPML) untuk mencocokkan hasil dari pemodelan fisis. Konfigurasi sumber dan geophone dibuat sesuai dengan pemodelan fisisnya. Hasil model fisis diperoleh kecepatan perambatan gelombang-P pada medium lumpur Bledug Kuwu adalah sebesar 48,74 m/s, dengan frekuensi dominan antara 20 sampai 25 Hz. Hasil perbandingan antara seismogram model fisis dan seismogram model numerik diperoleh parameter kecepatan gelombang-S sebesar 28,14 m/s, densitas lumpur sebesar 1200 Kg/m3, dan conduit dari Bledug Kuwu membentuk sudut 30° terhadap arah vertikal, dengan hasil korelasi antara model fisis dan numerik sebesar 0,9. 
ANALISIS DAN MODEL INVERSI GAYA BERAT 2D UNTUK PENAMPAKAN SESAR PALU KORO DI SULAWESI TENGAH INDONESIA Jamidun, Jamidun; Rusydi, M.; SB, Kirbani; P, Subagio; Suryanto, Wiwit
Natural Science: Journal of Science and Technology Vol 8, No 1 (2019): Volume 8 Number 1 (April 2019)
Publisher : Univ. Tadulako

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (451.862 KB)

Abstract

Analisis dan modeling mengenai struktur geologi Pulau Sulawesi khususnya wilayah Sulawesi Tengah sangat menarik sebab memiliki kompleksitas yang tinggi sebagai akibat interaksi dinamis dari tiga lempeng utama dunia. Ketiga lempeng tersebut yakni lempeng India Australia, lempeng Pasifik dan lempeng Eurasia yang dalam pergerakannya saling bertemu yang mengakibatkan daerah ini mengalami deformasi kerak bumi yang aktif. Salah satu bentuk deformasi dari gerakan dinamik adalah terbentuknya sesar Palu Koro. Metoda yang digunakan untuk mengkaji sesar tersebut digunakan metoda gayaberat. Hasil yang diperoleh menunjukkan bahwa sesar Palu Koro merupakan sesar geser mengiri dan normal. Model patahan bawah permukaan sesuai dengan penampakan morfologi topografi daerah penelitian. Bagian struktur bawah permukaan telah mengalami deformasi yang kuat dimana semua model strukturnya berbentuk struktur sekunder tidak ditemukan lagi struktur primer. Didapatkan pula batuan intrusi berkisar dari dua sampai tiga intrusi yang terlihat pada sayatan AA?. Formasi batuannya berjumlah enam jenis, yaitu batuan aluvium, formasi pakuli, formasi latimojong, kompleks wana, kompleks gumbasa dan batuan intrusi.
Inverse Modeling Using Taylor Expansion Approach and Jacobi Matrix on Magnetic Data (Dyke/Magma Intrusion Cases) Suprianto, Agus; Wahyudi, Wahyudi; Suryanto, Wiwit; Setiawan, Ari; Adhi, Aryono; Priyantari, Nurul; Supriyadi, Supriyadi; Subekti, Agus
Scientific Journal of Informatics Vol 6, No 2 (2019): November 2019
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/sji.v6i2.19798

Abstract

The mathematical modelling of geological structures, i.e. magma intrusion or dyke, has been done,  based on magnetic data with inversion techniques using MatLab. The magnetic equation is a non-linear equation, and completion is done using a linear approach to non-linear mathematical models of magnetic data using the Taylor expansion approach and Jacobi Matrix. The first step of this research is to make synthetic data forward modelling from the magnetic equation of magma intrusion or dyke cases without errors, and the next stepping then add errors to the data. The next step is to do an inversion to get the parameters sought, i.e. depth and angle of the magma intrusion, by giving initial guesses, and then re-correct iteratively until convergent results are obtained. Finally, parameters of slope dyke or thin magma intrusion and its depth can be determined. The results obtained indicate that this technique can be used to get physical parameters sought from magnetic data for simple geological cases, i.e. dyke and magma intrusion.
Microtremor Data to Strengthen the Students’ Mastery of Materials in the Implementation of Integrated Physics Learning Ningrum, Rohima Wahyu; Fauzi, Hendra; Suryanto, Wiwit; Mei, Estuning Tyas Wulan; Amelia, Risky Nuri
Jurnal Penelitian Fisika dan Aplikasinya (JPFA) Vol 10, No 1 (2020)
Publisher : Universitas Negeri Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26740/jpfa.v10n1.p81-89

Abstract

A geophysical research has been conducted to determine the level of hazard vulnerability in West Halmahera by using microtremor data. Microtremor data are analyzed using the Horizontal to Vertical Spectral Ratio (HVSR) method and it is processed using Geopsy software to know hazard vulnerability level in the region . Data analysis and processing are used as sources of information in physics learning materials using an integrated learning model. Research objectives are to train the students to understand the materials in the fields of study and to enhance other discovery ideas.This research method uses the correlational method and the type of research is experimental research. The research design is an uniquecase research design and the instrument used is tests and questionnaires. The results of this research indicate that the microtremor data using integrated learning models of integrated types have effect on the students’ Mastery of materials in the implementation of physics learning. The effect of the integrated learning model of integrated type on the students’ Mastery of materials on the concepts of vibration and waves is 16% and it is in low category. Whereas, the students' responses to integrated learning model of integrated type are quite fun and it can help to improve their mastery of the material on the concepts of vibration and waves.
GRAV3D Validation using Generalized Cross-Validation (GCV) Algorithm by Lower Bounds Approach for 3D Gravity Data Inversion Adhi, Mochamad Aryono; Wahyudi, Wahyudi; Suryanto, Wiwit; Sarkowi, Muh
Scientific Journal of Informatics Vol 5, No 2 (2018): November 2018
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/sji.v5i2.16736

