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All Journal HAYATI Journal of Biosciences IJOG : Indonesian Journal on Geoscience Jurnal RISET Geologi dan Pertambangan Journal of Degraded and Mining Lands Management Indonesian Journal of Geospatial Eksplorium : Buletin Pusat Pengembangan Bahan Galian Nuklir Jurnal Chemurgy Jurnal Penginderaan Jauh dan Pengolahan Data Citra Digital International Journal of Remote Sensing and Earth Sciences (IJReSES) Jurnal Geologi dan Sumberdaya Mineral (Journal of Geology and Mineral Resources) Bulletin of Geology
Asep Saepuloh
Fakulta Ilmu Dan Teknologi Kebumian, Institut Teknologi Bandung
Agriculture, Biological Sciences & Forestry Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Computer Science & IT Control & Systems Engineering Earth & Planetary Sciences Energy Engineering Environmental Science Social Sciences

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Satellite Imagery for Classification of Rice Growth Phase Using Freeman Decomposition in Indramayu, West Java, Indonesia Rian Nurtyawan; Asep Saepuloh; Agung Budi Harto; Ketut Wikantika; Akihiko Kondoh
HAYATI Journal of Biosciences Vol. 25 No. 3 (2018): July 2018
Publisher : Bogor Agricultural University, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (2686.101 KB) | DOI: 10.4308/hjb.25.3.126

Abstract

  Monitoring at every growth of rice plants is an important information for determining the grain pro-duction estimation of rice. Monitoring must to be have timely work on the rice plant development. However, timely monitoring and the high accuracy of information is a challenge in remote sensing based on rice agriculture monitoring and observation. With increased quality of synthetic aperture radar (SAR) systems utilizing polarimetric information recently, the development and applications of polarimetric SAR (PolSAR) are one of the current major topics in radar remote sensing. The ad-vantages provided by PolSAR data for agricultural monitoring have been extensively studied for applications such as crop type classification and mapping, crop phenology monitoring, productivity assessment based on the sensitivity of polarimetric parameters to indicators of crop conditions. Freeman and Durden successfully decomposed fully PolSAR data into three components: Single bounce, double bounce, and volume scattering. The three-component scattering provide features for distinguishing between different surface cover types. These sensitivities assist in the identification of growing phase. The observed growing phase development in time series, reflected in the consistent temporal trends in scattering, was generally in agreement with crop phenological development stages. Supervised classification was performed on repeat-pass Radarsat-2 images, with an overall classification accuracy of 77.27% achieved using time series Fine beam data. The study demonstrated that Radarsat-2 Fine mode data provide useful information for crop monitoring and classification of rice plants.
PEMETAAN PERMEABILITAS MAGNETIK PERMUKAAN BERBASIS CITRA SAR POLARIMETRIK DENGAN PENGUKURAN IN SITU DI LAPANGAN GUNUNG API Asep Saepuloh; Edo Kharisma Army; Zaki Hilman
JURNAL RISET GEOLOGI DAN PERTAMBANGAN Vol 30, No 2 (2020)
Publisher : Indonesian Institute of Sciences

