Agung Setianto, Agung
Jurusan Teknik Geologi Universitas Gadjah Mada Yogyakarta

Published : 9 Documents
Articles

Found 9 Documents
Search

PEMANFAATAN CITRA DIGITAL ELEVATION MODEL (DEM) UNTUK STUDI EVOLUSI GEOMORFOLOGI GUNUNG API MERAPI SEBELUM DAN SETELAH ERUPSI GUNUNG API MERAPI 2010 Rahanjani, Yustian Ekky; Setianto, Agung; Srijono, Srijono
Seminar Nasional Informatika (SEMNASIF) Vol 1, No 5 (2012): Geoinformatic And GIS
Publisher : Jurusan Teknik Informatika

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Gunung api Merapi adalah satu dari gunungapi teraktif di dunia. Erupsi G.Merapi sepanjang 26 Oktober hingga 4 November 2010 menyebabkan banyak korban dan perubahan morfologi yang signifikan di sekitar tubuh gunung api. Hal ini mendorong peneliti untuk melakukan penelitian mengenai perubahan morfologi karena erupsi. Daerah penelitian berada di lereng selatan G.Merapi, khususnya pada bagian channel dan overbank Kali Gendol. Maksud dari penelitian evolusi geomorfologi G. Merapi ini adalah mengetahui perubahan geomorfologi yang terjadi akibat erupsi G. Merapi 2010 . sedangkan tujuan penelitian ini adalah menganalisis kondisi geologi setelah erupsi G. Merapi 2010, perubahan pola kontur setelah erupsi G. Merapi 2010, dan perubahan pola penyaluran setelah erupsi G. Merapi 2010. Pada penelitian ini, kami menggunakan DEM pada tanggal 6 Oktober 2010 dan 9 November 2010 untuk membandingkan dan menganalisis kondisi sebelum dan setelah erupsi. Penelitian mengombinasikan hasil pengolahan data Digital Elevation Model (DEM) multitemporal, yaitu DEM sebelum erupsi dan DEM sesudah erupsi dan data lapangan berupa data litologi dan morfologi untuk menganalisis peta geomorfologi, mendeterminasi perubahan elevasi, peta pola penyaluran sebelum dan setelah erupsi, , dan peta kontur sebelum dan setelah erupsi. Setelah itu, dibuat analisis perubahan jarak kontur pada tiap satuan geomorfologi, analisis fluktuasi perubahan elevasi pada tiap satuan geomorfolgi, dan analisis perubahan azimuth aliran sungai pada tiap satuan geomorfologi. Berdasarkan hasil pengolahan DEM dan data lapangan, daerah penelitian dapat dibagi menjadi dua satuan litologi yaitu Satuan Kubah Lava dan Satuan Piroklastik. Kemudian, daerah penelitian juga dapat dibagi menjadi 6 satuan geomorfologi pada DEM sesudah erupsi, yaitu Satuan Dataran, Satuan Perbukitan Bergelombang Lemah, Satuan Perbukitan Bergelombang Lemah-Kuat, Satuan Perbukitan Bergelombang Kuat, Satuan Perbukitan Berlereng Curam, dan Satuan Pegunungan Berlereng Sangat Curam. Dari hasil analisis pola kontur dan pola aliran sungai didapat bahwa arah displacement sesuai kontur menurun pada model tidak sepenuhnya sama dengan arah displacement material erupsi G. Merapi. Hal ini dikarenakan massa jenis yang tidak rata akibat transportasi material tersebut, faktor morfologi asal, dan rekayasa manusia (rumah-rumah penduduk yang menjadi barrier aliran piroklastik).
Determination of suitable groundwater quality for agriculture by using GIS application in Bantul Regency, Yogyakarta Special Province, Indonesia Kong, Chhuon; Hendrayana, Heru; Setianto, Agung
Journal of Applied Geology Vol 5, No 2
Publisher : Geological Engineering Department Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (3158.577 KB) | DOI: 10.22146/jag.7208

