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PENERAPAN METODE VERY LOW FREQUENCY ELECTROMAGNET (VLF-EM) UNTUK MENAFSIRKAN BIDANG LONGSORAN, STUDI KASUS DESA JOMBOK, KECAMATAN NGANTANG, KABUPATEN MALANG, JAWA TIMUR Wijayanto, Totok; Santosa, Bagus Jaya; Warnana, Dwa Desa; Candra, Arya Dwi
Jurnal Spektra Vol 16, No 3 (2015): Spektra: Jurnal Fisika dan Aplikasinya
Publisher : Jurnal Spektra

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

AbstrakKelongsoran sering terjadi pada tanah yang memiliki topografi curam. Salah satunya adalah yang terjadi di Desa Jombok, Kecamatan Ngantang, Kabupaten Malang, Jawa Timur. Pada areal seluas satu hektar dijumpai penurunan permukaan tanah (longsor). Daerah longsoran ini diteliti dengan menggunakan salah satu metoda Geofisika, yaitu Very Low Frequency-Electromagnetic (VLF-EM). Data lapangan yang didapatkan dari hasil pengukuran metode VLF-EM biasanya tercampur dengan noise dan outlier. Pada penelitian ini digunakan filter NA-MEMD untuk menghilangkan noise dan outlier. Digunakan Filter Karous-Hjelt untuk menganalisa data secara kualitatif. Sedangkan analisa secara kuantitatif diperoleh dengan melakukan pemodelan inversi menggunakan INV2DVLF. Hasil analisis VLF-EM dengan menggunakan filter NA-MEMD mampu mereduksi noise dan outlier dari data pengukuran. Sedangkan hasil inversi 2D menunjukkan bahwa terdapat zona anomali yang menunjukkan zona lemah atau rawan longsor di area penelitian.Â AbstractLandslide often occurs in a steep topography ground. One of them is happened in the Jombok village, Ngantang, Malang, East Java. Land subsidence (landslides) often occur in this area. The landslide area investigated using one of the Geophysics methods, the Very Low Frequency-Electromagnetic (VLF-EM). The field datas obtained from measurement results of VLF-EM method are usually mixed with noise and outliers. In this research, NA-MEMD filter.is used to eliminate the noise and outliers. Karous-Hjelt (K-Hjelt) filter is udes to qualitative analyze of the data. While quantitative analysis is obtained by performing inversion modeling using INV2DVLF. VLF-EM analysis results using the NA-MEMD filter is able to reduce the noise and outliers of measurement data. While the 2D inversion results indicate that there is an anomalous zone which indicates weak or landslide-prone zones in the study area.Keywords: VLF-EM, NA-MEMD, K-Hjelt filter, INV2DVLF, Landslide.

Seismic Anisotropy Analysis Beneath Sumatra Revealed by Shear-Wave Splitting Candra, Arya Dwi; Santosa, Bagus Jaya; Rachman, Gazali
Indonesian Journal on Geoscience Vol 4, No 3 (2017)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17014/ijog.4.3.169-179

DOI: 10.17014/ijog.4.3.169-179A shear-wave splitting analysis was determined to observe anisotropic structures of an upper mantle layer beneath Sumatra. The data were collected from 35 BMKG stations with the magnitude of more than 6.25 Mw and the epicentre of 85o - 140o. A shear-wave splitting measurement was calculated by using Splitlab based on three methods simultaneously. The result of the shear-wave splitting measurement in the Sumatra Forearc and Fault Zone shows that there are two anisotropic layers. The first layer has a dominant-fast-polarization direction that is parallel with a trench, and has the delay time duration of 0.5 - 0.9 s-. It is presumed that it is caused by a shear-strain as a result of the existences of Mentawai and Sumatra Fault Zones. The second layer has a dominant-fast-polarization direction that is perpendicular to the trench with the delay time duration of about 1.1 - 1.9 s-. It is presumed that it is caused by a movement of a subduction plate on a mantle wedge. The measurement in the backarc shows that there is only one anisotropic layer that is a subduction plate. It is also found that there is a transition of an orientation change on the subduction plate between Sumatra and Java. The change of the polarization direction is probably related to the age difference and the direction velocity of the absolute plate movement (APM) from Sumatra to Java.