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/risetgeotam2020.v30.1080

Abstract

Pemetaan parameter fisis berupa permeabilitas magnetik permukaan pada zona lemah yang terkait dengan aktivitas tektonik maupun vulkanik perlu dilakukan seiring dengan meningkatnya aktivitas kegempaan maupun kegunungapian dalam beberapa tahun terakhir. Pendeteksian keberadaan zona lemah umumnya dilakukan berdasarkan parameter kelurusan struktur geologi, reflektansi spektra, dan temperatur permukaan dengan memanfaatkan citra satelit optis. Makalah ini mengolah parameter yang berbeda berupa permeabilitas magnetik permukaan (μr), yaitu parameter fisis yang diturunkan dari citra satelit Polarimetric Synthetic Aperture Radar (PolSAR) dengan polarisasi penuh (quad-polarization) dan diverifikasi dengan pengukuran in situ. Parameter μr permukaan merupakan salah satu parameter yang digunakan untuk mengidentifikasi keberadaan zona lemah jalur fluida termal dari bawah sampai ke permukaan gunung api aktif. Aktivitas hidrotermal mengakibatkan degradasi nilai magnetik batuan di sekitarnya, sehingga ekstraksi nilai permeabilitas magnetik permukaan μr dianggap sangat efektif untuk mengidentifikasi jalur fluida termal di permukaan. Modifikasi pada metode dielectric from Polarimetric Synthetic Aperture Radar (dPSAR) menggunakan citra PolSAR dilakukan untuk mendapatkan parameter permeabilitas magnetik permukaan μr, yaitu kemampuan permukaan tanah dalam menerima respon medan magnet, disamping permitivitas dielektrik εr. Pengukuran μr in situ di lapangan menggunakan alat ukur Ferromaster Magnetic Permeability Meter dilakukan untuk menganalisis tingkat akurasi μr dari hasil inversi dPSAR. Berdasarkan uji validasi, nilai koefisien determinasi R2 yang diperoleh cukup tinggi, yaitu sekitar 0,73 antara μr hasil dPSAR dan pengukuran lapangan. Selain itu, hasil uji normalitas menunjukkan nilai residual antara keduanya terdistribusi normal. Hal ini mengindikasikan bahwa pendeteksian μr dengan metode dPSAR memiliki potensi untuk dikembangkan dan diaplikasikan lebih lanjut dalam pemetaan fisis geologi di permukaan. ABSTRACT - Surface Magnetic Permeability Mapping Using Sar Polarimetric and In Situ Measurement at Volcanic Field. Physical parameters mapping of surface magnetic permeability in weak zones associated with tectonic and volcanic activity is necessary due to the increasing seismic and volcanic activity in recent years. Typically, weak zones are detected from lineament related geological structures, reflectance spectra, and surface temperature visually on optical satellite images. This paper processed a different physical parameter of surface magnetic permeability (μr) derived from the Polarimetric Synthetic Aperture Radar (PolSAR) quad-polarization satellite image that was verified by field measurement. The μr was used to identify the weak zones connected to the fluid path of the subsurface hydrothermal system of an active volcano. The activity of hydrothermal fluids through the weak zones is responsible for the degradation of the magnetic permeability of the host rocks so that extracting μr is effective in identifying fluid path at the surface. A modification has been applied to the dielectric from Polarimetric Synthetic Aperture Radar (dPSAR) method using the PolSAR image by inverting the μr, in addition to εr parameters, that served as capability of the ground surface responds to the magnetic field. Measurement of μr in the field using Ferromaster Magnetic Permeability Meter was carried out to analyze the accuracy of the inverted μr from the dPSAR method. According to the validation test of μr that derived from dPSAR and field measurement, a high coefficient determination R2 of 0.73 was achieved. In addition, the normality test showed that residual values were distributed normally. Therefore, the μr inversion using dPSAR method has the potential to be developed and applied for advanced physical surface geological mapping.
Analisis Perubahan Topografi Gunung Sinabung dan Gunung Sibayak Menggunakan Citra Satelit ALOS PALSAR Mila Olivia Trianaputri; Asep Saepuloh; Ketut Wikantika
Indonesian Journal of Geospatial Vol 6 No 1 (2017)
Publisher : Indonesian Journal of Geospatial

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

Abstract

Pulau Ring of fire merupakan julukan yang diberikan kepada Indonesia, atas keberadaan deretan gunung api  diwilayahnya. Posisi tersebut membuat Indonesia wajib memiliki informasi dan pengetahuan yang luas mengenai hal-hal yang berkaitan dengan gunung api, termasuk mengenai kebencanaan yang mungkin terjadi sebagai akibat dari kondisi wilayah tersebut. Gunung api Sinabung yang terdapat di Kabupaten Karo, Sumatera Utara, merupakan salah satu contoh gunung api di Indonesia yang terus mengalami peningkatan aktivitas vulkanik semenjak tahun 2010. Penelitian ini bertujuan untuk mendapatkan grafik perubahan topografi yang terjadi di puncak Gunung Sinabung dan Sibayak, serta mengetahui waktu mulai terjadinya perubahan topografi yang akan mengindikasikan adanya precursor behavior sebelum letusan terjadi. Teknologi penginderaan jauh membuat keseluruhan proses pengamatan topografi tersebut menjadi lebih cepat dan dapat menghemat biaya survei geologi. Metode yang dilakukan adalah dengan mengekstraksi nilai intensitas hamburan balik yang direkam dalam setiap piksel citra SAR Gunung Sinabung dan Gunung Sibayak, kemudian menghitung nilai normalised radar cross section dari hasil ekstraksi tersebut. Selanjutnya untuk validasi data, dibuat citra rasio yang merupakan perbandingan antara citra sebelum terjadinya letusan dan citra sesudah terjadinya letusan untuk identifikasi arah penyebaran volcanic product Gunung Sinabung. Dengan metode tersebut maka akan dihasilkan informasi mengenai perubahan topografi dan precursor behavior yang ditunjukkan oleh Gunung Sinabung.
Advanced Applications of Synthetic Aperture Radar (SAR) Remote Sensing for Detecting Pre- and Syn-eruption Signatures at Mount Sinabung, North Sumatra, Indonesia Asep Saepuloh; Prima Rizky Mirelva; Ketut Wikantika
Indonesian Journal on Geoscience Vol 6, No 2 (2019)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (15.695 KB) | DOI: 10.17014/ijog.6.2.123-140