Abstract

irrigation purposes within Bantul area which is located on Yogyakarta Volcanic Groundwater Basin, 47 existing data points were used complementary with the results of 30 groundwater samples analysis which were collected from dug and tub wells in various locations of study area. ECw, TDS, pH and major cations: Na+, Ca2+, Mg2+, K+,and anions: Cl????, HCO???? 3 , SO2???? 4 , NO???? 3 were analyzed as evaluation index. The relative tendency of ion in epm shows Ca2+>K+>Na+>Mg2+ and HCO???? 3 >Cl????>SO2???? 4 . Variations in groundwater composition by using Mg/Ca vs. Na/Ca molar ratio indicates that the groundwater is close to silicate rock with influence of clastic carbonate rock. Higher salinity approach to the west of the Bantul indicates that groundwater quality is controlled by clastic carbonate rock and expose limestone of Sentolo hills. Groundwater samples fall under class I suggested that groundwater is good and suitable for irrigation based on Doneen’s classification of permeability index and 78.37% is in excellent category by Wilcox classification on N%. According to the SAR values plotted in the USSL diagram, the majority of the groundwater samples belong to C2-S1 and C2-S2 class, indicating medium salinity and low sodium water which can be used for irrigation with little danger. The suitability of groundwater quality for agriculture is determined by thematic maps produced from ArcGIS Spatial Analyst based on FAO guideline. Salinity is the significant problem that has slight to moderate restriction effect on crops productivities in this area. The ECw map indicates that good groundwater quality for crops is at the middle to the east of study area close to Opak River, while at the western irrigation water is affected but yielding no reduction on rice productivity. However, it has slight to moderate restriction on sensitive crops indicated in thematic map of crops land with different yield potential. The agricultural land in which has yield potential of 100%, 90% and 75% is about 2727.90 ha (38.56%), 735.49 ha (10.39%) and 208.98 ha (2.95%) of the study area respectively. Key words: Irrigation groundwater quality, total dissolved solids (TDS), electrical conductivity (EC), evaluation index, ArcGIS Spatial Analyst, FAO guideline, yield potential.
SITE RESPONSE CHARACTERISTICS OF H/V SPECTRUM BY MICROTREMOR SINGLE STATION OBSERVATIONS AT PALU CITY, INDONESIA Thein, Pyi Soe; Pramumijoyo, Subagyo; Brotopuspito, Kirbani Sri; Wilopo, Wahyu; Kiyono, Junji; Setianto, Agung
Journal of Applied Geology Vol 5, No 1
Publisher : Geological Engineering Department Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1018.266 KB) | DOI: 10.22146/jag.7202

Abstract

In this study, we estimated predominant period of an H/V spectrum in Palu City, Indonesia, by using microtremor single station observations. Sulawesi Island, eastern Indonesia, is located at the junction between the converging Pacific-Philippine, Indo- Australian Plates and the Eurasian Plate. One of the major structures in Central Sulawesi is the Palu- Koro Fault system, which extends NNW-SSE direction and cross-cuts Sulawesi along more than 300 km from the North Sulawesi trench passing southward through Palu Bay then turn to the southeast, connecting to the Matano and Lawanopo Faults and further eastward both faults join to Tolo trench. Several earthquakes have been known along Palu-Koro Fault system such as Gimpu earthquake (1905), Kulawi earthquake (1907), Kantewu earthquake (1934), and offshore Donggala earthquake (1968) which caused tsunami that destroyed 800 houses and killed 200 people at Donggala district. Palu City, located at the northern tip of Palu depression, is a capital of the Central Sulawesi Province. It is located in the active seismic zone of the Palu-Koro fault. Spectral ratios for horizontal and vertical motion (H/V) from single-station microtremor records were used to identify the predominant periods of the ground vi- brations. Understanding the parameters of predominant period[s] and seismichazard is important for mitigation and environmental planning of the Palu region. Keywords: H/V spectrum, predominant period[s], microtremor single station observation
Ground movement prediction due to block caving mining geometry using GIS Setianto, Agung; Widijanto, Eman
Journal of Applied Geology Vol 3, No 2
Publisher : Geological Engineering Department Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1118.346 KB) | DOI: 10.22146/jag.7185

Abstract

Large scale block cave mining has been operated for over 30 years in the Erstberg Mining District in the province of Papua, Indonesia. The ore body is divided into four vertically stacked ore bodies: Gunung Bijih Timur (GBT), Intermediate Ore Zone (IOZ), Deep Ore Zone (DOZ), and Deep Mill Level Zone (DMLZ). The GBT and IOZ mines were closed on 1993 and 2003, DOZ mine is in its peak production performance 80 ktpd, and DMLZ mine is still in the development stage to prepare mine infrastructures. This situation generates gradual downward settling of the surface or subsidence. Significant deformation changes at the surface by block caving subsidence could damage the mine’s infrastructures in surface and underground and also affect geological structures overlying the mining areas which may result in surface impacts on the natural geomorphology and land use. In this paper, integrated system based on Geographic Information System (GIS) platform applied to predict ground movements due to underground mining. Deep Ore Zone (DOZ) block cave mine is studied for subsidence prediction. The mining extraction thickness model is obtained from height of draw (HOD) observed data. Subsidence Engineering Handbook (SEH) of empirical model and measured data from mining fields is used for subsidence calculation parameters. The calculations were performed in GIS. The maximum vertical displacement has been predicted about 12m by means of full caving mining method. Keywords: Ground movements, block caving, GIS, underground mining, and subsidence
ESTIMATION OF SUBSURFACE STRUCTURE BASED ON MICROTREMOR, BORE HOLE OBSERVATIONS AND STOCHASTIC STRONG GROUND MOTION SIMULATIONS IN PALU CITY, CENTRAL SULAWESI, INDONESIA: A VALIDATION AND SENSITIVITY STUDY ON THE 23 JANUARY 2005 (PALU) EARTHQUAKE Thein, Pyi Soe; Pramumijoyo, Subagyo; Wilopo, Wahyu; Setianto, Agung; Brotopuspito, Kirbani Sri; Kiyono, Junji
Journal of Applied Geology Vol 6, No 2
Publisher : Geological Engineering Department Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jag.7222

