Iswari, Hafsyah (2019) Identifikasi Endapan Piroklastik Pada Kaldera Lama dengan Menggunakan Metode Geolistrik Resistivitas (Studi Kasus : Kecamatan Sembalun, Kabupaten Lombok Timur). Other thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Gunung Rinjani merupakan salah satu gunungapi aktif yang terletak di Provinsi Nusa Tenggara Barat dengan morfologi kaldera yang membentang luas di tengahnya. Sejarah mencatat selama kurun 800 tahun terakhir terjadi 12 kali erupsi vulkanik di tengah kaldera Gunung Rinjani. Periode erupsi vulkanik terbagi menjadi tiga periode, yaitu sebelum pembentukan kaldera (pra kaldera), masa pembentukan kaldera, dan sesudah pembentukan kaldera. Material berupa batuan piroklastik hadir dalam setiap erupsi vulkanik, sehingga dapat diidentifikasi proses geologi yang terjadi dengan dilakukan pengukuran geofisika menggunakan metode geolistrik resistivitas yang selanjutnya dapat diketahui formasi batuan penyusun bawah permukaan menggunakan software EarthImager 2D. Pengukuran geolistrik menggunakan sistem multichannel konfigurasi Dipole-Dipole dengan panjang lintasan 2200 meter dengan jarak antar elektroda 10 meter. Dari hasil pemodelan 2D memiliki rentang nilai resistivitas 1,5 Ωm - 5,5 Ωm diduga tersusun atas lapisan air tanah yang berisi batuan lempung, 20,9 Ωm diduga tersusun atas batuan tuf, dan rentang nilai resistivitas 54 Ωm - 300 Ωm diduga tersusun atas batuan lava breksi dan diduga sebagai daerah persebaran endapan piroklastik. Oleh karena itu persebaran endapan piroklastik terbentang luas sepanjang satu lintasan dengan ketebalan rata-rata sebesar 51 meter.
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Mount Rinjani is one of the active volcanoes located at West Nusa Tenggara province with caldera morphology that extends extensively in the middle. History records that in the last 800 years there were 12 times volcanic eruptions in the middle of Caldera of Mount Rinjani. There were at least three periods of Rinjani eruption: before the formation of the caldera (pre caldera), the period of caldera formation, and after the formation of the caldera. There is material in the form of pyroclastic rocks in every volcanic eruption. Therefore, the geological processes can be identified by geophysical measurements such as the geoelectric resistivity method. The formation of subsurface rocks can be modeled by inversion using a multichannel system with Dipole-Dipole configuration. The length of the track was 2200 meters, with the space between two electrode array was 10 meters. The 2D modeling result indicated at least three layers of resistivity. The layer of 1,5 Ωm - 5,5 Ωm might be groundwater layer containing clay, the layer of 20,9 Ωm might consist of tuff, and the layer of 54 Ωm - 300 Ωm might contains breccia lava rocks. The last one might be the distribution area of pyroclastic deposits. Therefore, the spread of pyroclastic deposits extends along the line with an average thickness of 51 meters.
| Item Type: | Thesis (Other) |
|---|---|
| Additional Information: | RSFi 552.23 Isw i-1 2019 |
| Uncontrolled Keywords: | Geolistrik, Gunung Rinjani, Kaldera, Piroklastik |
| Subjects: | Q Science > QE Geology > QE471 Sedimentary rocks. Sedimentology Q Science > QE Geology > QE601 Geology, Structural |
| Divisions: | Faculty of Science and Data Analytics (SCIENTICS) > Physics > 45201-(S1) Undergraduate Thesis |
| Depositing User: | Hafsyah Iswari |
| Date Deposited: | 03 Oct 2024 08:09 |
| Last Modified: | 03 Oct 2024 08:09 |
| URI: | http://repository.its.ac.id/id/eprint/65236 |
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