Abstract

DOI:10.17014/ijog.6.2.123-140Mount Sinabung was re-activated at August 28th, 2010 after a long repose interval. The early stage of a phreatic eruption was then followed by magmatic eruptions at September 15th, 2013 for years until now. To understand the ground surface changes accompanying the eruption periods, comprehensive analyses of surface and subsurface data are necessary, especially the condition in pre- and syn-eruption periods. This study is raised to identify ground surface and topographical changes before, intra, and after the eruption periods by analyzing the temporal signature of surface roughness, moisture, and deformation derived from Synthetic Aperture Radar (SAR) data. The time series of SAR backscattering intensity were analyzed prior to and after the early eruption periods to know the lateral ground surface changes including estimated lava dome roughness and surface moisture. Meanwhile, the atmospherically corrected Differential Interferometric SAR (D-InSAR) method was also applied to know the vertical topographical changes prior to the eruptions. The atmospheric correction based on modified Referenced Linear Correlation (mRLC) was applied to each D-InSAR pair to exclude the atmospheric phase delay from the deformation signal. The changes of surface moistures on syn-eruptions were estimated by calculating dielectric constant from SAR polarimetric mode following Dubois model. Twenty-one Phased Array type L-band SAR (PALSAR) data on board Advanced Land Observing Satellite (ALOS) and nine Sentinel-1A SAR data were used in this study with the acquisition date between February 2006 and February 2017. For D-InSAR purposes, the ALOS PALSAR data were paired to generate twenty interferograms. Based on the D-InSAR deformation, three times inflation-deflation periods were observed prior to the early eruption at August 28th 2010. The first and second inflation-deflation periods at the end of 2008 and middle 2009 presented migration of magma batches and dike generations in the deep reservoir. The third inflation-deflation periods in the middle of 2010 served as a precursor signal presenting magma feeding to the shallow reservoir. The summit was inflated about 1.4 cm and followed by the eruptions. The deflation of about 2.3 cm indicated the release pressure and temperature in the shallow reservoir after the early eruption at August 28th, 2010. The last inflation-deflation period was also confirmed by the increase of the lava dome roughness size from 5,121 m2 on July to 6,584 m2 on August. The summit then inflated again about 1.1 cm after the first eruption and followed by unrest periods presented by lava dome growth and destruction at September 15th, 2013. The volcanic products including lava and pyroclastics strongly affected the moisture of surface layer. The volcanic products were observed to reduce the surface moisture within syn-eruption periods. The hot materials are presumed responsible for the evaporation of the surface moisture as well.
Interpretasi Vulkanostratigrafi Daerah Mamuju Berdasarkan Analisis Citra Landsat-8 Frederikus Dian Indrastomo; I Gde Sukadana; Asep Saepuloh; Agus Handoyo Harsolumakso; Dhatu Kamajati
EKSPLORIUM Vol 36, No 2 (2015): November 2015
Publisher : Pusat Teknologi Bahan Galian Nuklir - BATAN

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1482.403 KB) | DOI: 10.17146/eksplorium.2015.36.2.2772