Abstract

In this study, we investigated the subsurface structure and strong ground motion parameters for Palu City. One of the major structures in Central Sulawesi is the Palu-Koro Fault system. Several powerful earthquakes have struck along the Palu-Koro Fault during recent years, one of the largest of which was an M 6.3 event that occurred on January 23, 2005 and caused several casualties. Following the event, we conducted a microtremor survey to estimate the shaking intensity distribution during the earthquake. From this survey we produced a map of the peak ground acceleration, velocity and ground shear strain in Palu City. We performed single observations of microtremors at 151 sites in Palu City. The results enabled us to estimate the site-dependent shaking characteristics of earthquake ground motion. We also conducted 8-site microtremor array investigation to gain a representative determination of the soil condition of subsurface structures in Palu. From the dispersion curve of array observations, the central business district of Palu corresponds to relatively soil condition with Vs ≤ 300 m/s, the predominant periods due to horizontal vertical ratios (HVSRs) are in the range of 0.4 to 1.8 s and the resonant frequency are in the range of 0.7 to 3.3 Hz. Three boreholes were throughout the basin especially in Palu area to evaluate the geotechnical properties of subsurface soil layers. The depths are varying from 1 m to 30 m. Strong ground motions of the Palu area were predicted based on the empirical stochastic green’s function method. Peak ground acceleration and peak ground velocity becomes more than 0.04 g and 30 kine in some areas, which causes severe damage for buildings in high probability. Keywords: Palu-Koro fault, microtremor, bore holes, peak ground acceleration and velocity.
COMPARISON OF KRIGING AND INVERSE DISTANCE WEIGHTED (IDW) INTERPOLATION METHODS IN LINEAMENT EXTRACTION AND ANALYSIS Setianto, Agung; Triandini, Tamia
Journal of Applied Geology Vol 5, No 1
Publisher : Geological Engineering Department Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1387.648 KB) | DOI: 10.22146/jag.7204

Abstract

Analysis that is based on geostatistics eliminates many corresponding defects and limitations compared to classical statistics which have been developed by random distribution theory of processes and variables. Interpolation is important for local analysis by GIS, because many maps used for GIS operation are made by interpolation. In this research, two different methods which is Kriging method and Inverse Distance Weighted (IDW) method was examined for developing Digital Elevation Model image. Each method’s advantages and disadvantages were considered. The study are, Kepil, is within Kulon Progo physiographic and stratigraphic area, located in the western part of Yogyakarta city. This area is located close to the Java Island Subduction Zone, hence influence of tectonic plate movement is relatively dominant. Geological structures become a main factor that shapes the recent morphology. This study area also has many settlements and has high weathering and erosion rate. Lineaments are extracted based on Digital Elevation Model to provide assistance in delineating geological structures. The structural geology analysis and an understanding of tectonic phase of the area provide useful information for geological map- ping. Accuracy of lineament depends on extraction and imagery parameters used. In this study, the extraction was conducted by two different raster methods, namely Kriging and Inverse Distance Weighted (IDW) with the same resolution of 30 meters. Lineament extracted automatically (digitally) with certain parameter settings. Keywords: Kriging, inverse distance weighted, interpolation, lineament, random distribution, digital elevation model.
DYNAMIC MORPHOLOGICAL CHANGES OF SPIT IN APRIL–MAY 2014 IN OPAK RIVER MOUTH, BANTUL, DAERAH ISTIMEWA YOGYAKARTA Freski, Yan Restu; Setianto, Agung; Srijono, Srijono
Journal of Applied Geology Vol 6, No 2
Publisher : Geological Engineering Department Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (2475.357 KB) | DOI: 10.22146/jag.7221

