Putri, Megawati Sunarno (2020) Aplikasi Filter NA-MEMD pada Data VLF-EM untuk Mengidentifikasi Kemenerusan Sungai Bawah Permukaan (Studi Kasus Desa Sekar, Pacitan). Other thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Kawasan karst Desa Sekar, Pacitan memiliki gua-gua yang terhubung akibat adanya sistem rekahan yang berkembang. Terbentuknya sistem rekahan ini dikarenakan adanya proses pelarutan yang tinggi pada lapisan batuan sehingga terbentuk rekahan gua, seperti Luweng Kuniran, Luweng Musuk dan Luweng Dawung. Rekahan gua yang dialiri air kemudian terakumulasi dan membentuk sungai bawah permukaan. Kompleksitas daerah karst membutuhkan metode geofisika khusus untuk mengidentifikaasi sungai bawah permukaan, seperti metode VLF-EM. Metode ini termasuk metode yang ramah lingkungan dengan mobilitas alat yang mudah serta penetrasi kedalaman yang relatif dalam. Filter NA-MEMD berguna dalam data VLF-EM ini, karena dapat mereduksi noise yang terkandung dengan cara memisahkan dan merekonstruksi ulang data secara simultan. Pengambilan data terdiri dari 3 lintasan pengukuran dengan panjang lintasan masing-masing 350 m, 900 m, dan 550 m serta jarak antar titik 10 m. Data yang diperoleh dari hasil pengukuran berupa tilt dan elliptisitas. Sungai bawah permukaan dapat diidentifikasi melalui interpretasi kualitatif (filter Fraser dan filter Karous-HJelt). Kemenerusan sungai bawah permukaan teridentifikasi pada tiap lintasan pengukuran dan berkorelasi dengan manifestasi yang ada. Arah kemenerusan sungai bawah permukaan ini berada pada azimuth N45⁰E- N65⁰E.
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The karst area of Sekar Village, Pacitan has connected caves due to a developing fracture system. The formation of this fracture system is due to the high dissolution process in the rock layers so that the cave fractures are formed, such as Luweng Kuniran, Luweng Musuk and Luweng Dawung. The fracture of the cave which was drained by water then accumulated and formed an underground rivers. The complexity of karst areas requires a special geophysical method to identify underground rivers, the VLF-EM method. This method includes an environmentally friendly method with easy tool mobility and relatively deep penetration depth. NA-MEMD filter is useful in this VLF-EM data, because it can reduce the noise contained by separating and reconstructing data simultaneously. The data collection consisted of 3 measurement lines with a length of 350 m, 900 m and 550 m each, and a distance between points of 10 m. The data obtained from the measurement results are in the form of tilt and ellipticity. Underground rivers can be identified through qualitative interpretations (Fraser filters and Karous-HJelt filters). The continuity of underground rivers is identified at each measurement path and correlates with existing manifestations. The direction of underground river continuity is in the azimuth N45⁰E-N65⁰E.
| Item Type: | Thesis (Other) |
|---|---|
| Uncontrolled Keywords: | karst, NA-MEMD, sungai bawah permukaan, VLF-EM karst, NA-MEMD, underground river, VLF-EM |
| Subjects: | G Geography. Anthropology. Recreation > GB Physical geography > GB600 Karst conservation. |
| Divisions: | Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Geophysics Engineering > 33201-(S1) Undergraduate Thesis |
| Depositing User: | Megawati Sunarno Putri |
| Date Deposited: | 11 Aug 2020 06:51 |
| Last Modified: | 30 May 2023 07:35 |
| URI: | http://repository.its.ac.id/id/eprint/77468 |
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