Abstract

Daerah Mamuju dan sekitarnya umumnya disusun oleh batuan gunung api. Batuan sedimen vulkanoklastik dan batugamping berada di atas batuan gunung api. Aktivitas gunung api membentuk beberapa morfologi unik seperti kawah, kubah lava, dan jalur hembusan piroklastika sebagai produknya. Produk tersebut diidentifikasi berdasarkan karakter bentuk-bentuk melingkar di citra Landsat-8. Hasil koreksi geometrik dan atmosferik, interpretasi visual pada citra Landsat-8 dilakukan untuk mengidentifikasi struktur, geomorfologi, dan kondisi geologi daerah tersebut. Struktur geologi regional menunjukkan kecenderungan arah tenggara – baratlaut yang mempengaruhi pembentukan gunung api Adang. Geomorfologi daerah tersebut diklasifikasikan menjadi 16 satuan geomorfologi berdasarkan aspek genetisnya, yaitu punggungan blok sesar Sumare, punggungan kuesta Mamuju, kawah erupsi Adang, kawah erupsi Labuhan Ranau, kawah erupsi Sumare, kerucut gunung api Ampalas, kubah lava Adang, bukit intrusi Labuhan Ranau, punggungan aliran piroklastik Adang, punggungan aliran piroklastik Sumare, perbukitan sisa gunung api Adang, perbukitan sisa gunung api Malunda, perbukitan sisa gunung api Talaya, perbukitan karst Tapalang, dan dataran aluvial Mamuju, dataran teras terumbu Karampuang. Berdasarkan hasil interpretasi citra Landsat-8 dan konfirmasi lapangan, geologi daerah Mamuju dibagi menjadi batuan gunung api dan batuan sedimen. Batuan gunung api terbagi menjadi dua kelompok, yaitu Kompleks Talaya dan Kompleks Mamuju. Kompleks Talaya terdiri atas batuan gunung api Mambi, Malunda, dan Kalukku berkomposisi andesit, sementara Kompleks Mamuju terdiri atas batuan gunung api Botteng, Ahu, Tapalang, Adang, Ampalas, Sumare, dan Labuhan Ranau berkomposisi andesit sampai basal leusit. Vulkanostratigrafi daerah ini disusun berdasarkan analisis struktur, geomorfologi, dan distribusi litologi. Vulkanostratigrafi daerah Mamuju diklasifikasikan ke dalam Khuluk Talaya dan Khuluk Adang. Khuluk Talaya terdiri atas Gumuk Mambi, Gumuk Malunda, dan Gumuk Kalukku. Khuluk Mamuju terdiri atas Gumuk Botteng, Gumuk Ahu, Gumuk Tapalang, Gumuk Adang, Gumuk Ampalas, Gumuk Sumare, dan Gumuk Labuhan Ranau. Mamuju and its surrounding area are constructed mainly by volcanic rocks. Volcanoclastic sedimentary rocks and limestones are laid above the volcanic rocks. Volcanic activities create some unique morphologies such as craters, lava domes, and pyroclastic flow paths as their volcanic products. These products are identified from their circular features characters on Landsat-8 imagery. After geometric and atmospheric corrections had been done, a visual interpretation on Landsat-8 imagery was conducted to identify structure, geomorphology, and geological condition of the area. Regional geological structures show trend to southeast – northwest direction which is affects the formation of Adang volcano. Geomorphology of the area are classified into 16 geomorphology units based on their genetic aspects, i.e Sumare fault block ridge, Mamuju cuesta ridge, Adang eruption crater, Labuhan Ranau eruption crater, Sumare eruption crater, Ampalas volcanic cone, Adang lava dome, Labuhan Ranau intrusion hill, Adang pyroclastic flow ridge, Sumare pyroclastic flow ridge, Adang volcanic remnant hills, Malunda volcanic remnant hills, Talaya volcanic remnant hills, Tapalang karst hills, Mamuju alluvium plains, and Karampuang reef terrace plains. Based on the Landsat-8 imagery interpretation result and field confirmation, the geology of Mamuju area is divided into volcanic rocks and sedimentary rocks. There are two groups of volcanic rocks; Talaya complex and Mamuju complex. The Talaya complex consists of Mambi, Malunda, and Kalukku volcanic rocks with andesitic composition, while Mamuju complex consist of Botteng, Ahu, Tapalang, Adang, Ampalas, Sumare, danLabuhanRanau volcanic rocks with andesite to leucitic basalt composition. The volcanostratigraphy of Mamuju area was constructed based on its structure, geomorphology and lithology distribution analysis. Volcanostratigraphy of Mamuju area is classified into Khuluk Talaya and Khuluk Mamuju. The Khuluk Talaya consists of Gumuk Mambi, Gumuk Malunda, and Gumuk Kalukku, while Khuluk Mamuju consists of Gumuk Botteng, Gumuk Ahu, Gumuk Tapalang, Gumuk Adang, Gumuk Ampalas, Gumuk Sumare, and Gumuk Labuhan Ranau.
IDENTIFIKASI POTENSI REMBESAN MIKRO DI LAPANGAN MIGAS MELALUI DETEKSI MINERAL LEMPUNG MENGGUNAKAN CITRA LANDSAT 8 OLI/TIRS, STUDI KASUS LAPANGAN MIGAS CEKUNGAN JAWA BARAT BAGIAN UTARA Tri Muji Susantoro; Ketut Wikantika; Asep Saepuloh; Agus Handoyo Harsolumakso
Jurnal Penginderaan Jauh dan Pengolahan Data Citra Digital Vol. 15 No. 1 Juni 2018
Publisher : Indonesian National Institute of Aeronautics and Space (LAPAN)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (805.415 KB) | DOI: 10.30536/j.pjpdcd.2018.v15.a2779