Abstract

As an oceanic coast, the beaches in the southern part of Java Island are predominantly influenced by ocean energy which is driven by periodical monsoon. This periodical process impacts the dynamic changes of spit in the river mouth system. Therefore, spit is a key to study the process in the southern coast of Java Island especially in Opak River Mouth. It needs a deep-root explanation about the morphological changes and the sedimentological mechanism. This research project was built by data such as spit geometry, aerial photographs and spontaneous wind direction. The supporting data included multitemporal IKONOS-Quickbird images from Google Earth and aerial photographs. These data were collected from field-work investigation and laboratorywork. The spit geometry was compiled by Global Positioning System handheld tracking along the edge of spit and crosschecked by aerial photograph using pole. The ultimate interpretation and periodic models were built by data reconstruction based on the geometry of spit and spontaneous wind direction. Spit changed weekly due to monsoon transition in April to May 2014. The morphological changes could be noted as the spit starting to be cut off by the highrate flow of Opak River. The process continued until the net drift moving westward. Keywords: April, coast, May, Opak river mouth, spit.
Aplikasi Principle Component Analysis dan Directed Principal Component untuk Pemetaan Alterasi Hidrotermal menggunakan Citra ASTER di Kecamatan Kokap, Kulon Progo Raharja, Bayu; Setianto, Agung; Titisari, Anastasia Dewi
Jurnal Geologi dan Sumberdaya Mineral Vol 20, No 3 (2019): Article in Press
Publisher : Pusat Survei Geologi

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (3979.079 KB) | DOI: 10.33332/jgsm.geologi.20.3.119-131

Abstract

Endapan emas di daerah Kokap, Kabupaten Kulon Progo yang berasosiasi dengan endapan tipe epitermal terbentuk akibat adanya proses alterasi hidrotermal. Pemanfaatan data penginderaan jauh untuk pemetaan alterasi telah berhasil dilakukan diberbagai lokasi. Penelitian ini bertujuan untuk mengkaji kemampuan citra ASTER saluran visible near infrared (VNIR) dan saluran shortwave infrared (SWIR) dalam memetakan jenis alterasi menggunakan metode Principle Component Analysis (PCA) dan Directed Principal Component (DPC). Klasifikasi multispektral selanjutnya dilakukan untuk membedakan tipe alterasi hidrotermal menggunakan kombinasi saluran hasil PCA dan DPC. Keberhasilan pemetaan alterasi hidrotermal dievaluasi secara statistik menggunakan confusion matrix. Tingkat akurasi yang dapat diterima adalah sebesar 85% dengan koefisien kappa lebih besar dari 0.8. Hasil penelitian menunjukkan metode DPC memiliki akurasi lebih baik dari PCA dalam memetakan tipe alterasi meskipun tingkat akurasi keduanya dibawah batas yang ditentukan. Saluran ASTER yang paling baik digunakan untuk memetakan tipe alterasi hidrotermal di lokasi penelitian adalah 1, 2, 4, dan 6.
The Quality and Distribution of Andesite Rock for Construction Materials in Kokap and Temon District, Kulon Progo Regency, Yogyakarta–Indonesia Lenggono, Tego; Eka Putra, Doni Prakasa; Setianto, Agung
Journal of Applied Geology Vol 3, No 2 (2018)
Publisher : Geological Engineering Department Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (10381.49 KB) | DOI: 10.22146/jag.48595

Abstract

The construction projects that are currently being carried out in Kulon Progo Regency, Yogyakarta Special Province, Indonesia, started on 2018, are large-scale projects. The projects include the construction of airports, seaports, industrial estates, southern crossing lanes and the construction of Menoreh lanes. The large-scale projects require a very large supply of andesite rocks for material construction. In Kulon Progo Regency itself, there is a huge potential of andesite rock relate to two geological formations (Kebo Butak and Andesite Intrusion) exist in the region, which is found mostly in Kokap District and partly in Temon District. One parameter that determines the quality of andesite rock is their compressive strength. Due to weathering, not all of the andesite in both formation can be classified as good quality rocks. According to Indonesian Standard, theminimum compressive strength of natural stone for stakes and curbstone is 500 kg/cm2 , for lightweight building foundation is 800 kg/cm2 , for medium building foundations is 1000 kg/cm 2and for heavy building foundations is 1500 kg/cm 2 . Based on this background, this paper have objectives to know the quality of andesite rock exist in the research area and to determine the zonation of good quality andesite rock for building and road materials in the research area. Field observation were conducted to map the occurrence of andesite rock. Totally 68 rock samples were collected during field observation and tested by point load test method to know its compressive strength value. The distribution of good quality rock in the research area were determine based on spatial analysis procedure in geographical information system. Results show that andesite rocks found in research area have a compressive strength ranging from 167.12 kg/cm 2 to 2783.37 kg/cm 2 . From 53 samples taken from igneous rock intrusion, it showed that 7.55 % had low quality, 13.21 % had medium quality, 30.19 % had good quality and 49.06 % had very good quality. From the 16 samples taken from the Kebobutak Formation, it showed that 12.50 % had low quality, 18.75 % had good quality and 67.75 % had very good quality. The final map of rock quality zonation reveals 28.92 % of research area classify as low quality, 2.52 % medium quality, 37.68 % good quality and 30.88 % very good quality. It can be concluded that almost 70 % of andesite in the Kokap and Temon District can be used for the running large scale projects.