Seismic Anisotropy Analysis Beneath Sumatra Revealed by Shear-Wave Splitting Candra, Arya Dwi; Santosa, Bagus Jaya; Rachman, Gazali
Indonesian Journal on Geoscience Vol 4, No 3 (2017)
Publisher : Geological Agency

DOI: 10.17014/ijog.4.3.169-179A shear-wave splitting analysis was determined to observe anisotropic structures of an upper mantle layer beneath Sumatra. The data were collected from 35 BMKG stations with the magnitude of more than 6.25 Mw and the epicentre of 85o - 140o. A shear-wave splitting measurement was calculated by using Splitlab based on three methods simultaneously. The result of the shear-wave splitting measurement in the Sumatra Forearc and Fault Zone shows that there are two anisotropic layers. The first layer has a dominant-fast-polarization direction that is parallel with a trench, and has the delay time duration of 0.5 - 0.9 s-. It is presumed that it is caused by a shear-strain as a result of the existences of Mentawai and Sumatra Fault Zones. The second layer has a dominant-fast-polarization direction that is perpendicular to the trench with the delay time duration of about 1.1 - 1.9 s-. It is presumed that it is caused by a movement of a subduction plate on a mantle wedge. The measurement in the backarc shows that there is only one anisotropic layer that is a subduction plate. It is also found that there is a transition of an orientation change on the subduction plate between Sumatra and Java. The change of the polarization direction is probably related to the age difference and the direction velocity of the absolute plate movement (APM) from Sumatra to Java.

Seismic Anisotropy Analysis Beneath Sumatra Revealed by Shear-Wave Splitting Candra, Arya Dwi; Santosa, Bagus Jaya; Rachman, Gazali
Indonesian Journal on Geoscience Vol 4, No 3 (2017)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17014/ijog.4.3.169-179

DOI: 10.17014/ijog.4.3.169-179A shear-wave splitting analysis was determined to observe anisotropic structures of an upper mantle layer beneath Sumatra. The data were collected from 35 BMKG stations with the magnitude of more than 6.25 Mw and the epicentre of 85o - 140o. A shear-wave splitting measurement was calculated by using Splitlab based on three methods simultaneously. The result of the shear-wave splitting measurement in the Sumatra Forearc and Fault Zone shows that there are two anisotropic layers. The first layer has a dominant-fast-polarization direction that is parallel with a trench, and has the delay time duration of 0.5 - 0.9 s-. It is presumed that it is caused by a shear-strain as a result of the existences of Mentawai and Sumatra Fault Zones. The second layer has a dominant-fast-polarization direction that is perpendicular to the trench with the delay time duration of about 1.1 - 1.9 s-. It is presumed that it is caused by a movement of a subduction plate on a mantle wedge. The measurement in the backarc shows that there is only one anisotropic layer that is a subduction plate. It is also found that there is a transition of an orientation change on the subduction plate between Sumatra and Java. The change of the polarization direction is probably related to the age difference and the direction velocity of the absolute plate movement (APM) from Sumatra to Java.

Seismic Anisotropy Analysis Beneath Sumatra Revealed by Shear-Wave Splitting Arya Dwi Candra; Bagus Jaya Santosa; Gazali Rachman
Indonesian Journal on Geoscience Vol 4, No 3 (2017)
Publisher : Geological Agency

DOI: 10.17014/ijog.4.3.169-179A shear-wave splitting analysis was determined to observe anisotropic structures of an upper mantle layer beneath Sumatra. The data were collected from 35 BMKG stations with the magnitude of more than 6.25 Mw and the epicentre of 85o - 140o. A shear-wave splitting measurement was calculated by using Splitlab based on three methods simultaneously. The result of the shear-wave splitting measurement in the Sumatra Forearc and Fault Zone shows that there are two anisotropic layers. The first layer has a dominant-fast-polarization direction that is parallel with a trench, and has the delay time duration of 0.5 - 0.9 s-. It is presumed that it is caused by a shear-strain as a result of the existences of Mentawai and Sumatra Fault Zones. The second layer has a dominant-fast-polarization direction that is perpendicular to the trench with the delay time duration of about 1.1 - 1.9 s-. It is presumed that it is caused by a movement of a subduction plate on a mantle wedge. The measurement in the backarc shows that there is only one anisotropic layer that is a subduction plate. It is also found that there is a transition of an orientation change on the subduction plate between Sumatra and Java. The change of the polarization direction is probably related to the age difference and the direction velocity of the absolute plate movement (APM) from Sumatra to Java.