Abstract

Clay minerals in the oil and gas field have changed with an increase of the quantities in the middle of the oil and gas field and reduction in the edges. This reduction is the effect of micro seepage from oil and gas from the subsurface. The aims of the research is to identify the potential oil and gas seepage through clay mineral mapping. The data used where Landsat 8 OLI/TIRS with recording dated September 25, 2015. The method used in the mapping of clay minerals using the ratio of 1.55-1.75 µm (Short Wave Infrared 1) and 2.08-2.35 µm (Short Wave Infrared 2). The result of Landsat 8 OLI/TIRS data processing shows the potential of anomalies in edges of the oil and gas field. The anomaly is a change in the index value of clay minerals that tend to be lower with values 1.0 to 1.5 than the middle of oil and gas field with values 1.5 to 2.0. The potential pattern of the anomaly follows the border of the oil and gas field. Field surveys show that oil and gas field based on grain size analysis is dominated by clay-sized soil. The dominant clay minerals from X-Ray Diffraction analysis are smectite (56%) and kaolinite (6%).ABSTRAKMineral lempung di lapangan migas mengalami perubahan dengan terjadinya peningkatan kandungannya pada tengah lapangan migas dan pengurangan di tepinya. Pengurangan ini merupakan efek adanya rembesan mikro dari migas yang berasal dari bawah permukaan. Kajian ini bertujuan untuk mengidentifikasi adanya potensi rembesan migas melalui pemetaan mineral lempung. Adapun data yang digunakan adalah Landsat 8 OLI/TIRS dengan perekaman tanggal 25 September 2015. Metode yang digunakan pada pemetaan mineral lempung menggunakan perbandingan panjang gelombang 1.55-1.75 µm (Short Wave Infrared 1) dengan 2.08-2.35 µm (Short Wave Infrared 2). Hasil pengolahan data Landsat 8 OLI/TIRS menunjukkan adanya potensi anomali di tepi lapangan migas. Anomali tersebut berupa perubahan nilai indeks mineral lempung yang cenderung lebih rendah yaitu dengan nilai 1,0 – 1,5 dibandingkan lokasi di tengah lapangan yaitu dengan nilai 1,5 – 2,0.  Pola potensi anomali tersebut mengikuti batas tepi lapangan migas. Survei lapangan menunjukkan bahwa pada lapangan migas berdasarkan analisis ukuran butir didominasi oleh tanah berukuran lempung. Adapun mineral lempung yang dominan dari hasil analisis XRD berupa smektit (56%) dan terdapat kaolinit (6%).
Integration of remote sensing and geophysical data to enhance lithological mapping utilizing the Random Forest classifier: a case study from Komopa, Papua Province, Indonesia Hary Nugroho; Ketut Wikantika; Satria Bijaksana; Asep Saepuloh
Journal of Degraded and Mining Lands Management Vol 10, No 3 (2023)
Publisher : Brawijaya University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15243/jdmlm.2023.103.4417

