Analisis GIS Terhadap Gerakan Tanah di Girimulyo, Kulonprogo, D.I. Yogyakarta, dan Kajian Faktor – Faktor Pengontrolnya
Yogi Saktyan Respati1, Asnanto Multa Putranto1, Azim Suwardi1, Irien Akinina Fatkhiandari1, dan Salahuddin Husein2
1) Student at Geological Engineering Department Gadjah Mada University, corresponding email: yogi_onmail@yahoo.co.id, asnantomp@gmail.com, azim_suwardi@yahoo.co.id, qnz_qnina@yahoo.com
2) Lecturer at Geological Engineering Department, Gadjah Mada University
Abstract
There were several landslides had occurred at Girimulyo District, Kulonprogo Regency, Yogyakarta Special Province. These suggest that this area exhibits high potential of mass movement. This research is intended to map and analyze the mass movement potentail by using two methods, i.e. qualitative and quantitative, respectively. Direct observation is on site study for internal factors (e.g. lithologies and geologic structure) and external factors (e.g slope, vegetation, and landuses). Quantitative method utilizes Geographic Information System (GIS) spatial analysis on weighted parameters, i.e. slope, lithologies, geologic structures, and landuses. The research area is mainly composed of weathered lithologies of andesit breccia and breccia tuff covering steep slopes, whilst the rainfall rate reaches up to 2205 mm/y. Both factors are presumed to be the main trigger of mass movement. Result of this research is landslide susceptibility zonation which consist ot four levels which can be used as a basic information for hazard mitigation and regional planning. There were two types of mass movement exist at this area, fall movement were predominant in andesitic intrusion, whereas flow movement mainly took place in andesitic breccias, coralline limestones, and tuffaceous siltstones. This study suggests that more attention and awareness should be paid for areas with high and very high susceptibility levels such as Tanggulangin, Talunombo, and Giripurwo, particularly during high rainy sesason
(this is abstract of my second research and paper which is submitted at 2010 International Geosciences Conference and Exsposition)