scholarly journals Determination of Slip Surface Using 2D Geoelectric Resistivity Method and Laboratory Analysis for Landslide Prone Area Pesawaran, Lampung

Author(s):  
Ikah N P Permanasari ◽  
Vico L Ipmawan ◽  
Endi Khairuman
2020 ◽  
Vol 6 (1) ◽  
pp. 66-76
Author(s):  
Rahmi Mulyasari ◽  
IG Boy Darmawan ◽  
Dersan Surya Effendi ◽  
Sugeng Purwo Saputro ◽  
Hesti Hesti ◽  
...  

Pidada Urban Village, Panjang District, Bandar Lampung is an area that has medium to high landslide potential. One of landslides prone area triggered by rain located on Jalan Raya Suban. The slip surface areas under water-saturated soil is one of causes of landslides triggered by rain. Geophysical method used to detect slip surface is 2D Resistivity Method of Wenner-Schlumberger Configuration. In this study, an analysis of the slip surface has been carried out with the 2D resistivity method of the Wenner-Schlumberger Configuration and determination characteristic of landslide on Jalan Raya Suban. Based on the results of study indicated that the subsurface lithology consists of layers of tuff sediment, sandy clay and breccia. The slip surface is estimated at the boundary the layers of tuff sediment layer and sandy clay with depth (5-15) meters from the ground surface. The results of analysis and observation showed that type of landslide is translational fine-grained soil. Types of slope reinforcement that can be applied are civil and vegetative techniques.


Jurnal MIPA ◽  
2018 ◽  
Vol 7 (2) ◽  
pp. 33
Author(s):  
As'ari _ ◽  
Seni H.J Tongkukut ◽  
Gerald H. Tamuntuan

Kondisi geografis Kabupaten Minahasa merupakan pegunungan dan perbukitan, jalan utama sebagai sarana akses transportasi yang menghubungan daerah bagian selatan dengan ibukota Provinsi Manado berada di lereng-lereng pegunungan ini. Telah terjadi longsor di beberapa tempat dan menutupi jalan utama. Salah satu faktor penyebab longsoran yang sangat berpengaruh adalah bidang gelincir atau bidang geser.  Guna mengantisipasi terjadinya bencana tanah longsor maka sangat penting untuk dilakukan eksplorasi geolistrik untuk inventarisasi data dan informasi potensi terjadinya bencana tanah longsor. Telah dilakukan eksplorasi untuk mengetahui potensi tanah longsor dengan menginvestigasi keberadaan bidang gelincir di Jalan Manado Tomohon. Eksplorasi menggunakan metode geolistrik resistivitas konfigurasi dipol-dipol. Pengukuran dilakukan menggunakan resistivitymeter MAE X612 EM pada 4 lintasan, lintasan 1-4 menggunakan 24 elektroda dan spasi 10 m dengan panjang lintasan 240 m. Data pengukuran diolah menggunakan software RES2DINV, hasil pengolahan berupa tampang lintang resistivitas 2 dimensi. Bidang gelincir diidentifikasi dengan resistivitas (30 - 215) Ωm, yang merupakan lapisan lempung pasiran. Bidang gelincir ditemukan pada semua lintasan, pada lintasan 1, 3 dan 4 terdapat 2 lapisan dengan kedalaman sampai 23 m. Lintasan 2 bidang gelincir teridentifikasi tersebar pada 3 lokasi dengan kedalaman mencapai 20 m.The geographical conditions of Minahasa Regency are mountains and hills, the main road as a means of transportation access that connects the southern region with the capital of Manado Province on these mountain slopes. Landslides have occurred in several places and covered the main road. One of the most influential factors for landslides is the slip surface or shear surface. To anticipate landslides, it is very important to explore geoelectricity for an inventory of data and information on potential landslides. Exploration has been carried out to determine the potential of landslides by investigating the existence of slip surface on Jalan Manado Tomohon. Exploration using geoelectric resistivity method dipole-dipole configuration. Measurements were made using MAE X612 EM resistivitymeter on 4 lines, line 1-4 using 24 electrodes and 10 m spacing with 240 m line length. Measurement data is processed using RES2DINV software, the results of processing are 2-dimensional resistivity crossection. The slip surface is identified by resistivity (30 - 215) Ωm, which is a layer of sandy clay. The slip surface is found on all lines, on lines 1, 3 and 4 there are 2 layers with a depth of up to 23 m. Slip surface at line 2 are identified spreading over 3 locations with depths reaching 20 m.