Abstract

Lithological information is important in mineral resource exploration, geological observations, mine planning or degradation vulnerability assessment. Currently, lithology mapping can be performed in a fast, inexpensive, and easy way using remote sensing data and machine learning. Remote sensing techniques have become a valuable and promising tool for mapping lithological units and searching for minerals. Typically, the integration of remote sensing data with geophysical data provides a better diagnosis to lithological units than single-source mapping methodologies. Accordingly, this study used a combination of remote sensing and airborne geophysical data utilizing the Random Forest algorithm with small training samples to enhance lithology mapping in Komopa, Papua Province, Indonesia. Geophysical data consisting of magnetic, electromagnetic, and radiometric were added one by one gradually to the remote sensing data, which includes Sentinel 2A, ALOS PALSAR, and DEM (digital elevation model) to compare the accuracy of the classification results from each dataset. The results showed that the model that combined remote sensing data and the three types of geophysical data produced the best classification, with an overall accuracy of 0.81, precision of 0.66, recall of 0.47, and F1 score of 0.52. This fused data can increase the accuracy of the classification results by 8% overall accuracy, 6% precision, 11% recall, and 13% F1 score when compared to the model that only used remote sensing data.
APPLICATION OF LAND SURFACE TEMPERATURE DERIVED FROM ASTER TIR TO IDENTIFY VOLCANIC GAS EMISSION AROUND BANDUNG BASIN Hilman, Zaki; Saepuloh, Asep; Susanto, Very
International Journal of Remote Sensing and Earth Sciences (IJReSES) Vol 16, No 2 (2019)
Publisher : National Institute of Aeronautics and Space of Indonesia (LAPAN)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (657.454 KB) | DOI: 10.30536/j.ijreses.2019.v16.a3254

Abstract

Gas emission in volcanic areas is one of the features that can be used for geothermal exploration and to monitor volcanic activity. Volcanic gases are usually emitted in permeable zones in geothermal fields. The use of thermal infrared radiometers (TIR) onboard of advanced spaceborne thermal emission and reflection radiometers (ASTER) aims to detect thermal anomalies at the ground surface related to gas emissions from permeable zones. The study area is located around Bandung Basin, West Java (Indonesia), particularly the Papandayan and Domas craters. This area was chosen because of the easily detected land surface temperature (LST) following emissivity and vegetation corrections (Tcveg). The ASTER TIR images used in this study were acquired by direct night and day observation, including observations made using visible to near-infrared radiometers (VNIR). Field measurements of volcanic gases composed of SO2 and CO2 were performed at three different zones for each of the craters. The measured SO2 concentration was found to be constant over time, but CO2 concentration showed some variation in the craters. We obtained results suggesting that SO2 gas measurements and Tcveg are highly correlated. At Papandayan crater, the SO2 gas concentration was 334.34 ppm and the Tcveg temperature was 35.67 °C,  results that are considered highly anomalous. The same correlation was also found at Domas crater, which showed an increased SO2 gas concentration of 35.39 ppm located at a high-anomaly Tcveg of 30.65 °C. Therefore, the ASTER TIR images have potential to identify volcanic gases as related to high Tcveg.
Pemetaan Geologi Gunung Api Dijital Daerah Ngebel, Madiun berdasarkan Data Reflektansi dan Suseptibilitas Magnetik Batuan Asep Saepuloh; Raditya Andrean Saputra; Prihadi Sumintadireja
Jurnal Geologi dan Sumberdaya Mineral Vol. 18 No. 4 (2017): Jurnal Geologi dan Sumberdaya Mineral
Publisher : Pusat Survei Geologi

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33332/jgsm.geologi.v18i4.338