INSTALASI UNIT BIOGAS DARI LIMBAH KOTORAN SAPI DENGAN METODE ANAEROB MENGGUNAKAN REAKTOR VOLUME 3300 L puput eka suryani; suluh jatmiko; arya dwi candra
SIMETRIS Vol 12 No 2 (2018): SIMETRIS
Publisher : Sekolah Tinggi Teknologi Ronggolawe Cepu

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Medalem is one of the villages located in Kradenan District, Blora Regency,Central Java. Most of the residents of Kradenan have a livelihood as Farmers, includingresidents of Medalem Village. In addition to farming, residents also conduct cattle and goatbreeding activities, this is due to very supportive natural conditions. Medalem Village,especially Sunggun Hamlet, gets a grant in the form of cattle from the local government tobe managed by each farmer group in Sunggun Hamlet. Until now the number of cowsmanaged by farmer groups has reached 28. Several cows maintained in one places or inresidents in their own homes. There are some disadvantage caused by the amount of cowdung produced by these cows, ranging from unpleasant odors, trees and plants that diefrom piles of cow dung, to the dwindling landfill of cow dung. This research aims toprovide appropriate solutions to overcome these problems. The activities carried out are bybuilding the installation of biogas units in Sunggun Hamlet. This biogas processingtechnique uses a cylinder reactor (floating drum). Some of the results of the activities thathave been carried out are more integrated processing of cow manure, no land wasted toaccumulate cow dung, improved soil and air health quality, availability of new LPGreplacement fuel, availability of organic fertilizer that can be directly applied to crops,availability of waste solid that can be used as a planting medium.

PERBANDINGAN METODE EEMD DAN EMD UNTUK MEREDUKSI NOISE PADA SINYAL SEISMIK Arya Dwi candra; Puput Eka Suryani
Jurnal Ilmiah Teknosains Vol 4, No 1 (2018): JiTek
Publisher : Universitas PGRI Semarang

Pencuplikan atau picking gelombang P merupakan kegiatan dasar yang harus dilakukan oleh para peneliti/seismologist untuk menganalisis sinyal gempa bumi. Picking gelombang P apabila tidak dilakukan dengan teliti, akan mengakibatkan proses analisis sinyal gempa menjadi tidak akurat. Sinyal gempa yang baik adalah sinyal yang bebas dari noise, baik noise instrument maupun noise lapangan. Gelombang gempa bumi merupakan sinyal gelombang tiga komponen yang sangat kompleks, sehingga diperlukan metode filtering yang dapat memfilter tiga komponen secara simultan. Metode Ensemble Empirical Mode Decomposition (EEMD) adalah suatu metode dekomposisi sinyal yang dapat diterapkan untuk mereduksi noise. Kelebihan EEMD adalah mampu mereduksi noise pada frekuensi tinggi dan rendah tanpa mengubah dari karakter sinyal, sehingga karakteristik sinyal tidak hilang.Kata kunci: EMD, EEMD, Noise, Sinyal gempa.

ANALISIS PENGARUH IRADIASI MICROWAVE TERHADAP GUGUS FUNGSIONAL PADA ZEOLITE SINTESIS Puput Eka Suryani; Arya Dwi Candra
Jurnal Ilmiah Teknosains Vol 3, No 2 (2017): JiTek
Publisher : Universitas PGRI Semarang

Zeolit merupakan material multifungsi yang sering digunakan dalam bidang industri sebagai katalis, ion exchange, adsorber, dll. Dewasa ini telah banyak peneliti yang mempelajari dan mengembangkan teknik sintesis zeolit menggunakan energi baru seperti microwave. Iradiasi microwave terbukti lebih efisien jika diterapkan pada proses kimia maupun fisika. Pada penelitian ini akan dipelajari pengaruh penggunaan microwave terhadap sifat zeolit yang dihasilkan yaitu gugus fungsional pada zeolit. Berdasarkan analisa FTIR pada sampel zeolit sintetis dari abu sekam padi menggunakan modifikasi iradiasi microwave, dapat disimpulkan bahwa kenaikan absorbansi terjadi pada sampel-sampel dengan modifikasi. Hal ini terlihat jelas pada beberapa gugus fungsional seperti Si-OH dan Si-O-Al pada panjang gelombang 3450 cm-1 dan 1000,35 cm-1. Sehingga dapat disimpulkan bahwa iradiasi microwave dapat meningkatkan proses reaksi pada preparasi zeolit sintetis.