Abstract

The completion of gravitational data inversion results in a smooth recovered model. GRAV3D is one software that can be used to solve 3D inversion problems of gravity data. Nevertheless there are still fundamental problems related to how to ensure the validity of GRAV3D to be used in 3D inversion. One approach used is to use lower bounds as inversion parameters. In this study lower bounds are set from  to . The results obtained show that the use of lower bounds decreases resulting in a larger data misfit which means that the more data that meets the tolerance calculation, the better recovered model produced.
Inverse Modeling Using Taylor Expansion Approach and Jacobi Matrix on Magnetic Data (Dyke/Magma Intrusion Cases) Suprianto, Agus; Wahyudi, Wahyudi; Suryanto, Wiwit; Setiawan, Ari; Adhi, Aryono; Priyantari, Nurul; Supriyadi, Supriyadi; Subekti, Agus
Scientific Journal of Informatics Vol 6, No 2 (2019): November 2019
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/sji.v6i2.19798

Abstract

The mathematical modelling of geological structures, i.e. magma intrusion or dyke, has been done,  based on magnetic data with inversion techniques using MatLab. The magnetic equation is a non-linear equation, and completion is done using a linear approach to non-linear mathematical models of magnetic data using the Taylor expansion approach and Jacobi Matrix. The first step of this research is to make synthetic data forward modelling from the magnetic equation of magma intrusion or dyke cases without errors, and the next stepping then add errors to the data. The next step is to do an inversion to get the parameters sought, i.e. depth and angle of the magma intrusion, by giving initial guesses, and then re-correct iteratively until convergent results are obtained. Finally, parameters of slope dyke or thin magma intrusion and its depth can be determined. The results obtained indicate that this technique can be used to get physical parameters sought from magnetic data for simple geological cases, i.e. dyke and magma intrusion.
The Effect of Differences Leachate Concentration and Material Properties on Electrical Conductivity of Volcanic Deposits – Case Studies Piyungan Landfill Bantul Yogyakarta Parhusip, Jaingot A.; Harijoko, Agung; Eka Putra, Doni Prakasa; Suryanto, Wiwit
Journal of Applied Geology Vol 1, No 1 (2016)
Publisher : Geological Engineering Department Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (886.368 KB) | DOI: 10.22146/jag.26956

Abstract

Monitoring at the contaminated subsurface soil, have been conducted by using the geophysical surface method, especially for geoelectrical resistivity method. Monitoring is commonly conducted by using geoelectrical resistivity through measuring the value of Electrical Resistivity (ER) or Electrical Conductivity (EC) of leachate contaminated soil layer. EC measurement value of soil is affected by many factors, among others, particle conduction of soil materials, surface conduction, fluid conduction in the pores as well as the effect of particle shape and soil materials. Piyungan landfill is the main disposal site of Yogyakarta municipal solid waste. This landfill located mainly on the tertiary rocks of volcanic rocks and its weathering products. In order to improve the accuracy of geoelectrical measurements on resistivity in monitoring soil layers from contaminated leachate on this area, this research conducted several measurements on physical properties of soil sample and electrical properties of leachate in the saturated soil samples. The measurement of physical properties includes: porosity, clay content, particle content, and cation exchange capacity (CEC) value. The soil samples were collected from 3 locations around Piyungan Landfill. Type of soils are taken from the alluvial deposits (Sample B), weathered tuffaceous sandstone-claystone (Sample D), and weathered andesitic breccia (Sample F). Samples were made in containers, saturated with aquades-leachate solution with 12 different concentration levels. Electrical conductivity (EC) was measured by using Soil Box Miller and Geoelectric Resistivity Oyo McOhm. According to results of physical properties analysis, the grain size of soils are dominantly sandy clayey silt in grain size distribution, with clay content ranging from 33.0--38.4 %, the CEC values ranging from 26.8--52.7 meq/100 gr, and the porosity of samples B, D and F is 58.85 %, 55.30 %, 59.24 %, respectively. Based on the experiments with 12 different leachate concentrations, there is a linear increase in EC of 0.718mS/cm for every increase in electrical conductivity pore fluid (ECf ) 1 mg/l in samples B, while in samples D and F are 0.492 mS/cm and 0.284 mS/cm respectively. Plotting the data of EC vs ECf for each samples and ER vs ECf , it can be concluded the slope ofDEC/DECf differ for each samples and the electrical conductivity value of different concentration of leachate is very sensitive for alluvial deposits compare to the weathered tuffaceous sandstone-claystone and weathered volcanic breccia deposits.