Abstract

This study was taken as a part of volcano geology mapping at Ngebel area including volcanostratigraphy and structural geology interpretations by optimizing the satellite remote sensing and terestrial data. Ngebel area is located at the western flank of Mt. Wilis volcanic complex, Madiun District, East Java, Indonesia. The purpose of this study is to obtain the effectiveness of atmospherically corrected satellite image of Landsat-8 OLI (Operational Land Imager) TIRS (Thermal Infrared Sensor) and rock magnetic susceptibility for identifying volcanic products. The Landsat-8 OLI/TIRS image processing is performed in two steps: pre and post field observation. The pre field observation step was treated by processing and analysing the Landsat-8 OLI/TIRS to produce geomorphological units, circular/linear feature, rock unit boundary, and interpreted eruption center by examining image color, tone, and texture. Furthermore, the reflectance spectra analyses of Landsat-8 OLI/TIRS were obtained to define detailed volcanic product unit boundary after the field observation performed. Magnetic susceptibility of the rocks was used to classify the volcanostratigraphic units based on their magnetization degree of the induced rocks. Considering the  magnetic susceptibility, there are suggested two groups of volcanic unit or Hummocks (Gumuk): Hummock of Ngebel with low susceptibility (9.9×10-3 – 20.7×10-3) and Hummock of Manyutan with medium (20.7×10-3 – 48.7×10-3) to high susceptibility (≥48.7×10-3). Noticing the reflectance spectra of Landsat-8 OLI/TIRS, it can be defined five volcanic rock units: pyroclastic fall Ngebel (reflectance value at  0.63 – 0.71), pyroclastic flows Ngebel (reflectance value at 0.71 – 0.74),  pyroclastic flow Manyutan (reflectance value at 0.74 – 0.78), lava Manyutan 1 (reflectance value at 0.78 – 0,84), and Lava Manyutan 2 (reflectance value at  ≥0.84).Keyword: Volcanostratigraphy, Landsat-8 OLI/TIRS, magnetic susceptibility, reflectance, Ngebel
Characterizing SO2 Emission Rate, Thermal Anomalies, from Opened and Closed Vent System at Agung, Bromo, and Sinabung Volcanoes in Indonesia Hilma Alfianti; Asep Saepuloh; Mamay Surmayadi; Syegi L. Kunrat; Ugan B. Saing; I.G.B. Eddy Sucipta; Sofyan Primulyana
Indonesian Journal on Geoscience Vol. 10 No. 2 (2023)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17014/ijog.10.2.277-295

Abstract

Agung, Bromo, and Sinabung Volcanoes have high volcanic activity over the last decade, and have different eruption characteristics. Hence, it would be fascinating to study the characteristics of their volcanic activity patterns based on SO2 emission rates and thermal anomaly correlated with the seismicity data. The SO2 emission rate measurement was carried out using the Differential Optical Absorption Spectroscopy (DOAS), and calculated based on SO 2 column density, distance of measurement, wind speed, and wind direction. In addition, SO2 emission was detected using Ozone Monitoring Instrument (OMI) images with daily global coverage. Thermal anomaly detection was performed using Advance Spaceborne Thermal Emission and Reflection Radiometer (ASTER) of Thermal Infrared (TIR) subsystem with high spatial resolution (90x90 m). ASTER TIR images were corrected for radiometric and thermal atmospheric. The emissivity and brightness temperature separation algorithm was applied to obtain surface temperature of Agung, Bromo, and Sinabung Volcanoes. All the data were correlated with the seismicity of each volcano. The SO2 emission rates correlate with the magma ascent to the shallow depth in an open system volcano (Bromo Volcano). In the closed-system volcanoes (early phase of Agung and Sinabung), SO2 emission was detected after the transition of closed to open system. Magmatic injection from the reservoir to the shallow depth was detected as thermal anomalies, such as in Agung Volcano. Whereas in Bromo Volcano, the thermal anomaly was insignificant since Bromo Volcano has an explosive eruption at a short period, so the ASTER image could not observe the thermal anomaly on the eruption time. Thermal anomaly pattern in Sinabung Volcano was the manifestation of new magmatic injection to the shallow depth. Therefore, their increase serves as indicators for the increasing magmatic activity prior to the eruptions. Keywords: SO2 emission rate, thermal anomaly, DOAS, OMI, ASTER, Open Vent, Closed Vent
Co-Authors Agung Budi Harto Agung Budi Harto Agus Handoyo Harsolumakso Agus Handoyo Harsolumakso Akihiko Kondoh Dhatu Kamajati Edo Kharisma Army Frederikus Dian Indrastomo Habibah, Miftah Faaza Hary Nugroho Hilma Alfianti Hilman, Zaki I Gde Sukadana I.G.B. Eddy Sucipta Ketut Wikantika Lazuardy Fajar Pratama Sulaeman Mamay Surmayadi Mila Olivia Trianaputri Mirelva, Prima Rizky Panggea Ghiyats Sabrian Permana Adhitya Lano Prihadi Sumintadireja Raditya Andrean Saputra Resty Intan Putri Rian Nurtyawan Satria Bijaksana Shoedarto, Riostantieka Mayandari Sofyan Primulyana Susanto, Very Syegi L. Kunrat Tahjudil Witra Tri Muji Susantoro Ugan B. Saing Zaki Hilman