PERBANDINGAN METODE EEMD DAN EMD UNTUK MEREDUKSI NOISE PADA SINYAL SEISMIK Arya Dwi candra; Puput Eka Suryani
Jurnal Ilmiah Teknosains Vol 6, No 1 (2020): JiTek
Publisher : Universitas PGRI Semarang

Pencuplikan atau picking gelombang P merupakan kegiatan dasar yang harus dilakukan oleh para peneliti/seismologist untuk menganalisis sinyal gempa bumi. Picking gelombang P apabila tidak dilakukan dengan teliti, akan mengakibatkan proses analisis sinyal gempa menjadi tidak akurat. Sinyal gempa yang baik adalah sinyal yang bebas dari noise, baik noise instrument maupun noise lapangan. Gelombang gempa bumi merupakan sinyal gelombang tiga komponen yang sangat kompleks, sehingga diperlukan metode filtering yang dapat memfilter tiga komponen secara simultan. Metode Ensemble Empirical Mode Decomposition (EEMD) adalah suatu metode dekomposisi sinyal yang dapat diterapkan untuk mereduksi noise. Kelebihan EEMD adalah mampu mereduksi noise pada frekuensi tinggi dan rendah tanpa mengubah dari karakter sinyal, sehingga karakteristik sinyal tidak hilang. Kata kunci: EMD, EEMD, Noise, Sinyal gempa.

PENERAPAN METODE VERY LOW FREQUENCY ELECTROMAGNET (VLF-EM) UNTUK MENAFSIRKAN BIDANG LONGSORAN, STUDI KASUS DESA JOMBOK, KECAMATAN NGANTANG, KABUPATEN MALANG, JAWA TIMUR Totok Wijayanto; Bagus Jaya Santosa; Dwa Desa Warnana; Arya Dwi Candra
Spektra: Jurnal Fisika dan Aplikasinya Vol 16 No 3 (2015): SPEKTRA, Volume 16 Nomor 3, Desember 2015
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1006.029 KB)

Abstrak Kelongsoran sering terjadi pada tanah yang memiliki topografi curam. Salah satunya adalah yang terjadi di Desa Jombok, Kecamatan Ngantang, Kabupaten Malang, Jawa Timur. Pada areal seluas satu hektar dijumpai penurunan permukaan tanah (longsor). Daerah longsoran ini diteliti dengan menggunakan salah satu metoda Geofisika, yaitu Very Low Frequency-Electromagnetic (VLF-EM). Data lapangan yang didapatkan dari hasil pengukuran metode VLF-EM biasanya tercampur dengan noise dan outlier. Pada penelitian ini digunakan filter NA-MEMD untuk menghilangkan noise dan outlier. Digunakan Filter Karous-Hjelt untuk menganalisa data secara kualitatif. Sedangkan analisa secara kuantitatif diperoleh dengan melakukan pemodelan inversi menggunakan INV2DVLF. Hasil analisis VLF-EM dengan menggunakan filter NA-MEMD mampu mereduksi noise dan outlier dari data pengukuran. Sedangkan hasil inversi 2D menunjukkan bahwa terdapat zona anomali yang menunjukkan zona lemah atau rawan longsor di area penelitian. Abstract Landslide often occurs in a steep topography ground. One of them is happened in the Jombok village, Ngantang, Malang, East Java. Land subsidence (landslides) often occur in this area. The landslide area investigated using one of the Geophysics methods, the Very Low Frequency-Electromagnetic (VLF-EM). The field datas obtained from measurement results of VLF-EM method are usually mixed with noise and outliers. In this research, NA-MEMD filter.is used to eliminate the noise and outliers. Karous-Hjelt (K-Hjelt) filter is udes to qualitative analyze of the data. While quantitative analysis is obtained by performing inversion modeling using INV2DVLF. VLF-EM analysis results using the NA-MEMD filter is able to reduce the noise and outliers of measurement data. While the 2D inversion results indicate that there is an anomalous zone which indicates weak or landslide-prone zones in the study area. Keywords: VLF-EM, NA-MEMD, K-Hjelt filter, INV2DVLF, Landslide.

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