Jurnal MIPA ◽  
2018 ◽  
Vol 7 (2) ◽  
pp. 1
Author(s):  
Mercyas Tunena ◽  
As’ari ◽  
Gerald H. Tamuntuan

Penelitian ini bertujuan untuk memetakan struktur bawah permukaan di Jalan Raya Manado - Tomohon, di Desa Tinoor  untuk mencari keberadaan bidang gelincir sebagai mitigasi bencana alam tanah longsor. Pengukuran dalam penelitian ini dilakukan dengan menggunakan resistivitymeter MAE 612-EM, dengan jumlah elektroda yang dipakai 32 buah, spasi 2 meter, panjang lintasan 64 meter, jumlah ,lintasan 4, dan menggunakan metode geolistik resistivity konfigurasi Wenner Alfa. Data dengan format DAT diolah menggunakan software notepad dan res2dinv. Hasil pengolahan adalah tampang lintang resistivity 2D bawah permukaan yang menggambarkan keberadaan bidang gelincir.Hasil penelitian diperoleh lapisan lempung pasiran yang merupakan bagian dari bidang gelincir dengan resistivitas (30 - 215) Ω.m. Lokasi lapisan lempung pasiran pada lintasan 1 didapatkan 3 lokasi, lintasan 2 didapatkan 4 lokasi, lapisan 3 didapatkan 1 lokasi, dan lintasan 4 didapatkan 2 lokasi. Lokasi lempung pasiran terdapat pada kedalaman  (1 - 6) meter dengan panjang (12 - 14) meterThis research aims to map the subsurface structure on the Manado - Tomohon main road, in Tinoor Village to find the existence of the slip surface as the mitigation of landslide disaster. The measurements in this research were carried out by using the MAE 612-EM resistivitymeters, with 32 electrodes, 2 meters spacing, 64 of meter line length, number of line 4, and using  Wenner Alfa configuration geoelectric resistivity method. Data with DAT format is processed using notepad and res2dinv software's. The result of this prosessing is a cross-sectional resistivity 2D, that describe the existence of the slip surface.The result was obtained that the sandclay layer which is part of the slip surface with resistivity 30 - 215 ohm meter. The location of sandclay layers on line 1 was found 3 locations, line 2 was found 4 locations, line 3 was found 1 location, and line 4 was found 2 locations. The location of the sandclay is at depth (1-6) meters with length (12-14) meters.


Landslides ◽  
2021 ◽  
Author(s):  
Chuang Song ◽  
Chen Yu ◽  
Zhenhong Li ◽  
Veronica Pazzi ◽  
Matteo Del Soldato ◽  
...  

AbstractInterferometric Synthetic Aperture Radar (InSAR) enables detailed investigation of surface landslide movements, but it cannot provide information about subsurface structures. In this work, InSAR measurements were integrated with seismic noise in situ measurements to analyse both the surface and subsurface characteristics of a complex slow-moving landslide exhibiting multiple failure surfaces. The landslide body involves a town of around 6000 inhabitants, Villa de la Independencia (Bolivia), where extensive damages to buildings have been observed. To investigate the spatial-temporal characteristics of the landslide motion, Sentinel-1 displacement time series from October 2014 to December 2019 were produced. A new geometric inversion method is proposed to determine the best-fit sliding direction and inclination of the landslide. Our results indicate that the landslide is featured by a compound movement where three different blocks slide. This is further evidenced by seismic noise measurements which identified that the different dynamic characteristics of the three sub-blocks were possibly due to the different properties of shallow and deep slip surfaces. Determination of the slip surface depths allows for estimating the overall landslide volume (9.18 · 107 m3). Furthermore, Sentinel-1 time series show that the landslide movements manifest substantial accelerations in early 2018 and 2019, coinciding with increased precipitations in the late rainy season which are identified as the most likely triggers of the observed accelerations. This study showcases  the potential of integrating InSAR and seismic noise techniques to understand the landslide mechanism from ground to subsurface.


2021 ◽  
Author(s):  
Dávid Bednár ◽  
Jakub Dolniak ◽  
Martin Lištjak ◽  
Vladimír Nečas

2021 ◽  
Vol 9 (11) ◽  
pp. 422-430
Author(s):  
Achoh Mardochee Ephraim ◽  
◽  
Agadjihouede Hyppolite ◽  
Gangbe Luc ◽  
Aizonou Romaric ◽  
...  

The present study aim to estimate the ratio of aquaculture in the phosphorus and nitrogen concentrations determined in the Toho - Todougba lagoons. For this purpose, the two lagoons were subdivided into 7 stations for the determination of phosphorus and nitrogen concentrations in the water column. Production data from 2017 to 2019 were collected from the Direction of the Ficheries Production and from the literature. Data for 2020 were collected directly from fish farmers. Annual tilapia production was estimated by year and the amounts of phosphorus and nitrogen released from aquaculture are deduced based on the ratio of Montanhini Neto & Ostrensky (2013). The concentration of each of these nutrients was estimated by station and compared to the concentration determined by laboratory analysis of the water. This methodology shows that the amount of phosphorus and nitrogen released to the environment varies from 0.49 mg/L to 0.18 mg/L for phosphorus and from 1.53 mg/L to 0.58 mg/L for nitrogen. The lowest values are obtained in 2020 and differ significantly from the other years (p <0.05). The quantity of phosphorus discharged is higher at the high production stations (Tonon 0.20 mg/L and Lokohoue 0.11 mg/L). Some of this is stored in the sediment. The nitrogen generated by aquaculture is significantly lower than the average determined in water (p <0.05). However, the concentration determined is still related to the amount of organic matter released due to aquaculture. Although aquaculture is not the only source of nutrient release to water, strategies for aquaculture with less nutrient release should be determined.


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