Identifikasi Bahaya Tanah Longsor Menggunakan Metode Very Low Frequency (VLF) Di Bedeng Rejo, Merangin, Jambi

Desa Bedeng Rejo dikenal sebagai salah satu daerah yang berpotensi dalam terjadinya tanah longsor. Metode Very Low Frequency (VLF) digunakan untuk identifikasi bahaya tanah longsor berdasarkan parameter konduktivitas batuan yang didukung kemiringan lereng (slope). Penelitian ini dilakukan menggunakan T-VLF dengan panjang lintasan 200 meter, jarak antar titik ukur 10 meter dan frekuensi pengukuran sebesar 22200 Hz (Jepang). Jenis pengukuran VLF yang digunakan yaitu mode tilt-angle. Ditemukan anomali konduktif yang berada pada rentang 100 - 120 meter dan di bawah permukaan bumi pada 10 - 40 meter dan 170 - 190 meter dengan kedalaman 10 - 30 meter. Perhitungan kemiringan lereng pada lintasan VLF, didapatkan pada jarak 100 – 120 meter yaitu 25% dan pada jarak 170 – 190 meter yaitu 12,5 - 16,67% merupakan lahan dengan kemiringan lereng curam, yang rentan terhadap bahaya tanah longsor, dan mudah tererosi

IDENTIFIKASI LAPISAN BATUBARA MENGGUNAKAN METODE GEOLISTRIK KONFIGURASI SCHLUMBERGER DI LAPANGAN X KECAMATAN BULIAN KABUPATEN BATANGHARI

Studi ini menggunakan salahsatu metode geofisika, geolistrik, yang memberikan informasi bawah permukaan secara spasial berdasarkan sebaran nilai resistivitas. Pengukuran vertical electrical sounding (konfigurasi schlumberger) dilakukan pada 5 titik di Desa Sungai Buluh Kecamatan Bulian Kabupaten Batanghari untuk mendapatkan nilai resistivitas. Model bawah permukaan didapatkan melalui inversi data resistivitas 1-D yang kemudian dikorelasikan dengan data coring yang tersedia di dekat titik pengukuran terkait litologi. Berdasarkan model yang didapat, sebaran nilai resistivitas berada pada rentang nilai 42,5 ohm.m – 1421 ohm.m dengan kedalaman target rata-rata 30,94 m. Resistivitas tinggi (154 ohm.m – 297 ohm.m) diidentifikasi sebagai batubara sub bituminous. Berdasarkan identifikasi lapisan, ditemukan 2 seam batubara dimana seam 1 teridentifikasi pada seluruh titik pengukuran dengan rata-rata ketebalan 1,74 m dan dan kedalaman 13,50 m sedangkan seam 2 hanya terdapat 4 titik pengukuran dengan rata-rata ketebalan 3,325 m dan kedalaman 25,10 m. Disimpulkan bahwa metode geolistrik cocok digunakan dalam identifikasi lapisan batubara dengan resolusi dan akurasi yang baik

APLIKASI GEOLISTRIK KONFIGURASI WENNER DALAM MENDETEKSI PENCEMARAN AIR TANAH AKIBAT GAMBUT PADA DESA SUNGAI TERAP

Sungai Terap Village, Betara District, Tanjung Jabung Timur Regency is one of the areas in Jambi Province which is composed of peat soil. Peat land in this village is used by the community as agricultural and plantation land. As a result, the peat soil is degraded and damaged, causing groundwater pollution. The application of the resistivity geoelectric method can answer the question of groundwater pollution. In the current method that is injected into the earth and measures the potential difference on the surface. Geoelectric measurements were carried out in 4 lines with a length of 200 meters, electrode separation of 10 meters and n = 4. From the measurement results, it was found that groundwater was polluted due to peat soil because it had a very small resistivity value, namely 0.625-2.064  Ωm. This is because the chemical content contained in the peat soil will be carried away by rainwater that enters the surface. The effect of sea water intrusion can also pollute groundwater through drainage channels built on the peatlands. &nbsp

Identification of Peat Land Pollution in Sungai Terap Village Using Wenner Configuration Geoelectric Method

Dewi IK, MZ Nasri, Resta IL, Juventa J.2020. Identification of Peat Land Pollution in Sungai Terap Village Using Wenner Configuration Geoelectric Method. In: Herlinda S et al. (Eds.), Prosiding Seminar Nasional Lahan Suboptimal ke-8 Tahun 2020, Palembang  20 Oktober 2020. pp. xxx.  Palembang: Penerbit & Percetakan Universitas Sriwijaya (UNSRI). Groundwater pollution arising from the conversion of functions on peatlands in Sungai Terap Village. To identify the ground air pollution, the geoelectric method of research using Wenner was carried out. This research was conducted in 4 tracks with a length of 200 meters and the distance between the electrodes was 10 meters with 4 times the electrode spacing. The results of this study are 2D subsurface models in the form of apparent resistivity from the inversion results. The resistivity value generated in the 2D model ranges from 0.381-19 Ωm. The water content at the research location with a very small resistance value between 0.4-1.25 Ωm. The presence of groundwater is estimated to be trapped in the alluvium layer at a depth of 7.75-19.4 meters. The groundwater is thought to have been polluted because it has a resistivity value <10 Ωm. Almost every measurement path is found in polluted air due to rainfall and sea water intrusion

ANALISIS KERENTANAN TANAH FAKULTAS SAINS DAN TEKNOLOGI UNIVERSITAS JAMBI DENGAN MENGGUNAKAN DATA MIKROTREMOR

Research has been carried out to carry out soil vulnerability analysis at the Faculty of Science and Technology, Jambi University. The construction of buildings at the Faculty of Science and Technology has necessitated an analysis of the vulnerability of the land around the buildings at the Faculty of Science and Technology. Based on the regional geology in this area, the Muara Enim formation (TMPM) is formed in the Tertiary age which is composed of rocks from interbedded tuffaced sandstones with tuffaced mudstones, interbedded quartz sandstones with quartz mudstones, interbedded with coal and iron oxide. The rocks formed in this formation are a type of sedimentary rock. To carry out soil vulnerability analysis, the HVSR method is applied to measure microtremors. Microtremors are a geophysical method that uses very small and continuous ground vibrations. This HVSR method is a passive seismic method using three components, namely 2 horizontal components and 1 vertical component. Microtremor measurements on the ground were carried out at 6 points around the building. The results obtained from microtremor measurements using the HVSR method are the natural frequency (f0), amplification factor (A0) and Seismic Vulnerability Index (Kg). The natural frequency (f0) value ranges from 1.30-1.82 Hz, the amplification factor (A0) value ranges from 1.69 - 3.28 times and the seismic vulnerability index (kg) value ranges from 1.814167 to 5.948834 x 10^-6 s^2/cm. Based on the Kanai classification, a frequency value &lt; 2.5 HZ includes soil type IV and soil type II with Alluvial Rock lithology formed from delta sedimentation, top soil, mud. With a depth of 30 meters or more. This area has a very thick surface sediment, more than 30 meters. Based on the classification according to Setiawan, the amlification factor is classified as low (A0&lt;3) to medium (3&lt;A0&lt;6). A low to moderate amplification factor indicates that the rock that makes it up is compact/hard. Based on the Refrizon Classification, the Seismic Vulnerability Index value is in the low (kg&lt;3) to medium (3&lt;kg&lt;6) category. The seismic vulnerability index is low to medium, meaning that if a shock occurs there will be no damage because the vulnerability value is medium - low. Based on these three parameters, it can be concluded that the land around the FST building is still classified as safe from shocks