Sebaran Aspek Keruangan Tipe Longsoran Di Daerah Aliran Sungai Alo Provinsi Gorontalo (Spread of Spatial Aspect of Landslide Types at Alo Watershed in Gorontalo Province)

Abstract

Distribution of spatial aspect of landslide at ALO Watershed of Gorontalo Province has been studied by providing it through form of spread landslide maps at scale of 1 : 50.000. Research site involved all areas of ALO Watershed in Gorontalo Province as having an area of 7,588 Ha. Research sampling was conducted through accidental sampling as exploring all areas across the region prone to landslides at ALO Watershed in order to invent potential spot of landslide occurence. Regarding to the discussion and spread landslide, it was conducted an observation and measurement toward landslide which was occured to all areas of ALO Watershed 15 number spots of landslide occurance. Type of landslide was determined by the measurement and observation of landslide morphometry toward classification index and analysis result. Then it was distributed into the map of spread landslide at scale of 1 : 50.000 in order to acknowledge the spatial spread of landslide occurence at ALO Watershed in Gorontalo Province. Based on the morphometry analysis and classification index of landslide, they showed that landslide types are rotational slide, planar slide, slide flow, and rock block slide. Landslide occurence of ALO Watershed in Gorontalo Province has been spread in areas with steep slope and very steep slopes by having convex surface shape and tend to be straight. It also occures to the area of clay texture and silted loam, and types of volcanic and igneous rocks which contained high silica and encountering weathering. Regarding to the administration area, landslide occurence is spread to the subdistrict of Tibawa, Pulubala, and Isimu Utara subdistricts