Joenil Kahar, Joenil
Geodesy Research Division, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung, Ganesha 10, Bandung 40132, West Java, INDONESIA

Published : 2 Documents

Found 2 Documents

Ketelitian Model Kinematik untuk Memprediksi Karakteristik Longsor (Studi Kasus : Zona Longsor di Ciloto-Puncak, Jawa Barat) Sadarviana, Vera; Z. Abidin, Hasanuddin; Kahar, Joenil; Santoso, Djoko; K, Wedyanto
Indonesian Journal of Geospatial Vol 1, No 1 (2012)
Publisher : Indonesian Journal of Geospatial

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Abstract. The geodetic approach based on extraterrestrial survey measurements can be used to study phenomenon, especially to monitoring of material movement characteristic. Landslide is one of prominent catastrophe that continuously affecting in Indonesia, especially in rainy season. In mountainous terrain and areas of steep slope of Indonesia, landslides are frequent, especially where land cover has been removed. Landslides destroy not only environment and property, but usually also cause deaths. Landslide mitigation is therefore very crucial and should be done properly. The velocity and acceleration of several monitored point covering the landslide zone area can be estimated using the geodetic approach. Knowing the relation among these three variables in spatial and temporal domain will be useful for identifying the characteristics of landslide. This information can then be used for better strategy of landslide hazard mitigation. Accuracy of the use of kinematic models for prediction of avalanche characteristics need to be validated so that mitigation will be done correctly. Validation is done by doing a comparison between model predictions and the size of the data and statistical tests for the feasibility of prediction of each point of the GPS monitor. Validation is known that the predicted results at some GPS monitor point is not suitable for use. With the vector of the movement of materials, we know the direction and scalar, velocity and acceleration of material displacement. The movement of landslide materials at Ciloto Zone dominated north-west to south-easterly direction and speed to slow very slow (creep). Keywords: accuracy, characteristics, kinematic model, landslide.
Jurnal Geologi dan Sumberdaya Mineral Vol 20, No 2 (2010): Jurnal Sumber Daya Geologi
Publisher : Pusat Survei Geologi

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Slip surface is delaminates between sliding material and undisturbed slope material. In limit equilibrium method, slip surface is used as reference for safety factor calculation. Landslides phenomenon can be observed using of GPS satellite technology to mitigation and material displacement monitoring. For that purpose, this research is carried out to estimate characteristic, type and slip surface position at Ciloto landslide zone by GPS survey.First, estimation of slip surface is carried out by slope surface profile which referred to same direction of horizontal displacement of monitored points. The same direction of horizontal displacement at several monitored points indicate that the monitored points can be located at the same slip surface. Second, maximum-minimum function of geometric method and polynomial approach, including graphical method by velocity trend line plotting for each monitored point, were done to find out point position at slip surface. Ideal planar slip surface is determined by infinite slope analysis and circular slip surface is determined by circle arc analysis. Estimation of slip surface by geodetic method approach couldn't give result because geodetic data describe slope surface. By intersection of velocity trend line of monitored point, it can gave estimation of slip surface location. Geodetic approach could gave estimation of scarp position as well as crack which is indicate beginning of slip surface. Locations of scarp in vertical profile have suitability with result of geology research at same study area.Ciloto landslide zone is classified in very slow velocity landslide (5 x 10-5 - 5 x 10-7 mm/second). The characteristic of horizontal displacement has various direction for each monitored point. Vertical displacements of monitored point have subsidence and uplift or bulging. That characteristic formed hummocky terrain and the other side of zone have gradual slope. From the research, the landslide type at Ciloto zone is multiple compound (rotational and translational) debris slides.Keywords : geodetic method, GPS survey, landslide characteristic, landslide type, slip surface, multiple landslide, scarp